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 Colloid and Polymer ScienceJournal Prestige (SJR): 0.597 Citation Impact (citeScore): 2Number of Followers: 6      Hybrid journal (It can contain Open Access articles) ISSN (Print) 0303-402X - ISSN (Online) 1435-1536 Published by Springer-Verlag  [2469 journals]
• Green preparation and thermal properties of shape-stabilized
paraffin/CS/SiO2 composite for phase change energy storage

Abstract: In order to make up for the performance defects of a single packaging material, the new shape-stabilized paraffin/CS/SiO2 composite phase change materials (paraffin/CS/SiO2 ss-CPCMs) were prepared by using paraffin as the phase change material and CS/SiO2 as the composite packaging materials. The synthesis process is green and pollution-free. The microstructure, network structure, thermal stability, phase transformation properties, and shape stability of the composites were characterized by FE-SEM, FTIR, TGA, and DSC, etc. The results indicated that the synthesized paraffin/CS/SiO2 ss-CPCMs with network structure had strong shape stability and thermal stability. Good sealing performance could be maintained at 65 °C and 95 °C. When the amount of TEOS was 4 mL, it had higher latent heat of phase change and minimal heat loss, which was only 0.89 J/g. The paraffin/CS/SiO2 ss-CPCMs prepared in this research provided a new method for preparing green, non-toxic, and harmless phase change materials with stable shapes. Graphical abstract
PubDate: 2022-05-21

• Rheology and microscopy analysis of polymer–surfactant complexes

Abstract: Polyelectrolytes are a fascinating type of polymeric substance that is increasingly being employed in sophisticated industrial formulations. Combining these polymers with a surfactant results in a solution with unique behaviour and formation due to a mixture of hydrophobic and hydrophilic interactions at both the large (polymer) and tiny (surfactant) molecular scales. In this study, we look at the literature on polyelectrolyte–surfactant complexes on a molecular level, using mostly rheology and TEM to cover all the elements that go into producing them and the interplay that exists between distinct molecular interacting types. This study was assembled from over 300 sources to investigate a wide range of rich polymer\surfactant complex systems with a variety of uses, some of which had a basic purpose of understanding the effects of alteration on the behaviour of these systems. Gene therapy, drug administration, oil recovery, and nanoparticle manufacturing are among the target applications of surfactant polymer systems, according to the literature. Most of the published literature focuses on changing the type of surfactant (e.g., Gemini or single-chain surfactant), changing the system (exchanging polymer or surfactant), functionalizing surfactant\polymer, making the surfactant or polymer less hydrophobic for better binding, and then studying and exploring the formed complexes using a variety of techniques. Graphical abstract Rich rheological behaviour of polymer\surfactant system
PubDate: 2022-05-18

• Adsorption behaviors of dyes on a biodegradable
gelatin/chitosan/β-cyclodextrin hydrogel from an aqueous solution

PubDate: 2022-05-18

• Nucleating effect of boron nitride nanotubes on poly(lactic acid)
crystallization

Abstract: Abstract Poly(lactic acid) (PLA) is a well-known biodegradable and biocompatible polymer. However, its poor crystallization ability restricts its broad applications. In this work, PLA/boron nitride nanotubes (BNNTs) nanocomposites were prepared by melt mixing. From either the melt or the glassy state, the effect of BNNTs on the nonisothermal and isothermal crystallization behavior of PLA was investigated by using differential scanning calorimetry (DSC) as well as polarized optical microscopy (POM). It was found that a small amount (0.25 wt%) of BNNTs could enhance both nonisothermal melt and cold crystallization of PLA remarkably. The Avrami equation was employed to analyze the calorimetric characterization of the isothermal crystallization behavior. It was found that the Avrami exponent of PLA crystallization was almost not changed in the presence of BNNTs, suggesting that both the melt and cold crystallization mechanism is unchanged with the addition of BNNTs. This investigation reveals that BNNTs are effective nucleator of PLA in substituting for carbon nanotubes (CNTs), when colorless products are demanded.
PubDate: 2022-05-18

• Miscibility, crystallization, mechanical, and rheological properties of
poly (L-lactic acid)/poly(vinyl acetate) blends

