Authors:Yanyan Wei; Xiaoyue Ma Abstract: Polymer materials containing Diels–Alder (abbreviated DA) groups show good self-healing ability under certain conditions. In this study, the thermal reversible DA bond was introduced into polyurethane by the design of molecular chain to obtain the self-healing properties. The pre-polyurethane (HTK) end-capped with furan rings was synthesized by hexamethylene diisocyanate trimer and furfuryl alcohol firstly. Then, HTK was mixed with bismaleimide (BMI) to synthesize the cross-linked polyurethane HTK-PU. Finally, the properties of the HTK-PU were characterized. It can be observed from DSC that the DA reaction occurred at 76°C and the r-DA reaction occurred at 109.5°C. This cross-linked polyurethane shows a remarkable high hardness (shore D80). When preserved at 80°C for 6 hr, the self-healing efficiency of the HTK-PU was 53.75% known from tensile test, and cracks on it virtually disappeared as observed from polarizing microscope (POM). When preserved at 80°C for 12 hr, the self-healing efficiency was 67.56%. PubDate: 2017-06-19T00:11:00.867634-05: DOI: 10.1002/adv.21857
Authors:Muthu Rajamani Jayasree; Srinivasan Anandakumar, Muthukaruppan Alagar Abstract: The present work aims at the toughening of DGEBA epoxy-cyanate ester hybrid with caprolactam and its subsequent reinforcement with different weight percentages of (1, 3, 5, and 7 wt%) 3-glycidylpropoxytrimethoxysilane functionalized Al-MCM-41 (F-Al-MCM-41) to fabricate F-Al-MCM-41 reinforced caprolactam toughened DGEBA epoxy-cyanate ester polymer nanocomposites. 1H NMR and 13C NMR data confirmed the formation of epoxy cyanate ester. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) results ascertained the curing behaviour of polymer composites. Data from thermal and dielectric studies reveal that 7 wt% F-Al-MCM-41 reinforced caprolactam toughened DGEBA epoxy-cyanate ester exhibits superior thermal stability and dielectric constant than that of a neat composite. The SEM- EDAX analysis investigated the surface morphology of polymer composites. Data obtained from DMA showed that 7 wt% polymer nanocomposite possesses the highest storage modulus among the samples. PubDate: 2017-06-14T23:43:29.292214-05: DOI: 10.1002/adv.21849
Authors:Hemjyoti Kalita; Rashmirekha Kamila, Smita Mohanty, Sanjay Kumar Nayak Abstract: Biobased polymer has taken tremendous attention in recent times. In the present study bio-based polyurethane have been synthesized from the vegetable oil i.e., dehydrated castor oil, 1,4-butanediol and isophorone diisocyanate in presence of a catalyst by solution polymerization method. Then polyurethane nanocomposites were synthesized using different amount of nanoclay (C30B) (1, 3 and 5 wt%). The synthesis of polyurethane and its nanocomposites were confirmed by FTIR and XRD analysis. The mechanical properties such as tensile strength (2.2–4.5 MPa), elongation at break (299%–435%) hardness (46–70) and abrasion resistance (351–201 mg/1,000 cycles) increased with the increase of nanoclay content. The initial thermal degradation temperature found to increase from (220 to 290°C) with the increase of nanoclay content in the nanocomposites. The nanoclay was interacted with the hard segment of the matrix polymer as reflected from the atomic force microscopy studies. Weathering study revealed that nanocomposites have higher weather resistance capacity than pristine polyurethane. It can be concluded that the prepared nanocomposites might be good outdoor topcoat materials. PubDate: 2017-06-11T23:30:38.946649-05: DOI: 10.1002/adv.21853
Authors:Muhammad Zaman; Muhammad Hanif Abstract: The purpose of the study was to design a dosage form with ability to deliver drug immediately, hence providing rapid relief in certain pain ailments. Meloxicam (MLX) was selected as a model drug and buccal films were designed by using the solvent casting technique. A central composite rotatable design (CCRD) was used as a statistical tool to design and optimize the film formulations. No noticeable interaction was found between the drug and polymer when they were subjected to Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) revealed the smooth surface of the film and uniform mixing of drug and polymer. X-ray diffractometry (XRD) was carried out to observe crystalline and amorphous nature of meloxicam. Differential scanning calorimetric (DSC) analysis was used to investigate the thermal behavior of free drug and drug-loaded formulation. The prepared film showed good mechanical property as folding endurance was found to be greater than 100 in all formulations. The cumulative drug release was found to be more than 80% in initial at dissolution time of 5 min, when the prepared films were subjected to dissolution studies in phosphate buffer at pH 6.8. Thus, it can be concluded that the hydrophilic polymer and plasticizer have definite impact on formulation and characteristics of rapidly dissolving buccal films and have the ability to prepare a suitable immediate release buccal film of meloxicam. PubDate: 2017-06-09T23:20:30.78906-05:0 DOI: 10.1002/adv.21841
Authors:Mozhgan Hayasi; Naghi Saadatjoo Abstract: This work describes the removal of three pharmaceuticals, namely ceftriaxone sodium (CFX), diclofenac sodium (DCF) and atenolol (ATN) from water using magnetic poly (styrene-2-acrylamido-2-methyl propanesulfonic acid) (St-AMPS) adsorbent. This adsorbent was characterized by several techniques such as FTIR, TEM, TGA, VSM and DLS. Three kinetic models, pseudo-first-order, pseudo-second-order and intra-particle diffusion models were used to study the adsorption kinetics. The results showed that the adsorption kinetics of pharmaceuticals onto magnetic poly (St-AMPS) adsorbent followed the pseudo-second-order model and were relatively rapid. In addition, it was found that the intra-particle diffusion was not the sole rate-controlling step and the adsorption of pharmaceuticals onto adsorbent occurred via two steps adsorption process. The experimental data were fitted with three isotherm models including Freundlich, Langmuir and Dubinin-Radushkevich (D-R). It was found that the adsorption of pharmaceuticals onto magnetic poly (St-AMPS) nanoparticles was the best described by the Langmuir model. Maximum adsorption capacities of 150.602, 47.824 and 119.904 mg/g were obtained for DCF, ATN and CFX, respectively. Also the obtained free energy from D-R isotherm (6.19, 4.93 and 6.45 kJ/mol for DCF, ATN and CFX respectively) indicated that the adsorption process was a physiosorption. Magnetic poly (St-AMPS) adsorbent could be recycled for removal of CFX, DCF and ATN by alkaline aqueous solution (pH 8). Therefore, this adsorbent can act as a promising adsorbent for water treatment processes. PubDate: 2017-06-08T23:40:35.414366-05: DOI: 10.1002/adv.21852
Authors:Mohammad Ali Tavanaie; Roya Dastjerdi, Nazanin Sepehrian, Alireza Ghasami Abstract: Nano-titanium oxide/nano-zinc oxide/poly(ethylene terephthalate) (nano-TiO2/nano-ZnO/PET) nanocomposite fibers were successfully prepared by a laboratory-scale melt spinning process. The properties of pure and modified PET fibers including tensile (tenacity and elongation at break) and thermal properties, and the dyeability properties of cationic dyes with and without carrier were studied. The modified PET nanocomposite fiber containing 0.15 wt% nano-titanium dioxide and 0.15 wt% nano-zinc oxide showed the best cationic dye adsorption property, excellent washing fastness and good light fastness. Also, a significant effect on the dye adsorption of modified PET fibers was observed at boiling temperature due to the presence of carrier agent. PubDate: 2017-06-08T02:05:36.709023-05: DOI: 10.1002/adv.21848
Authors:Matthew J. Smith; Casparus J. R. Verbeek Abstract: Novatein thermoplastic protein was blended with modified polyethylene (containing either epoxy, carboxylic acid functionalities partially neutralised to produce zinc carboxylate salts, or maleic anhydride functionalities) to alter blend morphology and to manipulate thermal and mechanical properties. Up to 40 pphNovatein polyethylene (PE) was blended with Novatein by extrusion and injection moulding. Using zinc ionomer resulted in optimal properties and was compatible with a finely dispersed morphology at high content; high interfacial tension (σ) and a viscosity ratio (λ) of ~1 was observed. Unmodified blends and those containing epoxy functionalities showed co-continuity at low PE content. Whilst co-continuity appeared to increase impact resistance, other mechanical properties decreased due to lack of phase interaction. Maleic anhydride-grafted-polyethylene blends showed a finely dispersed PE phase, yet was less compatible. Zinc ionomer was deemed to be the most appropriate for modification of mechanical properties in Novatein. PubDate: 2017-06-07T23:25:59.509903-05: DOI: 10.1002/adv.21847
