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Publisher: Hindawi   (Total: 338 journals)

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Showing 1 - 200 of 338 Journals sorted alphabetically
Abstract and Applied Analysis     Open Access   (Followers: 3, SJR: 0.343, CiteScore: 1)
Active and Passive Electronic Components     Open Access   (Followers: 7, SJR: 0.136, CiteScore: 0)
Advances in Acoustics and Vibration     Open Access   (Followers: 42, SJR: 0.147, CiteScore: 0)
Advances in Aerospace Engineering     Open Access   (Followers: 56)
Advances in Agriculture     Open Access   (Followers: 10)
Advances in Artificial Intelligence     Open Access   (Followers: 16)
Advances in Astronomy     Open Access   (Followers: 41, SJR: 0.257, CiteScore: 1)
Advances in Bioinformatics     Open Access   (Followers: 18, SJR: 0.565, CiteScore: 2)
Advances in Biology     Open Access   (Followers: 11)
Advances in Chemistry     Open Access   (Followers: 28)
Advances in Civil Engineering     Open Access   (Followers: 48, SJR: 0.539, CiteScore: 1)
Advances in Computer Engineering     Open Access   (Followers: 4)
Advances in Condensed Matter Physics     Open Access   (Followers: 11, SJR: 0.315, CiteScore: 1)
Advances in Decision Sciences     Open Access   (Followers: 3, SJR: 0.303, CiteScore: 1)
Advances in Electrical Engineering     Open Access   (Followers: 42)
Advances in Electronics     Open Access   (Followers: 90)
Advances in Emergency Medicine     Open Access   (Followers: 12)
Advances in Endocrinology     Open Access   (Followers: 6)
Advances in Environmental Chemistry     Open Access   (Followers: 8)
Advances in Epidemiology     Open Access   (Followers: 8)
Advances in Fuzzy Systems     Open Access   (Followers: 5, SJR: 0.161, CiteScore: 1)
Advances in Geology     Open Access   (Followers: 19)
Advances in Geriatrics     Open Access   (Followers: 6)
Advances in Hematology     Open Access   (Followers: 13, SJR: 0.661, CiteScore: 2)
Advances in Hepatology     Open Access   (Followers: 2)
Advances in High Energy Physics     Open Access   (Followers: 22, SJR: 0.866, CiteScore: 2)
Advances in Human-Computer Interaction     Open Access   (Followers: 21, SJR: 0.186, CiteScore: 1)
Advances in Materials Science and Engineering     Open Access   (Followers: 31, SJR: 0.315, CiteScore: 1)
Advances in Mathematical Physics     Open Access   (Followers: 7, SJR: 0.218, CiteScore: 1)
Advances in Medicine     Open Access   (Followers: 3)
Advances in Meteorology     Open Access   (Followers: 24, SJR: 0.48, CiteScore: 1)
Advances in Multimedia     Open Access   (Followers: 2, SJR: 0.173, CiteScore: 1)
Advances in Nonlinear Optics     Open Access   (Followers: 6)
Advances in Numerical Analysis     Open Access   (Followers: 7)
Advances in Nursing     Open Access   (Followers: 33)
Advances in Operations Research     Open Access   (Followers: 12, SJR: 0.205, CiteScore: 1)
Advances in Optical Technologies     Open Access   (Followers: 4, SJR: 0.214, CiteScore: 1)
Advances in Optics     Open Access   (Followers: 5)
Advances in OptoElectronics     Open Access   (Followers: 6, SJR: 0.141, CiteScore: 0)
Advances in Orthopedics     Open Access   (Followers: 8, SJR: 0.922, CiteScore: 2)
Advances in Pharmacological Sciences     Open Access   (Followers: 8, SJR: 0.591, CiteScore: 2)
Advances in Physical Chemistry     Open Access   (Followers: 12, SJR: 0.179, CiteScore: 1)
Advances in Polymer Technology     Open Access   (Followers: 14, SJR: 0.299, CiteScore: 1)
Advances in Power Electronics     Open Access   (Followers: 35, SJR: 0.184, CiteScore: 0)
Advances in Preventive Medicine     Open Access   (Followers: 6)
Advances in Public Health     Open Access   (Followers: 25)
Advances in Regenerative Medicine     Open Access   (Followers: 3)
Advances in Software Engineering     Open Access   (Followers: 11)
Advances in Statistics     Open Access   (Followers: 5)