Abstract: Abstract Herein, poly(L-lactic acid) (PLA) and poly(vinyl acetate) (PVAc) with high molecular weight were melt compounded to prepare blends with improved mechanical and rheological properties. Dynamic mechanical analysis (DMA) suggested that PLA and PVAc were miscible. Rheological properties indicated that the addition of PVAc improved the viscoelasticity of PLA melt, resulting in the suppression of cold crystallization of the blends. Isothermal melt crystallization behaviors revealed the addition of PVAc decreased crystallization rate, whereas did not change the crystallization mechanism. Unexpectedly, increases of 38%, 21%, and 55% were achieved in the modulus, yield strength, and elongation at break of blend with 20 wt % PVAc content compared to neat PLA. What is more practical is that the PLA/PVAc blends prepared by simple melt blending process showed the combination of improved stiffness, strength, ductility, and melt strength, which helps to meet the performance and process requirements of PLA in various fields.
PubDate: 2022-05-17

• Structure formation and electrophysical properties of poly(vinylidene
fluoride-hexafluoropropylene) copolymer films at low-temperature solution
crystallization

Abstract: Abstract The structural and electrophysical characteristics of poly (vinylidene fluoride-hexafluoropropylene) copolymer films with hexafluoropropylene content 8.3 mol%, obtained by low-temperature crystallization from various solvents, have been investigated. X-ray diffraction data indicate that the films crystallized mainly in the α-phase. When acetone is used as a solvent, the degree of crystallinity is the lowest due to the rapid escape of solvent molecules from solution. IR spectroscopic data showed that the amorphous phase of such films is enriched with T3GT3G− isomers. This is accompanied by an increase in their high-voltage conductivity. Despite the crystallization mainly in nonpolar α-phase, a domain structure was recorded in the films by piezo force microscopy. Surface structuring processes, accompanied by the displacement of certain attachment chain defects into the surface, have been recorded using IR spectroscopy. The presence of such intrachain defects is confirmed and characterized by high-resolution 19F NMR.
PubDate: 2022-05-17

• Preparation of polyelectrolyte complex nanoparticles with tunable and
narrow size distributions by template polymerization

Abstract: Abstract Template polymerization (i.e., polymerization of monomers along a macromolecular template) provides a scalable method for preparing colloidal polyelectrolyte complexes (PECs) with narrow size distributions. To our knowledge, however, the formation of sub-50-nm PECs through template polymerization has generally required the use of block copolymers or involved covalent crosslinking. Here, we report a one-step synthesis of such PEC nanoparticles through a simple free-radical polymerization of an anionic monomer (acrylic acid) on a polycationic poly(allylamine) (PAH) template. The self-assembly of the resulting poly(acrylic acid) (PAA) with the PAH generated narrowly dispersed particles with average sizes ranging between roughly 20 and 400 nm, which could be readily tuned by adjusting the parent solution concentration. At particle-forming compositions, most of the PAH became incorporated into the PECs, thus indicating high particle yields. Once assembled, these particles remained stably dispersed throughout a monthlong stability experiment when stored at low ionic strengths. When stored in ≥ 40 mM NaCl solutions, however (unless the particles were prepared in an excess of PAH), the dispersions underwent at least partial agglomeration. Collectively, these findings show template polymerization to be an effective technique for generating nanoparticles (including those with sub-50-nm dimensions) with tunable, narrowly dispersed sizes and high yields.
PubDate: 2022-05-10

• Preparation and structural regulation of macroporous agarose microspheres
for highly efficient adsorption of giant biomolecules

Abstract: Abstract Macroporous agarose microspheres for bioseparation of giant biomolecules were prepared by a surfactant micellar swelling method, and the effects of preparation conditions on both particle size and its distribution and pore structure were systematically studied. Under the optimal condition with a surfactant amount of 20% (v/v), Triton X-100 to sodium dodecyl sulfate ratio (SDS) of 5:1 (w/w), an oil-absorbing-swelling time of 2.5 h, and a stirring speed of 250 rpm, macroporous agarose microspheres were successfully prepared, characterized by inverse size exclusion chromatography. Distribution coefficient (Kd) of dextran probes for agarose microspheres after being cross-linked was almost the same as that for agarose microspheres before being cross-linked. Inverse size exclusion chromatography results showed that macroporous agarose microspheres had a pore size distribution of more than 40 nm or even close to 60 nm, while that of conventional microspheres was no more than 40 nm. Macroporous agarose microspheres functionalized with diethylaminoethyl groups had a higher adsorption capacity and faster adsorption rate for hepatitis B surface antigen (HBsAg) compared with both commercial DEAE-agarose chromatographic media and conventional DEAE-agarose microspheres which were both based on agarose microspheres prepared using a traditional method. Confocal laser scanning microscopy results showed that macroporous agarose microspheres had a good binding ability to HBsAg, and this antigen completely entered the inside of the microspheres. Compared with conventional agarose chromatographic media, the macroporous agarose media combined macromolecular proteins more quickly and fully, having wider applications in the field of purification of giant biomolecules.
PubDate: 2022-05-10