Authors:Fumitoshi Noguchi; Yuanbing Zhou, Kenichiro Kosugi, Yoshimasa Yamamoto, Phan Trung Nghia, Masao Fukuda, Seiichi Kawahara Abstract: Strain-induced crystallization of natural rubber (NR) can greatly influence the mechanical properties of NR blends. In this study, we investigated the effect of strain-induced crystallization on the tear energy (G) of NR/styrene butadiene rubber (SBR) blends with different compositions and cross-link densities. Using a shift factor, we could superimpose G of an SBR blend and an NR/SBR (1/9) blend onto a single master curve. In contrast, G of NR was split into two master curves. Although the master curve of G for the NR/SBR (3:7) blend was split, increasing the cross-link density threefold made it possible to superimpose it onto a single master curve. Strain-induced crystallization of NR in the NR/SBR blend did not occur as a result of decreasing the NR content, increasing the cross-link density, or removing fatty acids. Together, these findings indicate that strain-induced crystallization of NR plays an important role in the mechanical properties of the blend. PubDate: 2017-06-06T05:50:31.011419-05: DOI: 10.1002/adv.21843
Authors:Siang Tandi Gonggo; Bunbun Bundjali, Ketut Hariyawati, I Made Arcana Abstract: The membranes of sulfonated polystyrene, lignosulfonate and nano-silica (SPS-LS-SiO2) that contain different percentages of nano-silica (1%–5% [w/w]) were prepared and characterized for polymer electrolyte membrane fuel cell (PEMFC). Nano-silica is an inorganic compound with a surface area of 200 m2/g, and it has a hygroscopic property so that the presence of nano-silica in membrane can increase properties of membrane. The SPS-LS-SO2 membranes were prepared by casting polymer solution and membranes were characterized by functional groups analysis, water uptake, ion exchange capacity (IEC), proton conductivity, methanol permeability, thermal stability, mechanical properties, and surface morphology. The results show the increase of nano-silica composition in SPS-LS-SiO2 membranes, the IEC, water uptake, proton conductivity increase, but a pore size of membrane decreases. On the other hand, it can maintain the mechanical strength of membranes. The SPS-LS-SiO2 membranes with nano-silica composition of 2%–5% (w/w) have the same properties with Nafion®117, especially in proton conductivity at the same treatment and measurement conditions, and its methanol permeability is about 28%–35% smaller than that of Nafion®117 (2.09 × 10−6 cm2/s), so this SPS-LS-SiO2 membrane could be used as a polymer electrolyte membrane for direct methanol fuel cell (DMFC) application. PubDate: 2017-06-05T04:50:20.04672-05:0 DOI: 10.1002/adv.21844
Authors:Gianluca Cicala; Salvatore Mannino, Alberta Latteri, Giulia Ognibene, Giuseppe Saccullo Abstract: Two different epoxy monomers, based on the diglycidylether of bisphenol A (DGEBA) and triglycidyl-p-aminophenol (TGAP), which are di- and tri-functional, respectively, were mixed in varying proportions and cured with bis(2,6-diethylaniline) (MDEA). Toughened epoxy resins were prepared by adding a coPolyethersulfone (coPES) to the resin mixture. The dynamic mechanical and morphological properties of the cured materials were measured. It was found that the blends based on TGAP presented different viscoelastic and morphological behavior compared to DGEBA-based formulations. Mixing TGAP with DGEBA resulted in increased glass transition temperature and homogeneous phase morphology distribution. PubDate: 2017-06-02T04:26:01.533355-05: DOI: 10.1002/adv.21845
Authors:Zhixiang Cui; Zifeng Zheng, Luyin Lin, Junhui Si, Qianting Wang, Xiangfang Peng, Wenzhe Chen Abstract: The drug-loaded polyvinyl alcohol (PVA)/chitosan (CS) composite nanofibers intended to be used as matrix for transdermal drug delivery were fabricated by electrospinning, and then crosslinked through glulataraldehyde (GA). The morphology, chemical structure, thermal behavior, mechanical properties, hydrophilicity and drug release properties of drug-loaded PVA/CS composite nanofibers before and after crosslinking were characterized. The results showed that the morphology of PVA/CS composite nanofibers was not been destroyed in both crosslinking and in vitro drug release process. The Young's modulus, tensile strength, thermal properties and hydrophobicity of crosslinked PVA/CS composite nanofibers significantly increased in comparison with those of PVA/CS (without crosslinking) due to the formation of crosslinking network structure. In vitro release studies showed that crosslinked PVA/CS composite nanofibers had lower drug release rate and smaller amount of drug burst release than that of PVA/CS. According to release exponent “n”, the release of ampicillin sodium from crosslinked PVA/CS composite nanofibers fit to the Fickian diffusion mechanism. Those results demonstrate the potential utilization of crosslinked PVA/CS composite nanofibers as a transdermal drug delivery system. PubDate: 2017-06-02T01:05:49.115859-05: DOI: 10.1002/adv.21850
Authors:Dan Zhang; Eusebio Cabrera, Yanan Zhao, Ziwei Zhao, Jose M. Castro, Ly J. Lee Abstract: Multifunctional carbon nanofiber (CNF) nanopaper-enhanced glass fiber reinforced epoxy polymer composites (GFRPC) with improved sand erosion resistance, mechanical properties, and electromagnetic interference (EMI) shielding have been fabricated and tested in this work. Preformed CNF thin film or nanopaper, made of dense and entangled nanofiber networks, was molded on the surface of GFRPC as a surface protection layer by vacuum-assisted resin transfer molding. A fivefold improvement in sand erosion resistance in terms of sand erosion rate, and up to 24% improvement in flexural strength were achieved after the incorporation of CNF nanopaper onto thin GFRPC. The CNF nanopaper-enhanced GFRPC showed an EMI shielding of 33–40 dB within a frequency range of 30 MHz to 1.5 GHz. This multifunctional composite material shows good potential for use in wind power industry, commercial electronics housings, and the automotive industry. PubDate: 2017-06-02T00:25:38.50368-05:0 DOI: 10.1002/adv.21846
Authors:Kashif Barkat; Mahmood Ahmad, Muhammad Usman Minhas, Ikrima Khalid, Bushra Nasir Abstract: An oral route of administration is a most acceptable route for a patient, so we designed chemically cross-linked polyethylene glycol-co-poly(methacrylic acid) oral hydrogels (PEGMA 4000) by free radical polymerization method for pH-responsive colon target delivery of oxaliplatin (OXP). Polyethylene glycol (PEG 4000) was cross-linked chemically with methacrylic acid (MAA) in distilled water. Ammonium peroxodisulfate (APS) and N, N-methylene bisacrylamide (MBA) were used as initiator and cross-linker respectively. OXP was loaded in prepared hydrogels. FTIR, DSC, TGA, SEM, and XRD were conducted for characterization of developed hydrogels which endorsed the formation of new polymeric network. The pH-sensitive behavior of hydrogels was observed by swelling dynamics and equilibrium swelling ratio at low (1.2) and higher pH (7.4). Toxicity study was also conducted on rabbits to evaluate toxicity and biocompatibility of developed carrier system to biological system. Hydrogels with higher PEG 4000 concentration showed maximum swelling and higher drug loading at 7.4 pH. Toxicity study confirmed the developed hydrogels as non-toxic and biocompatible for biological system. Resultantly, these hydrogels can become an excellent candidates for colon targeting of OXP to treat colorectal cancer with no toxicity. PubDate: 2017-05-25T01:55:32.710437-05: DOI: 10.1002/adv.21840
Authors:Ren Hao Liu; Wen-Bin Young, Hsu Pe Ming Abstract: This article discusses the application of an in-mold decoration (IMD) technology for the development of three-dimensional molded interconnect devices (3D-MID). The 3D-MID process uses the film printing technology to print the circuit pattern on a plastic film, and then deform it to the shape of the component by thermoforming. Then, the plastic film is placed inside the mold cavity for injection molding, and is attached to the surface of the component after molding. Experiments were performed for the 3D-MID process using a semisphere shape. A simple geometric model was also proposed to correlate the printed film patterns before and after the thermoforming. The geometric model will be used to design the required printing pattern on a 2D film for a given 3D pattern on a component. PubDate: 2017-05-22T06:25:37.76316-05:0 DOI: 10.1002/adv.21830
Authors:Xueyan Liu; Qiurui Liu, Feifan Kong, Xuguang Qiao, Zhixiang Xu Abstract: In this study, a molecularly imprinted polymer (MIP)-fluorescent probe based on hydrophobic CdSe/ZnS quantum dots (CdSe/ZnS@MIP) was designed and synthesized by bulk polymerization for detecting methamidophos (MAP). The CdSe/ZnS@MIP was characterized by Fourier-transform infrared spectroscopy, thermo-gravimetric analysis and adsorption properties, and it exhibited good adsorption capacity and fluorescent stability, and excellent selectivity. Under optimal conditions, the fluorescence showed a good linear decrease in the range of 3.50 × 10−7–0.71 × 10−3 mol/L with a correlation coefficient of 0.995. The limit of detection of the fluorescent probe was 9.16 × 10−8 mol/L, and the relative standard deviation of the method for nine replicate analyses of 4.0 × 10−6 mol/L MAP was 4.1%. Apple and pear samples spiked with MAP at three levels were extracted and determined by the presented method with good recoveries (89.7%–94.9%). The accuracy of the method was verified by gas chromatography for the detection of kidney beans, leek and cucumber samples, and no significant difference was observed for the results of two methods. PubDate: 2017-05-22T02:00:32.702102-05: DOI: 10.1002/adv.21838