Advances in Toxicology     Open Access   (Followers: 2)
Advances in Tribology     Open Access   (Followers: 14, SJR: 0.265, CiteScore: 1)
Advances in Urology     Open Access   (Followers: 12, SJR: 0.51, CiteScore: 1)
Advances in Virology     Open Access   (Followers: 7, SJR: 0.838, CiteScore: 2)
AIDS Research and Treatment     Open Access   (Followers: 2, SJR: 0.758, CiteScore: 2)
Analytical Cellular Pathology     Open Access   (Followers: 3, SJR: 0.886, CiteScore: 2)
Anatomy Research Intl.     Open Access   (Followers: 3)
Anemia     Open Access   (Followers: 5, SJR: 0.669, CiteScore: 2)
Anesthesiology Research and Practice     Open Access   (Followers: 15, SJR: 0.501, CiteScore: 1)
Applied and Environmental Soil Science     Open Access   (Followers: 18, SJR: 0.451, CiteScore: 1)
Applied Bionics and Biomechanics     Open Access   (Followers: 7, SJR: 0.288, CiteScore: 1)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 14)
Archaea     Open Access   (Followers: 3, SJR: 0.852, CiteScore: 2)
Autism Research and Treatment     Open Access   (Followers: 31)
Autoimmune Diseases     Open Access   (Followers: 3, SJR: 0.805, CiteScore: 2)
Behavioural Neurology     Open Access   (Followers: 9, SJR: 0.786, CiteScore: 2)
Biochemistry Research Intl.     Open Access   (Followers: 7, SJR: 0.437, CiteScore: 2)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 11, SJR: 0.419, CiteScore: 2)
BioMed Research Intl.     Open Access   (Followers: 4, SJR: 0.935, CiteScore: 3)
Biotechnology Research Intl.     Open Access   (Followers: 1)
Bone Marrow Research     Open Access   (Followers: 2, SJR: 0.531, CiteScore: 1)
Canadian J. of Gastroenterology & Hepatology     Open Access   (Followers: 6, SJR: 0.867, CiteScore: 1)
Canadian J. of Infectious Diseases and Medical Microbiology     Open Access   (Followers: 6, SJR: 0.548, CiteScore: 1)
Canadian Respiratory J.     Open Access   (Followers: 1, SJR: 0.474, CiteScore: 1)
Cardiology Research and Practice     Open Access   (Followers: 10, SJR: 1.237, CiteScore: 4)
Cardiovascular Therapeutics     Open Access   (Followers: 1, SJR: 1.075, CiteScore: 2)
Case Reports in Anesthesiology     Open Access   (Followers: 11)
Case Reports in Cardiology     Open Access   (Followers: 7, SJR: 0.219, CiteScore: 0)
Case Reports in Critical Care     Open Access   (Followers: 12)
Case Reports in Dentistry     Open Access   (Followers: 7, SJR: 0.229, CiteScore: 0)
Case Reports in Dermatological Medicine     Open Access   (Followers: 2)
Case Reports in Emergency Medicine     Open Access   (Followers: 15)
Case Reports in Endocrinology     Open Access   (Followers: 2, SJR: 0.209, CiteScore: 1)
Case Reports in Gastrointestinal Medicine     Open Access   (Followers: 2)
Case Reports in Genetics     Open Access   (Followers: 1)
Case Reports in Hematology     Open Access   (Followers: 8)
Case Reports in Hepatology     Open Access   (Followers: 1)
Case Reports in Immunology     Open Access   (Followers: 5)
Case Reports in Infectious Diseases     Open Access   (Followers: 5)
Case Reports in Medicine     Open Access   (Followers: 2)
Case Reports in Nephrology     Open Access   (Followers: 5)
Case Reports in Neurological Medicine     Open Access   (Followers: 1)
Case Reports in Obstetrics and Gynecology     Open Access   (Followers: 10)
Case Reports in Oncological Medicine     Open Access   (Followers: 2, SJR: 0.204, CiteScore: 1)
Case Reports in Ophthalmological Medicine     Open Access   (Followers: 3)
Case Reports in Orthopedics     Open Access   (Followers: 6)
Case Reports in Otolaryngology     Open Access   (Followers: 7)
Case Reports in Pathology     Open Access   (Followers: 7)
Case Reports in Pediatrics     Open Access   (Followers: 7)
Case Reports in Psychiatry     Open Access   (Followers: 16)
Case Reports in Pulmonology     Open Access   (Followers: 3)
Case Reports in Radiology     Open Access   (Followers: 11)
Case Reports in Rheumatology     Open Access   (Followers: 8)