• Structure/property relationship of semicrystalline polymers during tensile
deformation: a molecular dynamics approach

Abstract: Molecular dynamics (MD) simulation with an ab initio numerical model is conducted to study the structure–property relationship of semicrystalline polymers during uniaxial deformation. The effects of chain length, temperature, and strain rate on mechanical properties are discussed. The influences of microstructural evolution such as bond length, entanglement density, and chain orientation are also studied quantitatively. The temperature will greatly affect the chain conformation in amorphous domains, and the results revealed that the interaction of amorphous and crystalline domains played a crucial role during stretching. Accordingly, the yielding of semicrystalline polymers follows different mechanisms at temperatures above and below Tg. A melt-recrystallization scheme is observed during yielding at higher temperatures, while destruction of crystal structures is observed at lower temperatures at the yield point. The correlated effects of different temperatures and strain rates on mechanical properties are examined. This work is part of our efforts to develop a digital twin of a real experiment for efficient optimization of polymer material properties. Graphical abstract
PubDate: 2022-05-06

• Diimide hydrogenation of NBR latex using different zinc ions catalytic
system

Abstract: The zinc ion is used as a catalyst to effectively replace the traditional copper ion catalyst to participate in the redox reaction of hydrazine hydrate and hydrogen peroxide to generate diimide to selectively hydrogenate the carbon–carbon double bonds in the nitrile butadiene rubber (NBR) latex to prepare hydrogenated NBR (HNBR). The optimized zinc ion catalytic hydrogenation system was obtained through orthogonal design experiment screening. Among them, the hydrogenation of NBR latex with zinc chloride as a catalyst can obtain HNBR-ZnCl2 products with high hydrogenation degree (90.58%), high thermal stability, and high regularity. Using zinc ions as a catalyst instead of copper ions can effectively improve the damage of copper ions remaining in the hydrogenated product on the thermal-oxidative aging resistance performance of rubber. Compared with HNBR hydrogenated by copper ions, HNBR hydrogenated by zinc ion catalysts has better thermal-oxidative aging resistance performance. Graphical abstract
PubDate: 2022-05-02

• Temperature-regulated elasticity and multifunctionality in n-alkyl
methacrylate ester-based ternary gels: optimizing adsorption and
pH/temperature dual sensitivity

Abstract: An attempt was made to correlate the gelation temperature with elasticity and pH/temperature dual sensitivity of n-alkyl methacrylate ester-based cationic gels. Ternary gels were prepared by free-radical crosslinking of HPMA, DMAEMA, and GMA in water at fixed monomer and crosslinker concentrations, while gel preparation temperature Tprep was varied from − 18 to 60 °C. The structure and physical properties of ternary gels were fully characterized using thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray diffraction (XRD). Tprep has been shown to be an effective independent variable to adjust both macroscopic and microscopic properties of ternary gels as desired. Gelation temperature dependence of swelling and compressive elasticity was investigated. Ternary gels synthesized at 5 °C showed maximum swelling capacity. The equilibrium swelling ratio increased first slightly up to 5 °C and then decreased continuously with increasing Tprep. This trend indicated that swelling is influenced by properties of both crosslinking region and the main constituent amorphous region. In swollen state, elastic modulus of gels changed from 0.9 to 108 kPa and increased 120 times as Tprep decreased from 60 to − 18 °C. Terpolymer gels showed pH-sensitive swelling characteristic of cationic DMAEMA monomer and exhibited high swelling ratio in acidic solutions induced by electrostatic repulsion between quaternary amine groups. The swelling ratio decreased due to hydrophobic effect of the alkyls when environmental pH is higher than 7.7. Regardless of Tprep, the gels gradually contracted as swelling temperature increased from 25 to 75 °C. Flory–Huggins interaction parameter $$\chi$$ ranged from 0.4005 to 0.5358 and increased with the degree of intermolecular hydrophobic interactions. The effectiveness of ternary gels for removing methyl orange from aqueous solution was tested, and the results showed that the gels prepared under low-temperature conditions were promising for removing anionic dyes. The adsorption was spontaneous and found to be a multistep process with surface adsorption followed by intraparticle diffusion. This knowledge will aid the future design of n-alkyl methacrylate ester-based ternary gels as an effective adsorbent for dye removal from wastewater and pharmaceutical preparations. Graphical abstract Amine group-containing ternary gels were prepared by free radical crosslinking polymerization of HPMA, DMAEMA and GMA at different gel preparation temperature.
PubDate: 2022-05-01

• Crystallization behavior and structure of metallocene polyethylene with
long-chain branch