Authors:Mehdi Hatami; Nader Djafarzadeh, Hamed Hasanabadi Abstract: In this research, the effects of organic-inorganic hybrid nanocomposites as novel nanostructure additives in paint compositions were studied. The silica modified TiO2 nano structure was prepared by using sol–gel method. The TEM analysis indicated that these particles were in the range 10–15 nm. The organo silicone containing polymer was prepared by free radical polymerization process. The prepared polymer/mixed metal oxides nanocomposites were fabricated and demonstrated as nanostructure additives. The prepared nanocomposite was introduced into the road marking material formulation. In the first part of the current study, the prepared samples were evaluated by quality control experiment such as compatibility and color visualization tests. Also specific experiments such as hydrophobicity, adhesion, exposure to weathering conditions, self-cleaning nature of the samples, gloss appearance, hardness of the prepared samples, anti-pollution investigation, moisture resistance, and heat-cold cycle's tests were evaluated. The environmental issue of the road marking material and also the dirtiness removal efficiency by using nanostructure coating was investigated. The prepared samples showed 4–7 mg weight loss per hundred square centimeters during the exposure to 300 h by 313 nm UVB irradiation. The best photocatalytic performance in road marking application was found for NA 3% sample. PubDate: 2017-05-20T01:40:32.049367-05: DOI: 10.1002/adv.21842
Authors:Shiv Kumar; Katharina Achazi, Kai Licha, Priyanka Manchanda, Rainer Haag, Sunil Kumar Sharma Abstract: Cyanine 3 is an amphiphilic fluorescent dye used in optical imaging, bioengineering, and for cellular internalization. However, the applications of the dye are limited due to its poor aqueous stability, aggregation tendency, and lack of selectivity. To address these issues, we have developed PEG and azidotriglycerol based dendronized polymers using Novozym 435 as a biocatalyst under solvent free conditions. The resulting polymer having azido and hydroxyl functionalities available in the backbone were further grafted with alkyl chains and polyglycerol dendrons using esterification and ‘Click’ chemistry approach. These polymers form stable micelles at micromolar concentration. All the polymers were characterized from their spectral data and their tendency to encapsulate cyanine 3 dye studied using UV-Vis and fluorescence spectroscopy. The cytotoxicity study of the polymers performed against A549 cell lines suggests them to be nontoxic up to a concentration of 500 μg/ml. PubDate: 2017-05-15T01:07:07.683415-05: DOI: 10.1002/adv.21839
Authors:Yuan Lei; Changbing Li, Xiaowei Fu, Jingxin Lei, Changlin Zhou Abstract: The polyamide-6 based poly(ether-block-amide) (PEBA) multiblock copolymers were reactively prepared in typical processing equipment, torque rheometer. The reactive processing conditions of PEBA were discussed in details on the base of the tensile strength as the main quantization parameter and the torque rheological curves. The optimized reaction temperature, reaction time, and rotational speed were 150°C, 10 min, and 40 rpm respectively. The chemical structure, tensile properties, thermal transition, thermal stability, water absorption, and solubility in organic solvents of PEBA prepared in optimized reaction conditions were characterized by Fourier transform infrared spectroscopy, tensile testing, differential scanning calorimetry, thermogravimetric analysis, and soaking testing in water and organic solvents. The tensile strength and elongation at break of PEBA are 35.9 MPa and 580% respectively. The glass transition temperature and melting temperature of soft segment of PEBA are −50 and 15°C, respectively; the glass transition temperature and melting temperature of hard segment of PEBA are 50 and 140°C respectively. Meanwhile, the PEBA has low water absorption, robust organic solvent resistance, and good thermal stability. The optimization process of PEBA will give the deep understanding of reactive processing of polymer materials. PubDate: 2017-05-08T01:05:04.035672-05: DOI: 10.1002/adv.21837
Authors:Emre Baştürk; Emrah Çakmakçi, Seyfullah Madakbaş, Memet Vezir Kahraman Abstract: Proton-conductive electrospun nanofibers are promising potential materials for several advanced technological applications such batteries, sensors, and fuel cells. In this work, we prepared poly(vinyl butyral)/polyaniline (PVB/PANI) nanofibers via electrospinning and determined their proton conductivities. Structural characterization of the nanofibers was performed by FTIR analysis. Surface morphology of the nanofibers was determined by SEM and AFM. The addition of PANI significantly affected the fiber morphology, and over 90% reduction (with respect to neat PVB nanofibers) in the average nanofiber diameters was observed. Nanofiber mats were doped with polyphosphoric acid. The proton conductivity of the 2 wt.% PANI containing blend nanofibers was found as 18 × 10−6 S/cm at room temperature and at 100% humidity. PubDate: 2017-05-08T00:33:55.851469-05: DOI: 10.1002/adv.21836
Authors:Prabina Kumar Patnaik; Sandhyarani Biswas Abstract: This article reports on mechanical and slurry abrasion response of a new class of material developed by reinforcement of blast furnace slag (BFS) in needle-punched nonwoven polyester fabric epoxy composites. These epoxy-based composites are prepared by the hand-lay-up technique with the variation of BFS content (0, 5, 10, and 15 wt. %) and at constant fiber loading. It is observed that the mechanical properties of the composites are improved significantly with the incorporation of filler. However, the properties like tensile, flexural and inter-laminar shear strength are reduced beyond 10 wt. % of filler loading. Abrasive wear behavior of these composites is studied in the slurry environment by a slurry abrasion test rig (ASTM G105). The specific wear rate of composites under a steady-state condition with respect to normal load and sliding velocity is found to decrease with the increase in filler loading. Further, experimental design through Taguchi's L16 orthogonal array is applied to determine the optimal parametric combination which reduces the wear rate. The parametric combination among sliding velocity of 0.93 m/s, normal load of 30 N, sliding distance of 600 m, silica sand size of 100 μm and filler loading of 5 wt. %, produces an optimum specific wear rate. The morphological study is conducted on abraded composite surfaces by using scanning electron microscopy (SEM) and possible wear mechanisms responsible for wear have been discussed. PubDate: 2017-05-02T10:49:51.264891-05: DOI: 10.1002/adv.21835
Authors:Hideyuki Uematsu; Yu Suzuki, Yoshiyuki Iemoto, Shuichi Tanoue Abstract: Composites of polypropylene (PP) and PP blended with maleic anhydride-grafted polypropylene (MAPP) reinforced with short glass fibers were prepared via extrusion compounding and injection molding techniques. The fiber length did not significantly change irrespective of the presence of MAPP after compounding and injection molding. However, the tensile strength of PP/fiber showed significant improvement after MAPP addition. The interfacial shear strength between PP and fiber increased with the addition of MAPP. Examination of the failure surface of a dumbbell specimen after tensile testing confirmed that the fiber highly orientated in the flow direction in the PP/MAPP matrix. The tensile strength enhancement was attributed to the improvement of the interfacial shear strength between PP and fiber. Moreover, in the injection molding process, there was high orientation of the fiber in the flow direction when there was MAPP. We concluded that the presence of MAPP causes increased orientation of the fiber. PubDate: 2017-04-27T11:12:28.713727-05: DOI: 10.1002/adv.21834
Authors:Na Liang; Yufei Tu, Jing Xu, Dongzhi Chen, Hongwei Zhang Abstract: A novel strategy for fabricating nanocomposite anion exchange membranes (AEM), which can construct self-assembled ionic channels via in situ Menshutkin reaction, is proposed. The TEM image of a nanocomposite AEM based on chloromethylated polysulfone (CMPSF) and functionalized polyhedral oligomeric silsesquioxane (POSS) confirms the existence of core-shell clusters. The ionic conductivity of these nanocomposite AEMs shows a notable increase when the content of functionalized POSS exceeds the percolation threshold. Furthermore, the optimized nanocomposite AEM has higher ionic conductivity than the control AEM with similar ion-exchange capacity due to the well-developed morphology. PubDate: 2017-04-24T04:45:30.818681-05: DOI: 10.1002/adv.21831