Case Reports in Surgery     Open Access   (Followers: 12)
Case Reports in Transplantation     Open Access  
Case Reports in Urology     Open Access   (Followers: 11)
Case Reports in Vascular Medicine     Open Access  
Case Reports in Veterinary Medicine     Open Access   (Followers: 5)
Child Development Research     Open Access   (Followers: 18, SJR: 0.144, CiteScore: 0)
Chinese J. of Engineering     Open Access   (Followers: 2, SJR: 0.114, CiteScore: 0)
Chinese J. of Mathematics     Open Access  
Chromatography Research Intl.     Open Access   (Followers: 5)
Complexity     Hybrid Journal   (Followers: 6, SJR: 0.531, CiteScore: 2)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2, SJR: 0.403, CiteScore: 1)
Computational Intelligence and Neuroscience     Open Access   (Followers: 13, SJR: 0.326, CiteScore: 1)
Contrast Media & Molecular Imaging     Open Access   (Followers: 3, SJR: 0.842, CiteScore: 3)
Critical Care Research and Practice     Open Access   (Followers: 12, SJR: 0.499, CiteScore: 1)
Current Gerontology and Geriatrics Research     Open Access   (Followers: 9, SJR: 0.512, CiteScore: 2)
Depression Research and Treatment     Open Access   (Followers: 15, SJR: 0.816, CiteScore: 2)
Dermatology Research and Practice     Open Access   (Followers: 3, SJR: 0.806, CiteScore: 2)
Diagnostic and Therapeutic Endoscopy     Open Access   (SJR: 0.201, CiteScore: 1)
Discrete Dynamics in Nature and Society     Open Access   (Followers: 5, SJR: 0.279, CiteScore: 1)
Disease Markers     Open Access   (Followers: 1, SJR: 0.9, CiteScore: 2)
Economics Research Intl.     Open Access   (Followers: 1)
Education Research Intl.     Open Access   (Followers: 19)
Emergency Medicine Intl.     Open Access   (Followers: 9, SJR: 0.298, CiteScore: 1)
Enzyme Research     Open Access   (Followers: 5, SJR: 0.653, CiteScore: 3)
Evidence-based Complementary and Alternative Medicine     Open Access   (Followers: 23, SJR: 0.683, CiteScore: 2)
Game Theory     Open Access   (Followers: 1)
Gastroenterology Research and Practice     Open Access   (Followers: 2, SJR: 0.768, CiteScore: 2)
Genetics Research Intl.     Open Access   (Followers: 1, SJR: 0.61, CiteScore: 2)
Geofluids     Open Access   (Followers: 5, SJR: 0.952, CiteScore: 2)
Hepatitis Research and Treatment     Open Access   (Followers: 6, SJR: 0.389, CiteScore: 2)
Heteroatom Chemistry     Open Access   (Followers: 3, SJR: 0.333, CiteScore: 1)
HPB Surgery     Open Access   (Followers: 7, SJR: 0.824, CiteScore: 2)
Infectious Diseases in Obstetrics and Gynecology     Open Access   (Followers: 5, SJR: 1.27, CiteScore: 2)
Interdisciplinary Perspectives on Infectious Diseases     Open Access   (Followers: 1, SJR: 0.627, CiteScore: 2)
Intl. J. of Aerospace Engineering     Open Access   (Followers: 74, SJR: 0.232, CiteScore: 1)
Intl. J. of Agronomy     Open Access   (Followers: 6, SJR: 0.311, CiteScore: 1)
Intl. J. of Alzheimer's Disease     Open Access   (Followers: 11, SJR: 0.787, CiteScore: 3)
Intl. J. of Analytical Chemistry     Open Access   (Followers: 22, SJR: 0.285, CiteScore: 1)
Intl. J. of Antennas and Propagation     Open Access   (Followers: 11, SJR: 0.233, CiteScore: 1)
Intl. J. of Atmospheric Sciences     Open Access   (Followers: 22)
Intl. J. of Biodiversity     Open Access   (Followers: 3)
Intl. J. of Biomaterials     Open Access   (Followers: 4, SJR: 0.511, CiteScore: 2)
Intl. J. of Biomedical Imaging     Open Access   (Followers: 3, SJR: 0.501, CiteScore: 2)
Intl. J. of Breast Cancer     Open Access   (Followers: 14, SJR: 1.025, CiteScore: 2)
Intl. J. of Cell Biology     Open Access   (Followers: 4, SJR: 1.887, CiteScore: 4)
Intl. J. of Chemical Engineering     Open Access   (Followers: 9, SJR: 0.327, CiteScore: 1)
Intl. J. of Chronic Diseases     Open Access   (Followers: 1)
Intl. J. of Combinatorics     Open Access   (Followers: 1)