Abstract: The investigations of the branching chain have influence on the crystallization behaviors and structures in metallocene polyethylene (mPE) as compared to the Ziegler–Natta polyethylenes that have grown significantly since the introduction of metallocene catalytic polymerization in industrial applications. A zirconium dichloride complex, three intermediates, and methylaluminoxane were used as metallocene catalysts for the polymerization of ethylene to obtain the mPEs. The structures of the mPEs were characterized by 13C nuclear magnetic resonance (13C-NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and dynamic rheology method. The results on the crystallization of the mPEs showed master curve features and indicated fractal topology of the long-chain branch. The conflicting result obtained from the 13C NMR and rheology is due to the long-chain fractal structure. The successive self-nucleation and annealing (SSA) was used to characterize the length of crystallizable methylene sequence length (MSL) methylene sequence. It was found that the lamellar thickness calculated via Thomson-Gibbs equation exhibits two scaling relationships with MSL related to the molecular weight of the polyethylene chain entanglements $$\left({M}_{\mathrm{e}}\right)$$ . Graphical abstract
PubDate: 2022-05-01

• Impact of the various buffer solutions on the temperature-responsive
properties of POEGMA-grafted brush coatings

Abstract: The effect of temperature and buffer solutions with different pH (often used in biomedical applications) on the behavior of POEGMA brush coatings, synthesized without incorporated functional groups, was for the first time studied in details using water contact angle (CA) measurements and atomic force microscopy (AFM). Thermal response of grafted brush-coatings based on poly(oligo(ethylene glycol) methacrylate)s (POEGMA)s is driven by lower critical solution temperature (LCST) phenomenon. Obtained CA and AFM results suggest strong impact of the buffer solutions on the values of LCST transition and contact angle ranges, as well as on coatings morphology. In turn, ellipsometry data reflect penetration of salt ions from buffer solutions into brush-coatings. In contrast to “typical” behavior of POEGMA coatings in water, different mechanisms available below LCST in the buffer solutions destroy hydrated layers surrounding POEGMA macromolecules leading to their collapse. Graphical abstract
PubDate: 2022-05-01

• Facile fabrication of high-performance PA66/MWNT nanocomposite fibers

Abstract: Abstract Carbon nanotubes (CNTs) are promising polymer-strengthening materials; however, it is difficult to achieve the even distribution of CNTs in polymer matrixes and strong interfacial interactions between CNTs and polymeric chains. In the present work, multi-walled carbon nanotubes (MWNTs), carboxylic multi-walled carbon nanotubes (MWNTs-COOH), amino multi-walled carbon nanotubes (MWNTs-NH2), and hydroxylated multi-walled carbon nanotubes (MWNTs-OH) were added as reinforcements to the polyamide 66 (PA66) matrix. CNTs were dispersed in the PA66 matrix by a twin-rotor high-speed mixing extruder at 800 rpm. Chips were melted spun and two-step stretched to fabricate nanocomposite fibers. The microstructure and properties of nanocomposite fibers were investigated. It was found that MWNTs-COOH were well dispersed in the PA66 matrix. PA66/MWNTs-COOH nanocomposite fibers exhibited the best mechanical properties. The tensile strength and Young’s modulus of PA66/0.3 wt% MWNTs-COOH nanocomposite fibers were ~ 907 MPa and ~ 5.92 GPa, respectively, which were 22.2% and 4.8% higher than those of pure PA66 fibers, respectively.
PubDate: 2022-05-01

• Spectroscopic analysis and nuclear magnetic resonance for silver
nanoparticles synthesized with trans-resveratrol and cis-resveratrol

Abstract: Abstract The synthesis of silver nanoparticles with polyphenolic molecules (AgResvNPs) is important due to potential applications as nanocarriers of resveratrol. Silver nanoparticles were synthesized with trans-3,5,4′-trihydroxystilbene (resveratrol) and irradiated under UV light. Further AgResvNPs were characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), selected area electron diffraction (SAED), UV–Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy with surface-enhanced Raman scattering (SERS), nuclear magnetic resonance (NMR), zeta potential, and dynamic light scattering (DLS) and study of aggregation kinetic and colloidal stability for this system in water and s-DMEM and evaluate the antioxidant capacity with total phenols count assay. Ultraviolet light irradiation promotes the synthesis of AgResvNPs and modifies the conformational structure of resveratrol. NMR confirmed these changes structurally in the molecule. Applications in SERS are an important application of this system.
PubDate: 2022-05-01

• Diffusiophoresis of a mercury drop

Abstract: Abstract The general expression is obtained for the diffusiophoretic mobility of a mercury drop in an electrolyte concentration gradient. On the basis of the obtained general mobility expression, an approximate analytic mobility expression which is correct to the second order of the drop zeta potential is derived.
PubDate: 2022-05-01