Authors:Andrea Dorigato; Marco Brugnara, Alessandro Pegoretti Abstract: In this study, novel electrically conductive polymeric nanocomposites based on polybutylene terephthalate (PBT) filled with commercial carbon black (CB) and carbon nanotubes (CNTs) at different relative ratios have been investigated. Field emission scanning electron microscope (FESEM) analysis revealed how a good nanofiller dispersion was obtained both by introducing CB and CNT. Melt flow index measurements highlighted that the processability of the nanocomposites was heavily compromised at elevated filler amounts, and the viscosity percolation threshold was established at 3 wt% for CNTs and between 6 and 10 wt% for CB nanocomposites. Differential scanning calorimetry (DSC) measurements evidenced how the presence of CNT slightly increased the glass transition temperature of the materials, and an increase of 12°C of the crystallization temperature was obtained with a CNT amount of 6 wt%. Also the crystalline fraction was increased upon CNT addition. Electrical resistivity measurements evidenced that the most interesting results were obtained for nanocomposites with a total filler content of 6 wt% and a CNT/CB relative amount equal to 2:1. The synergistic effect obtained with the combination of both nanofillers allowed the achievement of a rapid surface heating through Joule effect even at applied voltages of 2 V. PubDate: 2017-04-21T23:36:28.295175-05: DOI: 10.1002/adv.21833
Authors:Richard Eungkee Lee; Atefe Afsari Ghazi, Taher Azdast, Rezgar Hasanzadeh, Sajjad Mamaghani Shishavan Abstract: In this study, the tensile strength and M-Rockwell hardness of polycarbonate (PC)-nanoalumina composites are investigated under various processing parameters. For this purpose, PC using a twin-screw extruder is melt compounded with nanoparticle of Al2O3 in the presence of styrene-co-maleic anhydride (SMA) as the compatibilizer. Influences of weight percentage of nanoalumina and injection processing parameters including injection pressure and holding pressure (all in four levels) are investigated on tensile and hardness properties of nanocomposite samples using Taguchi's L16 orthogonal array. The scanning electron microscopy (SEM) results reveal that an appropriate distribution of nanoparticles in polymeric matrix is achieved. According to the results, nanoalumina content is the most effective parameter on tensile strength and hardness with about 51% and 85% contribution, respectively. Results indicate that by addition 1.5 wt% of nanoalumina, the tensile strength and hardness of samples increase as much as 4.5% and 11%, respectively. Also, the results reveal that injection pressure and holding pressure are also effective parameters to change hardness and tensile strength. PubDate: 2017-04-17T02:15:50.886738-05: DOI: 10.1002/adv.21832
Authors:Chin Wei Lai; Foo Wah Low, Mun Foong Tai, Sharifah Bee Abdul Hamid Abstract: In the present study, oleic acid (OA)-decorated magnetite nanoparticles (MNPs) were synthesized via in situ co-precipitation method using ammonium hydroxide as a precipitating agent. This study aims to determine the optimum loading amount of OA for improving the MNPs colloidal stability. Based on our results obtained, it was found that the zeta potential values of MNPs increased from −29.8 to −58.1 mV after modification of MNPs with 1.2 wt.% of OA. Indeed, results obtained clearly to show that a maximum colloidal stability of MNPs in a basic medium could be significantly improved. As a result, this resultant colloidal suspension performance was approximately 7 times higher (21 days- high colloidal stability against precipitation and agglomeration) than that of the undecorated MNPs sample (3 days). Based on vibrating sample magnetometer (VSM) analysis, the resultant OA-decorated MNPs exhibited superparamagnetic behavior with slightly lower saturation magnetization (51–69 emu/g) than that of undecorated MNPs sample (80 emu/g) at room temperature. This behavior was attributed to the sufficient carboxylate ions from the outer layer of the bilayer of OA-decorated MNPs, which promoted the high colloidal stability performance. PubDate: 2017-04-11T04:20:43.810624-05: DOI: 10.1002/adv.21829
Authors:Ali Olad; Hamed Gharekhani, Abdolreza Mirmohseni, Ahmad Bybordi Abstract: A novel fertilizer-integrated superabsorbent nanocomposite based on maize bran (MB), acrylic acid (AA), and acrylamide (AAm) was synthesized in an aqueous solution containing montmorillonite (MMT) and NPK fertilizer compound. FTIR spectra indicated that hydroxyl group of the starch molecules in MB composition has participated in grafting reaction with acrylate-based monomers. The swelling behavior of the synthesized hydrogels in different salt and pH solutions was evaluated. Also, the N,N′-methylenebisacrylamide (MBA) and MMT contents were systematically optimized to obtain a highest swelling capacity. Fertilizer release assessments on the NPK-loaded superabsorbent nanocomposite confirmed the effective role of MMT nanolayers in slow-release property of the prepared formulation. Also, the prepared fertilizer formulation exhibited good water retention capacity in soil. As a result, this eco-friendly and economical product can effectively reduce fertilizer loss, improve water utilization efficiency, and prolong irrigation cycles which are benefit for agricultural applications, especially in drought-prone environments. PubDate: 2017-04-06T02:04:23.425843-05: DOI: 10.1002/adv.21825
Authors:Kulmani Mehar; Subrata Kumar Panda Abstract: The deflection behavior of carbon nanotube-reinforced composite plate is investigated numerically using the finite-element method and the result accuracy is established via three-point experimental bending test data. The physical composite panel model is realized with the help of new mathematical model based on the higher order kinematic theory and the responses are computed using the in-house computer code in the MATLAB environment. Further, the efficacy of the current higher order finite-element model has been established by comparing the deflection responses with those of the references, simulation values (ANSYS), and the in-house experimentation including the experimental elastic properties. Finally, the effect of different design parameters, such as aspect ratio, thickness ratio, edge constraints including the types of load on the deflection and stress responses of the composite plate has been studied in detail. PubDate: 2017-04-04T00:35:30.963637-05: DOI: 10.1002/adv.21821
Authors:Raj K. Singh; Aruna Kukrety, Arvind Kumar, Ajay Chouhan, Rakesh C. Saxena, Siddharth S. Ray, Suman L. Jain Abstract: Three copolymeric and two homopolymeric additives were synthesized utilizing the C18 alkyl acrylate (C18Ac) and N,N-dimethylacrylamide (DMAA) monomers. Three additives named as additive 1, additive 2, and additive 3 were synthesized by varying the ratio between C18Ac: DMAA as 1:1, 1:2 and 2:1 respectively by free radical polymerization using AIBN (azobis(isobutyronitrile)) as initiator, whereas additive 4 and additive 5 were the homopolymers of C18Ac and DMAA, respectively. All the synthesized polymers were characterized by FT-IR (fourier transform infrared spectroscopy), NMR (nuclear magnetic resonance), and GPC (gel permeation chromatography) analysis. Performance evaluation of the copolymers as viscosity index improver (VII), pour point depressant (PPD), antiwear, antifriction, and anticorrosion additives in polyol base oil was done by standard methods. As far as the VII, anti-wear, antifriction, and anticorrosive properties are concerned, additive 2 revealed best performance; however, none of the above synthesized additives was found to be suitable for PPD activity. PubDate: 2017-04-03T00:15:25.920243-05: DOI: 10.1002/adv.21826
Authors:Ling Weng; Peihai Ju, Xiaorui Zhang, Lizhu Liu Abstract: With the rapid development of the electronics industry, dielectric materials with a high-dielectric constant are playing an increasingly important role in the performance of electronic devices. In this study, a composite that employed polyvinylidene fluoride (PVDF) as a matrix and four-needle zinc oxide whisker (T-ZnOw) for reinforcement was prepared by casting method. The microstructure and crystallization behavior of the PVDF/T-ZnOw were analyzed by SEM, FT-IR and XRD. Thermal stability and electrical properties of the composites, included the dielectric constant, dielectric loss and electrical breakdown strength, were tested. Analysis on microstructures indicated that the T-ZnOw in composites were uniformly dispersed and some of the whisker's tips had penetrated through the surface of the composites because of the special four-needle structure. Experimental results showed that the addition of T-ZnOw significantly improved the thermal stability of the composites. Broadband dielectric spectroscopy test results showed that the dielectric properties and conductivity of the composites significantly improved with the increase in T-ZnOw contents. The dielectric constant of the composites was 113 at 100 Hz when the T-ZnOw content was 20% at weight content. PubDate: 2017-04-02T23:10:55.496895-05: DOI: 10.1002/adv.21822