Intl. J. of Computer Games Technology     Open Access   (Followers: 10, SJR: 0.287, CiteScore: 2)
Intl. J. of Corrosion     Open Access   (Followers: 10, SJR: 0.194, CiteScore: 1)
Intl. J. of Dentistry     Open Access   (Followers: 7, SJR: 0.649, CiteScore: 2)
Intl. J. of Differential Equations     Open Access   (Followers: 8, SJR: 0.191, CiteScore: 0)
Intl. J. of Digital Multimedia Broadcasting     Open Access   (Followers: 5, SJR: 0.296, CiteScore: 2)
Intl. J. of Electrochemistry     Open Access   (Followers: 8)
Intl. J. of Endocrinology     Open Access   (Followers: 4, SJR: 1.012, CiteScore: 3)
Intl. J. of Engineering Mathematics     Open Access   (Followers: 6)
Intl. J. of Food Science     Open Access   (Followers: 5, SJR: 0.44, CiteScore: 2)
Intl. J. of Forestry Research     Open Access   (Followers: 3, SJR: 0.373, CiteScore: 1)
Intl. J. of Genomics     Open Access   (Followers: 2, SJR: 0.868, CiteScore: 3)
Intl. J. of Geophysics     Open Access   (Followers: 5, SJR: 0.182, CiteScore: 1)
Intl. J. of Hepatology     Open Access   (Followers: 5, SJR: 0.874, CiteScore: 2)
Intl. J. of Hypertension     Open Access   (Followers: 8, SJR: 0.578, CiteScore: 1)
Intl. J. of Inflammation     Open Access   (SJR: 1.264, CiteScore: 3)
Intl. J. of Inorganic Chemistry     Open Access   (Followers: 3)
Intl. J. of Manufacturing Engineering     Open Access   (Followers: 2)
Intl. J. of Mathematics and Mathematical Sciences     Open Access   (Followers: 3, SJR: 0.177, CiteScore: 0)
Intl. J. of Medicinal Chemistry     Open Access   (Followers: 6, SJR: 0.31, CiteScore: 1)
Intl. J. of Metals     Open Access   (Followers: 7)
Intl. J. of Microbiology     Open Access   (Followers: 8, SJR: 0.662, CiteScore: 2)
Intl. J. of Microwave Science and Technology     Open Access   (Followers: 3, SJR: 0.136, CiteScore: 1)
Intl. J. of Navigation and Observation     Open Access   (Followers: 20, SJR: 0.267, CiteScore: 2)
Intl. J. of Nephrology     Open Access   (Followers: 1, SJR: 0.697, CiteScore: 1)
Intl. J. of Oceanography     Open Access   (Followers: 7)
Intl. J. of Optics     Open Access   (Followers: 7, SJR: 0.231, CiteScore: 1)
Intl. J. of Otolaryngology     Open Access   (Followers: 3)
Intl. J. of Partial Differential Equations     Open Access   (Followers: 2)
Intl. J. of Pediatrics     Open Access   (Followers: 6)
Intl. J. of Peptides     Open Access   (Followers: 2, SJR: 0.46, CiteScore: 1)
Intl. J. of Photoenergy     Open Access   (Followers: 3, SJR: 0.341, CiteScore: 1)
Intl. J. of Plant Genomics     Open Access   (Followers: 4, SJR: 0.583, CiteScore: 1)
Intl. J. of Polymer Science     Open Access   (Followers: 25, SJR: 0.298, CiteScore: 1)
Intl. J. of Population Research     Open Access   (Followers: 4)
Intl. J. of Quality, Statistics, and Reliability     Open Access   (Followers: 17)
Intl. J. of Reconfigurable Computing     Open Access   (SJR: 0.123, CiteScore: 1)
Intl. J. of Reproductive Medicine     Open Access   (Followers: 4)
Intl. J. of Rheumatology     Open Access   (Followers: 4, SJR: 0.645, CiteScore: 2)
Intl. J. of Rotating Machinery     Open Access   (Followers: 2, SJR: 0.193, CiteScore: 1)
Intl. J. of Spectroscopy     Open Access   (Followers: 8)
Intl. J. of Stochastic Analysis     Open Access   (Followers: 3, SJR: 0.279, CiteScore: 1)
Intl. J. of Surgical Oncology     Open Access   (Followers: 1, SJR: 0.573, CiteScore: 2)
Intl. J. of Telemedicine and Applications     Open Access   (Followers: 5, SJR: 0.403, CiteScore: 2)
Intl. J. of Vascular Medicine     Open Access   (SJR: 0.782, CiteScore: 2)
Intl. J. of Zoology     Open Access   (Followers: 2, SJR: 0.209, CiteScore: 1)
Intl. Scholarly Research Notices     Open Access   (Followers: 211)
ISRN Astronomy and Astrophysics     Open Access   (Followers: 7)
J. of Addiction     Open Access   (Followers: 14)
J. of Advanced Transportation     Hybrid Journal   (Followers: 13, SJR: 0.581, CiteScore: 1)
J. of Aerodynamics     Open Access   (Followers: 13)