• A study of effects of the non-DLVO interparticle interactions on
aggregation rate

Abstract: Abstract A key issue for theoretically predicting the aggregation rate of colloidal particles is to appropriately describe interparticle interactions. The recent progress in the study of interaction potential between suspended particles is the introduction of the structured-layer potential (SLP). However, the published data still show the degree of approximation of the theoretical expectation varies with the particle size, which means that the relevant parameters of SLP may not be constant independent of particle size. In this study, the approximation degree of the theoretical model to the experimental data of aggregation rates of particles with different sizes under different interparticle interaction parameters was compared. The results demonstrated that, in all cases of rapid and slow homo-aggregation and hetero-aggregation, the theoretical value of aggregation rates using particle-size-dependent SLP parameters are much closer to the experimental value than that using particle-size-independent SLP parameters.
PubDate: 2022-05-01

• Fabrication of methacrylated casein/alginate microspheres crosslinked by
UV light coupled with Ca2+ chelation for pH-sensitive drug delivery

PubDate: 2022-05-01

• Polymer nanoarchitectonics for synthetic vesicles with human
erythrocyte-like morphology transformation

Abstract: Abstract This paper describes that synthetic polymer vesicles undergo a human erythrocyte-like morphology transformation in response to temperature changes. The normally biconcave discoid erythrocytes, i.e., the discocytes, are transformed into various shapes by their environmental stresses. Poly(methacrylic acid)-block-poly(n-butyl methacrylate-random-methacrylic acid), PMAA-b-P(BMA-r-MAA), produced spherocyte-like spherical vesicles with a dimple by the photopolymerization-induced self-assembly in a 70% aqueous methanol solution. The dimpled vesicles transformed into echinocyte-like crenate vesicles when heated in the solution with a vesicle concentration of 5.68 g/L. Field emission scanning electron microscopy demonstrated that the crenation was based on expansion by the component copolymers in being freed from the vesicle surface. An increase in the vesicle concentration to 9.94 g/L transformed the spherical vesicles into stomatocyte-like cup-shaped vesicles. The transformation involved two mechanisms; one is the principal pathway of a single membrane invagination followed by perforation at the dimple, and the other is a pathway of simultaneous double invaginations followed by membrane coupling and fusion. Light scattering studies revealed that the transformations were reversible and repeatable. Furthermore, a decrease in the methanol content to 60% in the solution increased the number of discocyte-like and knizocyte-like vesicles among the stomatocyte-like vesicles. A further decrease in the content to 50% produced a slight number of stomato II-acanthocyte-like and torocyte-like vesicles. A still lower content below 40% prevented the vesicles from transforming even at 50 °C. These findings indicate that the synthetic polymer vesicles are helpful for a better understanding of the intrinsic properties of the erythrocyte membrane on a molecular basis.
PubDate: 2022-05-01

• Investigation of a hydrophobically associating polymer’s temperature and
salt resistance for fracturing fluid thickener

Abstract: Abstract Polyacrylamide (HPAM) is commonly used as a thickener in water-based fracturing fluids due to its good solubility and thickening ability. However, drawbacks such as the formation of high temperature and high salinity in oil and gas production currently limit its use as a thickening agent for fracturing fluids. To solve this problem, a hydrophobic associating polymer, DSAM (acrylamide/2-acrylamido-2-methylpropanesulfonic acid/acrylic acid/hydrophobic monomer AMD-12), with a good temperature and salt resistance was synthesized via complex initiated polymerization. The molecular structure of the synthesized polymer DSAM was confirmed using IR and 1H NMR. The water solubility, thickening properties, and salt resistance of DSAM polymers were investigated. The results showed that the DSAM polymer solution’s apparent viscosity initially decreased with the addition of NaCl. However, as the salt concentration further increased, the DSAM polymer solution’s polarity also increased, as well as the hydrophobic association between molecules, resulting in a denser hydrophobic association network structure and an increase in the apparent viscosity of the polymer solution. The viscoelasticity test revealed that as the salt concentration increased, the viscoelastic polymer solution increased after initially decreasing, which was consistent with previous salt tolerance test results. Additionally, it exhibited superior temperature resistance, shear tolerance, and shear recovery capabilities compared with conventional HPAM. Meanwhile, the DSAM polymer can be completely broken down in the industry-standard time without residue. The benefits of DSAM polymers include salt thickening, high-temperature resistance, and thorough gel breaking. Thus, it has huge potential as a thickening agent for temperature-tolerant and salt-resistant fracturing fluid.
PubDate: 2022-04-07

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