Authors:Sema Vural; Turgay Seckin Abstract: In this study, polystyrene- and poly(methyl methacrylate)-grafted polyimide films were prepared successfully using click chemistry and the ATRP technique. Firstly, kapton films were prepared from stepwise thermal imidization of polyamic acid. Surface modification of kapton films was then achieved by chloromethylation followed by the azide decoration process. For surface grafting of kapton films, polystyrene and poly(methyl methacrylate) as alkyne functional polymers were prepared with alkyne and bromine double functionality using propargyl-2-bromopropionate as an initiator. A coupling reaction with azide-decorated PI surface and alkyne functional polymers was achieved via the Huisgen-1,3-dipolar cycloaddition reaction. FTIR spectroscopy, contact angle measurement, thermogravimetry (TG) and differential scanning calorimetry (DSC), energy dispersive X-ray analysis (EDX) and GPC techniques were used to characterize the grafted polyimides. According to the TG analysis, kapton film was modified at the rate of 8% and 10% with PS and PMMA, respectively. PubDate: 2017-03-31T06:35:36.98267-05:0 DOI: 10.1002/adv.21827
Authors:Yao Xiao; Lixia Bao, Xiaowei Fu, Bo Wu, Weibo Kong, Changlin Zhou, Jingxin Lei Abstract: Effect of phase separation on the water resistance of green waterborne polyurethanes was discussed for the first time. Phase separation was studied through the application of dynamic mechanical analysis. Water resistance was characterized by water absorption ratio and water contact angle. The results showed that the phase separation had stronger effect on water resistance compared with the content of hydrophilic segments of green waterborne polyurethanes; higher phase separation degree led to better water resistance even though the content of hydrophilic segments increased. And, fluorescence microscope images of fluorescent dye inside the green waterborne polyurethane films justified this viewpoint. PubDate: 2017-03-27T00:05:33.110582-05: DOI: 10.1002/adv.21818
Authors:Yuzeng Li; Qiao Li, Gesheng Yang, Ruihao Ming, Minmin Yu, Huihui Zhang, Huili Shao Abstract: Poly(l-lactic acid) (PLLA) and poly(d-lactic acid) (PDLA) with various molecular weights (MW) were melt blended in equivalent proportions, and then followed by injection molding to form polylactide stereocomplex (sc-PLA). The crystalline structures, thermal resistance, and mechanical properties of the formed sc-PLA were then investigated in detail. The results showed stereocomplex crystallites (sc) were formed predominantly in all the sc-PLA regardless of the MW of the PLLA or PDLA pellets, and a small amount of homocrystallites (hc) also coexisted in sc-PLA. The MW of PLLA and PDLA pellets displayed significant effects on the crystallinity, thermal resistance, and mechanical properties of sc-PLA. PLLA and PDLA with low and similar MW facilitated the formation of sc, and also improved the onset degradation temperature and Vicat softening temperature of sc-PLA. For a similar degree of crystallinity, high MW was found to be more favorable in improving the thermal performance of sc-PLA. Although sc-PLA prepared from PLLA and PDLA with low MW showed decreased mechanical properties, the mechanical properties of sc-PLA increased with an increase in the MW of the PLLA or PDLA pellet. When PLLA and PDLA pellets with high and similar MW were used, the mechanical properties of sc-PLA could even exceed those of pure PLLA. PubDate: 2017-03-25T01:20:28.841665-05: DOI: 10.1002/adv.21824
Authors:Konrad Terpiłowski; Agnieszka Ewa Wiącek, Małgorzata Jurak Abstract: Wettability properties of polyetheretherketone (PEEK) activated and non-activated by nitrogen plasma have been investigated. Moreover, the PEEK plates were covered with antibacterial chitosan and its wettability properties were also investigated. Surface topography was determined using SEM and optical profilometry and surface composition by FT-IR and XPS. For determination of apparent surface free energy, the hysteresis approach (CAH), acid base (LWAB), and Owens–Wendt (O–W) theory were used. The equilibrium contact angles were calculated from the Tadmor theory and further used for apparent surface energy calculation applying the above-mentioned approaches. Due to the surface plasma activation both the roughness of the surface and the polar component of apparent surface free energy increased. It is shown that nitrogen plasma activation of PEEK surface increases the adhesion of chitosan to the surface due to the combination effect of: (i) the increase in surface roughness, (ii) introducing the polar groups onto the surface. PubDate: 2017-03-25T01:15:49.690434-05: DOI: 10.1002/adv.21813
Authors:Majid Naghibzadeh; Mohsen Adabi, Hamid Reza Rahmani, Mohsen Mirali, Mahdi Adabi Abstract: In this research, the polyvinyl alcohol (PVA) nanofibers through forcespinning process were successfully produced and the effective parameters for predicting nanofibers diameter using artificial neural network (ANN) were investigated. The various parameters of forcespinning process including rotational speed, orifice, distance to the collector, and polymer concentration were designed to produce PVA nanofibers. Scanning electron microscopy (SEM) showed that the produced fibers diameter was in the range of 0.56–1.9 μm. The neural network with four input factors, three hidden layers with 5, 10, 1 nodes in each layers, respectively, and one output layer had the best performance in the testing sets. Moreover, the mean squared error (MSE) and linear regression (R) between observed and predicted nanofibers diameter were about 0.1077 and 0.9387, respectively, demonstrating a suitable performance for the prediction of nanofibers diameter using the selected neural network model. PubDate: 2017-03-23T01:40:31.808248-05: DOI: 10.1002/adv.21817
Authors:Zong-Keng Kuo; Mei-Yen Fang, Tu-Yi Wu, Ted Yang, Hsiang-Wen Tseng, Chih-Chen Chen, Chao-Min Cheng Abstract: Hydrophilic materials have been used in many fields, but have recently garnered growing attention in biomedicine. To promote the development and use of suitable hydrophilic materials for biomedical applications, we used three hydrophilic films of varying hydrophilicity and examined the effects of their hydrophilicity on blood compatibility, protein adsorption, blood clotting time, hemolytic activity, biocompatibility, and cell attachment. Across the spectrum of hydrophilicity examined, no obvious differences in biocompatibility were observed. While high material hydrophilicity was associated with higher hemolytic activity, it still fit the nonhemolytic criteria. Further, higher hydrophilicity decreased protein adsorption and cell attachment, but increased thromboresistance in our blood clotting time assay (~30% higher blood clotting index at 10 min). These results indicate that hydrophilicity increases blood compatibility with regard to thromboresistance, but reduces cellular compatibility (i.e., cell attachment), characteristics that could be exploited for a wide range of potential applications in various fields, such as glucose electrode test strips. PubDate: 2017-03-23T01:30:43.613949-05: DOI: 10.1002/adv.21820
Authors:Muhammad R. Islam; Nadia Isa, Ahmad N. Yahaya, Mohammad Dalour Hossen Beg, Rosli M. Yunus Abstract: Three different processing techniques, extrusion, injection, and compression, were followed to fabricate poly (lactic acid) (PLA) and Moringa oleifera fiber (MOF) based composites. Chopped fibers of length 3–5 mm were used for the extrusion followed by injection molding, whereas long-length fibers (~100 mm) were used for compression molding process. For compression molding, long-length fibers were spread in single and double layers. The interfacial shear strength of the composites was evaluated by fiber pull-out testing. Composites were characterized for fracture behavior and mechanical properties. Additionally, surface morphology was also observed by scanning electron microscopy, whereas crystalline properties were evaluated by X-ray diffraction analysis. Analyses revealed that compression molding with double layers of long-length fibers reinforcement showed better properties than other samples. Tensile strengths of extruded and compression processed samples (double-layered) were 75.5 and 81.1 MPa, which are approximately 33% and 44% higher respectively than neat PLA (56.5 MPa). The crack generation of PLA during applied load was observed and found eliminated for the double-layered sample processed via compression molding. It was found that compression molding with double layer can be considered as easy and less time-consuming method for composite preparation, with nearly 8 wt.% of less fiber consumption compared with extrusion/injection molding. PubDate: 2017-03-23T01:30:37.257271-05: DOI: 10.1002/adv.21823