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Similar Journals
Journal Cover
International Journal of Polymer Science
Journal Prestige (SJR): 0.298
Citation Impact (citeScore): 1
Number of Followers: 25  

  This is an Open Access Journal Open Access journal
ISSN (Print) 1687-9422 - ISSN (Online) 1687-9430
Published by Hindawi Homepage  [338 journals]
  • Cure Kinetics of an Optical Polythiourethane with Amine Catalyst by IR
           Analysis

    • Abstract: An optical polythiourethane based on m-xylylene diisocyanate (XDI) and 4-mercaptomethyl-3,6-dithia-1,8-octanedithiol (BES) has been studied. Triethylamine was adopted as a catalyst, and the solid-state isothermal cure reaction was carried out using FTIR spectroscopy, in the temperature range of 75°C-105°C. The -NCO absorption band of XDI was used to monitor the conversion of diisocyanate into polythiourethane. The reaction rate enhanced with an increase in the content of the catalyst, and the gel time determined by swelling test was shorter for the system with higher catalyst content. Kinetic parameters were calculated from the infrared spectrum data, and the results showed that the curing reaction of polythiourethane accords with first-order kinetic characteristics. The activation parameters obtained from the evaluation of kinetic data were ,, and . The observed negative entropy of activation value supported the formation of a transition state in the cure reaction.
      PubDate: Mon, 16 Sep 2019 16:05:02 +000
       
  • Preparation of Nano-SiO2/Carbon Fiber-Reinforced Concrete and Its
           Influence on the Performance of Oil Well Cement