Authors:Zhongbo Song; Weijun Zhen Abstract: Poly(D-lactic acid) (PDLA) was prepared from D-lactic acid under optimized polymerization conditions of 1 wt% stannous octoate, at 170°C for 12 hr. Poly(L-lactic acid) (PLLA) and its optical isomer, PDLA, were blended to improve the thermal and mechanical properties. Mechanical testing showed an increase in the impact strength of the PLLA/PDLA (0.3 wt%) by 27.6%. SEM showed more shear zones and fibrillation on the composite surfaces, compared withthe PLLA, suggesting high toughness and shock strength. TGA showed the enhanced thermal stability of PLLA composites. The DSC results indicated that the crystallinity of PLLA/PDLA (0.3 wt%) was increased by 54.31%, compared with pure PLLA. Non-isothermal crystallization kinetics suggested the formation of crystal nucleus and the growth rate of PLLA/PDLA (0.3 wt%) increased gradually. Half crystallization time showed a decreasing trend, which could provide a large number of heterogeneous nucleation sites and improved the crystallization rate of PLLA. PubDate: 2017-03-23T01:20:46.477106-05: DOI: 10.1002/adv.21816
Authors:Łukasz Piszczyk; Paulina Kosmela, Michał Strankowski Abstract: Elastic polyurethane foams were produced from two-component polyurethane systems (SPECFLEX NE 113 izocyjanian/NR 816 poliol system—SPC and Elastic MBMarket company system POLYOL ET MB 500/ISO ET MB 800—ET) by using a one-step method. The foams were a graphene nanoplatelets (GNP) in the amount ranging from 1 to 2 wt.%. The effect of the nanofiller on polyurethane matrix was determined by analyzing the chemical structure, static and dynamic mechanical properties, and thermal stability of reinforced foams. The application of the carbon nanofiller resulted in increased density and hardness of the obtained composites. The addition of the nanofiller caused a shift in glass transition temperature toward lower temperature values, and an increase in the Young's modulus, but did not significantly affected the thermal stability of the obtained composites. The research results showed that graphene nanoplatelets nanofiller can be successfully used as a modifier of mechanical and thermal properties in elastic polyurethane foams. PubDate: 2017-03-20T23:51:26.108714-05: DOI: 10.1002/adv.21819
Authors:Jingyao Sun; Daming Wu, Ying Liu, Le Dai, Chong Jiang Abstract: Filling process of micro prism array by isothermal hot embossing in solid-like state (IHESS) with different mold temperature, pressure, and holding time were simulated by DEFORM. Polymethyl methacrylate (PMMA) samples processing by IHESS were tested to validate the numerical simulation results and select the best processing condition. The reliability of simulation was tested quantitatively and qualitatively by comparing the cross-profile and its developing trend separately. It was found that the cross-profiles from the simulations and experiments were in high agreement. The simulated and experimental developing trends of cross-profiles were also the same. These results proved the reliability of simulation and its guidance to the experiments. In order to show the advantages of IHESS, a brief introduction and comparison of IHESS and traditional hot embossing were made. PubDate: 2017-03-20T03:25:38.089871-05: DOI: 10.1002/adv.21815
Authors:Pablo R. Cortez Tornello; Gabriela E. Feresin, Alejandro Tapia, Monika Dzieciuch, Teresita R. Cuadrado, Gustavo A. Abraham Abstract: Poly(ε-caprolactone) microparticles containing embelin (PCLE) are prepared by electrohydrodynamic atomization (EHDA) and emulsion-solvent evaporation techniques. Microparticles are characterized in terms of drug state, drug-loading capacity, encapsulation efficiency, morphology and in vitro release in different mediums. Physicochemical, morphological, and thermal characterization is presented. Kinetic analysis is performed. EHDA microparticles present higher size, surface area, and encapsulation efficiency. The release profiles combine a high initial release, followed by a slow-controlled release stage. Electrosprayed PCLE presented characteristics such as size (3.14 ± 0.05 μm), zeta potential (−49.22 ± 2.88 mV) and release profiles that could be attractive for the development of microcarriers for pulmonary administration of embelin. PubDate: 2017-03-16T23:51:04.51552-05:0 DOI: 10.1002/adv.21814
Authors:Roozbeh Hajiraissi; Yousef Jahani Abstract: It is well-established that rheology can trace structural dynamics and conjectures the forming/formed morphology. The objective of this work is to trace the droplet deformation via conducting fiber spinning process. In this regard, two types of polymer blends Polypropylene (PP)/Polyamide6 (PA6) and Polypropylene/Polytrimethylene terephthalate (PTT) with various ratios (99/1, 94/6, 90/10, and 80/20) were melt-blended on co-rotating twin screw extruder and thereafter, were spun. Scanning electron microscopy (SEM) images represent a droplet and fibrillar morphologies for as-extruded samples and spun blend fibers respectively. Unlike PA6 as dispersed phase, PTT droplets in PP/PTT blend system shows improved spinnability. Linear melt viscoelastic data were gathered by performing rheological approaches in linear region. Conducting frequency sweep at 240°C is revealed a terminal behavior for Gʹ and a Newtonian plateau for η* at low frequencies. However, at 195°C dynamic rheological data pertinent to fibers represent a non-terminal trend for Gʹ and viscosity upturn at low frequencies respectively. These distinguishable characteristics can be considered as spinnability of droplets which reflect fibrillation mechanism, and fibrillar growth can be followed by scanning the viscoelastic responses at low frequency region which enhanced upon fibril growth. According to SEM and rheological test results, PTT, as an engineering plastics, manifests higher capability of forming nano fibrils. PubDate: 2017-02-28T00:45:38.895212-05: DOI: 10.1002/adv.21810
Authors:Muhammad Irfan Fareed Abstract: Tribological performance of polyether ether ketone (PEEK) subjected to various heat treatments namely, annealing, normalizing, water quenching and oil quenching, respectively, after being heated to a temperature of 250°C is evaluated. It is observed that the different cooling rates have a significant effect on the crystallinity of PEEK which is found to be a governing factor in determining its mechanical and tribological properties. Micro hardness testing and ball-on-disk wear test results showed that both hardness and wear resistance increased with an increase in the crystallinity of PEEK. It is observed that the annealed samples showed the highest wear resistance when compared with the water-quenched samples which is attributed to the increased crystallinity in the case of the annealed samples. PubDate: 2017-02-25T02:15:31.329504-05: DOI: 10.1002/adv.21812
Authors:Gaoyi Xie; Jie Yu, Shuhao Qin, Jing Sun, Zhao Yang, Liangqiang Wei, Yubi Ji, Wentao He, Guomin Xu Abstract: To achieve a selective localization of nanoparticles in multilayered two-component polymer blends, an intentional two-step process, first pre-compounding and then co-extruding, was employed to prepare multilayered high-density polyethylene (HDPE)/polyethylene-grafted maleic anhydride (PE-g-MAH)/organic montmorillonite (OMMT)-polyamide 6 (PA6) nanocomposites. The dispersion of OMMT was evaluated by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results showed that the localization of OMMT was tunable with different content of PE-g-MAH. By comparing the localization of OMMT in a single-layered nanocomposite with that in the multilayered nanocomposites, as well as by theoretically calculating wetting coefficients of the multilayered nanocomposites, the migration mechanism of OMMT was revealed. As demonstrated by differential scanning calorimetry (DSC), transmission rate measurement and tensile test, the selective localization of OMMT in the multilayered nanocomposites could increase crystallinity degree of the two-polymer components, enhancing oxygen barrier property and tensile strength of the nanocomposties. PubDate: 2017-02-21T23:40:32.462813-05: DOI: 10.1002/adv.21811
Authors:Xuezhen Sui; Wenying Zhou, Lina Dong, Zijun Wang, Xiangrong Liu, Anning Zhou, Jiangtao Cai, Qingguo Chen Abstract: Aluminum (Al) reinforced silicone rubber (SR) composites were prepared, and the effects of the content, particle size, shape, and surface modification of Al particles on the dielectric properties and thermal conductivity of the Al/SR were investigated. Dielectric permittivity, dissipation factor and thermal conductivity of the Al/SR increase with increasing the filler content. The dissipation factors still remain at a low level at high filler content because of the insulating alumina shell on the surface of core Al. Decrease in particle size and surface modification of Al can increase the dielectric permittivity and thermal conductivity of the Al/SR composites. Compared with spherical Al/SR, the flaky Al/SR composites present higher dielectric permittivity and thermal conductivity. Dielectric permittivity and thermal conductivity of the Al/carbon fiber (CF)/SR composites reach 72.1 and 2.01 W/m K at 75 wt% of the total filler content, respectively, suggesting that the ternary composites has potential applications in electromechanical actuators because of their high dielectric permittivity and thermal conductivity but low dissipation factor, and good elasticity. PubDate: 2017-02-19T23:41:29.107038-05: DOI: 10.1002/adv.21809