    • Abstract: In view of the oilfield well thin oil layer, small gap, and side drilling cementing after perforating and subsequent stimulation caused by the cement ring embrittlement (i.e., secondary channeling), the preparation of nano-SiO2/carbon fiber-reinforced body and its influence on the performance of oil well cement were studied to improve the cement stone and enhance its adaptability to oil well pressure in this study. Carbon fibers were treated by liquid phase oxidation and a coupling agent, and the “grafting to” was used to bond nano-SiO2 and carbon fibers. It was found that the mechanical properties of the enhanced cement stone are far better than those of the blank cement stone. The compressive strength and tensile strength of the enhanced oil well cement stone were increased by 25% and 26%, respectively, compared with those of the blank oil well cement sample; the modulus of elasticity was reduced by 29%. Finally, the enhancement mechanism of SiO2/carbon fiber reinforcement on cement stone was explored by infrared, scanning electron microscopy, and XRD patterns. The deflection effect, pull-out effect, and bridging effect of crack were obtained.
      PubDate: Sun, 15 Sep 2019 00:06:32 +000
       
  • Study of Synthesis and Flocculation Properties of New Modified Hydrophobic
           Organic Polymer P(AM-DM-DMC12)

    • Abstract: A new modified hydrophobic organic polymer P(AM-DM-DMC12) is synthesized by free radical polymerization of three monomers in aqueous solution using a REDOX initiator system. Its structure is characterized by FT-IR and 1H-NMR, the effect of reaction conditions on the product is studied, and the flocculation performance and mechanism are discussed with the aim of wastewater turbidity and COD removal rate. The results showed that the synthesized compounds accorded with the target structure, and the optimum synthetic conditions are as follows: the molar ratio of AM, DM, and DMC12 is 4 : 1 : 1, total mass fraction of monomer is 35%, the mass fraction of redox initiator is 0.06%, and the molecular weight of P(AM-DM-DMC12) is . Moreover, the flocculation effect of P(AM-DM-DMC12) is obviously better than that of PAM, and it has the advantages of short flocculation time, low dosage, and wide application range of pH and has a good industrial application value and prospect.
      PubDate: Mon, 09 Sep 2019 08:05:15 +000
       
  • Review on Hybrid Carbon/Flax Composites and Their Properties

    • Abstract: Numerous research studies are carried out in order to investigate various properties and implement the potential of hybrid carbon/flax composites for technical applications. This review aims to present a summary of materials and manufacturing techniques, which are currently used for the fabrication of the carbon/flax composites, and describe the reported tensile, bending, impact, and damping properties of the resulting hybrid materials as well as the attempts to model some of these properties.
      PubDate: Sun, 08 Sep 2019 00:06:10 +000
       
  • Thermal and Flammability Properties of Kenaf/Recycled Carbon Filled with
           Cardanol Hybrid Composites

    • Abstract: In this paper, hybrid composites were fabricated by using kenaf and recycled carbon with a cashew nut shell liquid (CNSL) derivative known as cardanol as the matrix by a compression molding technique. In this work, we look for the effect of recycled carbon weight loading (15%, 25%, and 35%) on the thermal properties of kenaf/cardanol composites while maintaining the total fiber loading of 50 wt%. TGA, DSC, DMA, and flammability UL 90 HB properties of the specimens were studied. The results indicate that cardanol improved the thermal stability of kenaf and hybridization with recycled carbon also further improved the thermal stability of the specimens. The flammability UL 90 HB test determines the flame retardancy property of all specimens.
      PubDate: Thu, 05 Sep 2019 13:05:41 +000
       
  • Protective Effect of Polygonatum sibiricum Polysaccharides on Apoptosis,
           Inflammation, and Oxidative Stress in Nucleus Pulposus Cells of Rats with
           the Degeneration of the Intervertebral Disc