Authors:Muhammad Hanif; Ghulam Abbas Abstract: Aim of the present work was to develop alginate–pectin rafts by using box behnken design to provide symptomatic relief from gastroesophageal reflux disorders by forming floating gel or raft on the top of gastric contents. Sodium alginate and pectin were used as raft-forming polymers, sodium bicarbonate as gas-generating substance, and calcium carbonate for generation of calcium ions. Physical test of all compressed formulations were within pharmacopoeial limits. Effect of pH of medium on raft formation was observed by placing the formulation in different pH mediums. Raft was characterized by their strength, weight, volume, resilience, reflux resistance, thickness, buffering capacity, neutralizing capacity, floating lag time (FLT) and total floating time (TFT). Fourier transform infrared (FTIR) spectroscopy was performed to check the interaction between the polymers and other excipients. Raft was effectively formed at pH 1.2. Raft strength, reflux resistance, and thickness of optimized formulation APR15 were 9.71 ± 0.013 g, 2670 ± 0.987 g, and 5.1 ± 0.045 cm, respectively. Raft resilience for the APR15 was found to be greater than 480 min. TFT of APR15 was greater than 8 hr with 50 s FLT. Buffering and neutralizing capacity were 12.70 ± 1.21 meq and 7.0 ± 0.34 meq, respectively. FTIR spectra showed no interactions between sodium alginate, pectin, and other excipients. This study demonstrated that alginate–pectin rafts are suitable for the treatment of gastro-esophageal reflux disorders. PubDate: 2017-02-16T23:25:47.782154-05: DOI: 10.1002/adv.21808
Authors:Ekwipoo Kalkornsurapranee; Wanida Yung-Aoon, Bencha Thongnuanchan, Anoma Thitithammawong, Charoen Nakason, Jobish Johns Abstract: In this work, we present an easy way to vulcanize natural rubber using glutaraldehyde as a cross-linking agent. The effect of poly(methyl methacrylate) (PMMA) grafting along with cross-linking of natural rubber on the mechanical, thermal, and oil resistance properties was studied. The main objective of this work was to improve the properties of cured natural rubber (NR) based on glutaraldehyde (GA) as a curing agent by using modified NR. Cured NR-g-PMMA with different grafting levels were studied systematically and compared with cured natural rubber. A remarkable improvement in the properties of natural rubber was obtained by grafting PMMA. Higher tensile strength without much reduction in elongation at break can be achieved by curing NR-g-PMMA with glutaraldehyde. The natural rubber grafted with PMMA and subsequently cured with glutaraldehyde as a cross-linking agent was found to be a useful technique for improving the properties of natural rubber products. PubDate: 2017-02-10T04:46:16.620411-05: DOI: 10.1002/adv.21806
Authors:Ahmad Zarei; Azam Jalali-Arani Abstract: Nanocomposites based on (organoclay [OC]/butadiene rubber [BR]/natural rubber [NR]) containing different ratio of (sulfur/accelerator [dibenzothiazyl disulfide (MBTS)] or N-Oxydiethyl-2-benzthiazolsulfenamid (NOBS)) were prepared. Evaluation of the vulcanization characteristics showed that the curing system and the type of the used accelerator affected the impact of the OC on the scorch and cure times. The crosslink density and the percentage of polysulfide bonds of the compounds were enhanced by using OC. X-ray diffraction (XRD) analysis showed that the type of curing system and the used accelerator affected the network structure as well as the expansion of the interlayer space of the OC. In nanocomposites with less crosslink density and less polysulfide bonds, greater expansion of the OC interlayer spaces was observed. The use of the OC and its effect on the level of crosslink density and percent of polysulfide bonds affected the tensile properties and abrasion loss of the samples. PubDate: 2017-02-10T04:40:37.221495-05: DOI: 10.1002/adv.21805
Authors:Bo Wu; Weibo Kong, Kai Hu, Xiaowei Fu, Jingxin Lei, Changlin Zhou Abstract: A new interfacial modifier containing silicon and phosphorus has been developed to improve the flame retardancy and mechanical properties of ethylene-vinyl acetate (EVA)/alumina trihydrate (ATH) composites. The EVA/ATH composites were prepared via blending EVA pellets with different kinds of ATH particles. The results showed a synergistic effect of phosphorus-containing silane coupling agent (DOSA) and ATH particles on the flame retardancy of EVA composites. When compared with pure EVA of 19.1, the limiting oxygen index (LOI) value was increased to 31.4. This was the result of the formation of a charred layer and the enhanced compatibilities between inorganic particles and polymer matrix. The experimental results also showed that the modified ATH particles by using synthesized DOSA led to an increase in mechanical properties. The improvement on the mechanical and thermal properties of EVA composites was mostly attributed to the better dispersion ability of the modified ATH particles in the polymer matrix and a synergistic effect between the DOSA and ATH particles. The char-formation ability of EVA composites has also been analyzed and the synthesized DOSA has shown a positive effect. PubDate: 2017-02-06T05:21:09.632957-05: DOI: 10.1002/adv.21804
Authors:Shun-Hua Jiang; Jun-Xiong Wu, Jing Zhou, Qiu-Feng Lü Abstract: Self-assembled poly(N-methylaniline) (PNMA) microspheres were prepared in a facile way by an unstirred polymerization of N-methylaniline monomers with ammonium persulfate as an oxidizing agent at different temperatures. The polymers were characterized by FTIR and UV-vis spectroscopy, SEM, TEM and wide-angle X-ray diffraction. Furthermore, adsorption property of PNMA microspheres for silver ions from aqueous solution was investigated by batch experiments. The results revealed that PNMA showed a high-performance adsorption for silver ions by chelation and redox reaction. The maximum adsorption capacity was up to 2.460 g/g for silver ions on PNMA microspheres prepared at 0°C, at an initial silver ion concentration of 160 mmol/L at 25°C for 48 hr. The adsorption process fits the pseudo-second-order kinetics and Freundlich isotherm models. Moreover, the PNMA microspheres exbihit high reductive performances for Au(III) and Pd(II) ions. Therefore, the PNMA microspheres have great potential application in removal and recovery of metal ions from industrial wastewater. PubDate: 2017-02-02T01:27:02.091507-05: DOI: 10.1002/adv.21807
Authors:Jun-Jun Chen; Shi-Hao Qin, Qun-Chen Lv, Dong-Liang Shi, Xu-Min Zheng, Hui-Jun Wu, Hua-Kun Huang, Liu-Guang Lian, Fu-An He, Kwok-Ho Lam Abstract: Polystyrene-block-polybutadiene-block-polystyrene triblock copolymer (SBS) has the potential to be used as a dielectric elastomer for actuator, sensor, energy harvesting, and so on, but its low dielectric constant and thermal conductivity seriously limit this application. In this study, novel exfoliated graphite nanoplates (xGNPs)/SBS composites were prepared by a solution-blending method using N,N-dimethylformamide and tetrahydrofuran as co-solvents. Wide-angle X-ray diffraction measurement confirms that xGNPs have been incorporated into SBS. Furthermore, the result of scanning electron microscopy shows that xGNPs disperse well in the SBS matrix. The effects of xGNPs on the dielectric constant and thermal conductivity of the resultant xGNPs/SBS composites were investigated. The dielectric constant at 1,000 Hz significantly increased from 2.72 for pure SBS to 15.96 and 40.94 for xGNPs/SBS composite containing 1.19 and 1.27 vol.% of xGNPs, respectively. Moreover, the thermal conductivity of the xGNPs/SBS composite containing 1.27 vol.% of xGNPs has been improved from 0.18 to 0.41 W/m·K in comparison with that of pure SBS. PubDate: 2017-01-27T06:55:37.269004-05: DOI: 10.1002/adv.21797
Authors:Cagatay Yilmaz; Mehmet Yildiz, Yusuf Menceloglu Abstract: We present an experimental study on the microcapsule-based semi-intrinsic self-healing behavior of low viscosity epoxy resin used in Resin Transfer Molding (RTM) process. The microcapsules containing RTM epoxy resin are prepared using in situ polymerization of urea-formaldehyde. Single type of microcapsules with six different agitation rates is prepared, resulting in microcapsules with a mean diameter ranging from 52 to 202 μm. The thermal characteristics of each microcapsule batch are investigated using Differential Scanning Calorimetry (DSC) and Simultaneous Thermal Analysis (STA). In addition to thermal characterization tools, Fourier Transform Infrared Spectroscopy (FTIR) is also used as a qualitative technique to determine the composition of microcapsules. The mechanical properties of the self-healing specimen such as Mode-I fracture toughness and flexure strength are assessed by a universal testing machine, and the obtained results are compared with the findings in literature. PubDate: 2017-01-25T00:05:31.228962-05: DOI: 10.1002/adv.21802
Authors:Yu Shang; Fuyuan Ding, Jian Liu, Ling Xiao, Hongbing Deng, Yumin Du, Xiaowen Shi Abstract: Polymeric core–shell microspheres have been widely applied in dual-drug release system for their convenience to treat diseases through multiple therapies. In this contribution, acrylamide-modified chitin (AMC)/chitosan (CS) core–shell microspheres were prepared by a coaxial electrospray method under mild conditions. The dimension of the microspheres and thickness of the layer can be delicately controlled by changing the feed rate of spray solutions and the applied voltage. The core–shell structure of the microspheres was characterized by Fourier transform infrared spectra (FT-IR), scanning electron microscope (SEM), and stereo fluorescence microscope. To investigate the dual-drug release behavior of the core–shell microspheres, small molecular FITC-dextran and macromolecular dextran blue 2000 were chosen as model drugs. The release rate of small molecular FITC-dextran was higher than macromolecular dextran blue 2000 regardless of the location of FITC-dextran in the microspheres. The biocompatibility, biodegradability, and dual-drug release behavior of the core–shell microspheres endow it with potential applications in combination therapies. PubDate: 2017-01-24T00:00:51.091649-05: DOI: 10.1002/adv.21795
Authors:Wei Ma; Lin Li, Jing Li, Xuehong Ren, Zhi-Guo Gu, Tung-Shi Huang Abstract: Inorganic–organic composites have received considerable attention due to their combined properties. In this study, a N-halamine precursor poly[5,5-dimethyl-3-(3′-triethoxysilylpropyl)-hydantoin] (PSPH) was synthesized and used for the production of inorganic–organic hybrid particles after reacting with nano-TiO2 by a sol–gel process. The hybrid particles were characterized by FT-IR, XRD, and TGA-DTG. After chlorinated in the dilute sodium hypochlorite solution, antibacterial Cl-PSPH-TiO2 nanoparticles (NPS) could be obtained and used for production of polyvinyl alcohol (PVA) composite membranes. The synthesized PSPH-TiO2/PVA composite membranes were characterized by SEM, FT-IR, XRD, and TGA-DTG. Meanwhile, antibacterial property, UV light stability, mechanical properties, and storage stability of the composite membranes were tested. The antibacterial composite membranes with Cl-PSPH-TiO2 could inactivate 99.97% of Staphylococcus aureus (3.03 logs) and 100% of Escherichia coli O157:H7 (6.12 logs) within 30 min. The antibacterial composite membranes also showed good UV light stability, regeneration ability, and excellent storage stability. PubDate: 2017-01-16T00:25:39.514046-05: DOI: 10.1002/adv.21798
Authors:Massimiliano Barletta; Patrizia Moretti, Elisa Pizzi, Michela Puopolo, Silvia Vesco, Vincenzo Tagliaferri Abstract: In recent time, the quest for renewable materials for the development of packaging items is constantly increasing. The class of polylactic acids (PLAs) is the most promising one, although a broader scale commercial expansion of these polymers cannot leave unceasing enhancement of their functional properties aside, especially toughness and thermal stability. Similarly, continuous innovation in prototyping competitive easy-route solutions for material processing is another key to successful industrial applications of PLAs. In this respect, this study deals with the design and formulation of innovative custom-built PLAs for injection and compression molding, which are compostable, suitable for food contact, and characterized by a good compromise of mechanical properties and thermal resistance. Therefore, a commercial grade PLA was modified by reactive compounding extrusion with maleic anhydride (MAH)-grafted PLA (PLA-MA) and glycidyl methacrylate (GMA)-grafted PLA (PLA-GMA) and micro-lamellar talc. Material structure and thermal response of the compounds were evaluated by differential scanning calorimetry (DSC) and Fourier transform-infrared spectroscopy (FTIR). The experimental findings show that material structure and, especially, crystallization of the PLA can be controlled by fine-tuning the compound formulation. In addition, achievement of the appropriate crystallization degree in the polymer can lead to compostable composite materials with good thermal stability. Accordingly, the custom-built PLA formulations feature the potential to expand significantly the fields of application of compostable biopolymers, thus posing a valid alternative to both durable not compostable bioplastics and conventional plastics in injection and compression molding process. PubDate: 2017-01-13T06:15:43.567683-05: DOI: 10.1002/adv.21803
Authors:Shoumin Wang; Peng Zhao, Ningyang Li, Xuguang Qiao, Zhixiang Xu Abstract: In this study, a new sensor of molecularly imprinted solid-phase extraction coupled with flow-injection chemiluminescence for the detection of monocrotophos was fabricated. The molecularly imprinted polymer was synthesized by the bulk polymerization, using monocrotophos, methacrylic acid, and ethylene glycol dimethacrylate as the template molecule, functional monomer, and cross-linker, respectively. The adsorption and recognition ability of the imprinted polymer toward monocrotophos was investigated. Factors influencing preconcentration of the analytes and sensitivity of the method were optimized. Under the optimal conditions, the chemiluminescence intensity was linearly proportional to the concentration of monocrotophos range from 0.0023 to 10 mg/L, and the limit of detection of the method was 0.001 mg/L. Rape (Brassica napus) and pakchoi (Brassica rapa subsp. chinensis) samples spiked with monocrotophos at three levels were analyzed by the developed method with recoveries between 89.3% and 105.9%. This method was successfully applied to the determination of monocrotophos in spinach samples, and the results were verified by gas chromatography method. PubDate: 2017-01-12T23:35:39.76993-05:0 DOI: 10.1002/adv.21799
Authors:Akhtar J. Siddiqa; Somnath Maji, Koel Chaudhury, Basudam Adhikari Abstract: In this study, the surface of low-density polyethylene (LDPE) was functionalized with maleic anhydride (MA) using solution grafting method in the presence of benzoyl peroxide (BPO), an initiator. The surface chemistry of the grafted LDPE was characterized using different characterization tools. The effect of MA grafting for analysis of bulk properties such as the change in mechanical strength and thermal properties was studied. Further, the nanoindentation study was performed to analyze the surface mechanical property after MA grafting. Biocompatibility studies were carried out using NIH-3T3 cells through MTT assay test. FTIR analysis revealed the presence of carboxylic groups on LDPE surface. The contact angle value was found to be 44 ± 3°, which confirms the development of hydrophilicity in LDPE. Cell viability was found>75% in MTT assay. These results suggested that the prepared hydrophilic LDPE is a potential candidate for biomedical applications and surface coatings with other polar polymer. PubDate: 2017-01-12T23:25:36.506674-05: DOI: 10.1002/adv.21800
Authors:Dody Ariawan; Muhamad S. Salim, Razaina Mat Taib, Mohammad Z. Ahmad Thirmizir, Zainal A. Mohammad Ishak Abstract: Nonwoven kenaf fiber (KF) mat-reinforced unsaturated polyester resin composites were exposed to a natural weathering environment for 12 months. The composites were prepared using vacuum-assisted resin transfer molding (RTM). Prior to molding, the KF mat was treated by immersing it in 6% NaOH solution for 3 hrs and by heating it at 140°C for 10 hrs, respectively. The influences of weathering exposure on the composites with respect to the different treatments were investigated using flexural properties, fracture toughness, Fourier transform infrared, thermal stability, color and scanning electron microscopy analyses. Natural weathering reduced the flexural and fracture toughness due to damage to composite structures, the formation of microcracks on the sample surface, discoloration, and chemical content alteration. A relatively better durability in terms of flexural properties was exhibited by alkali-treated KF composites, although poor durability in fracture toughness was observed due to the improved fiber–matrix adhesion. PubDate: 2017-01-12T00:36:05.283216-05: DOI: 10.1002/adv.21801
Authors:Hossein Behniafar; Mojtaba Yazdi Abstract: In this article, multi-walled carbon nanotubes (CNT's) were coated by poly(tetramethylene oxide) (PTMO) soft layer. PTMO was used for preparing segmented polyurethane (PU) films as well. PTMO-grafted CNT was utilized for loading into the PTMO-based segmented PU films in three different contents, i.e., 0.2, 0.4, and 0.8 wt.%. All PU-CNT nanocomposites were characterized by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques. The resulting nanocomposites were also investigated by thermogravimetric analysis (TG/DTG), differential thermal analysis (DTA), and dynamic mechanical thermal analysis (DMTA). DTMA results showed a significant increase in the storage moduli, especially at temperatures PubDate: 2017-01-03T01:01:43.921134-05: DOI: 10.1002/adv.21796
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