    • Abstract: Objective. Polygonatum sibiricum polysaccharide (PSP) has antioxidant activity, immune enhancement, and other biological properties. However, the effect of PSP on intervertebral disc degeneration has not been reported. In this study, we mainly investigated the effect of PSP on the apoptosis, inflammation, and oxidative stress of nucleus pulposus cells (NPCs) during the process of intervertebral disc degeneration. Methods. A rat NPC model induced by H2O2 was constructed. The CCK8 method was used to measure the effects of PSP on the apoptosis of rat NPCs induced by H2O2. The effects on the activity of SOD and content of MDA were also determined. The rat model of intervertebral disc degeneration was treated with PSP for 1 month, and the mRNA expression levels of IL-1β, COX2, iNOS, Col2α1, Col10α1, and MMP3 were measured by qPCR in the tissue of intervertebral disc. NPCs from the degenerated intervertebral discs were separated, and the cell viability was measured by the CCK8 method. The contents of SOD and MDA in NPCs were determined as well. Results. PSP significantly reduced the apoptosis of NPCs induced by H2O2, significantly increased the SOD content, and decreased the content of MDA in H2O2-induced NPCs. The expression level of IL-1β, COX2, and iNOS in the rat model with intervertebral disc degeneration was significantly downregulated after 1 month of PSP treatment. PSP treatment increased the expression of Col2α1 type and significantly decreased the expression of Col10α1 type collagen and MMP3 in rats with disc degeneration. PSP treatment significantly reduced NPC apoptosis and increased its SOD content and reduced MDA content, which is consistent with the results from cell-level experiments. Conclusion. PSP can effectively reduce the apoptosis, inflammation, and oxidative stress of H2O2-induced NPCs in rats with intervertebral disc degeneration and mitigate the progression of intervertebral disc degeneration, which has the potential to be developed as new drugs for the treatment of intervertebral disc degeneration.
      PubDate: Thu, 05 Sep 2019 13:05:39 +000
       
  • Effects of Size of Zinc Borate on the Flame Retardant Properties of
           Intumescent Coatings

    • Abstract: This paper is aimed at assessing the fire retardancy and thermal stability of intumescent flame retardant (IFR) containing ammonium polyphosphate (APP), pentaerythritol (PER), and melamine (MEL). Zinc borate (ZB) was added at the loading of 2%, 4%, 6%, 8%, 10%, and 12% by weight of IFR. The sizes of investigated ZB fall in 3 ranges: 1-2 μm, 2-5 μm, and 5-10 μm. The performance of APP/PER/MEL was investigated by using thermogravimetry analysis (TGA), cone calorimeter test, Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy, and energy-dispersive spectrometry. The results obtained from the above experiments show that the incorporation of ZB can improve the fire protection performance. A 77% decrease in total smoke production and 84.6% decrease in total heat release were achieved for the addition of 2 wt% ZB (2-5 μm) in the IFR coating. TGA results indicate an increased amount of char residue. Compared to the control IFR coating, the char residue of IFR containing 2 wt% ZB (2-5 μm) has increased approximately 1.5-fold, 10-fold, and 25-fold, at 600°C, 700°C, and 800°C, respectively. The effective char formation results in excellent smoke suppression. Regarding smoke suppression performance, the order for smoke density is IFR/ZB (2-5 μm) 
      PubDate: Mon, 02 Sep 2019 00:07:13 +000
       
  • Synthesis and Properties of Bionanocomposites of
           Polyhydroxybutyrate-Polylactic Acid Doped with Copper and Silver
           Nanoparticles

    • Abstract: Global pollution has caused a real interest on the use of biodegradable materials to the sustainable development. PLA and PHB are interesting materials due to their properties and their biodegradability, and their blends in different ratios are proposed in this study; also, Ag and Cu nanoparticles were incorporated to observe possible enhances and advantages on it. Blends were characterized through FTIR, TGA, tensile, and DMA tests. Theoretically, results obtained were coherent; FTIR spectra showed a characteristic band (around 1740 cm-1) corresponding to the carbonyl bond at different intensities for each blend which is an evidence of the polymers. Likewise, TGA results showed different marked decomposition points (except for PLA/PHB 70/30), which is another indicative parameter. Regarding tensile tests, PLA/PHB/nanoparticle (NP) blends showed higher Young modulus value action improving exponentially some properties and they can act as a powerful complementary component even in small amounts. The NPs incorporated exhibited clustering due to the blending process with ranges from 93.24 nm for Cu to 123.71 nm for Ag.
      PubDate: Wed, 28 Aug 2019 05:05:10 +000
       
  • Heating Characteristics of Films Prepared with Polymer-Graphite Composites

    • Abstract: Heating films were prepared by using poly(methyl methacrylate) and polybutadiene composites containing graphite. The heating film was prepared by casting the as-made polymer composite on the PET film. Copper electrodes were attached to both ends of the as-prepared film, and the heating characteristics of the film were analyzed while applying the DC voltage. The electrical conductivity and the heating temperature of the heating films depended on the size, the structure, the content, and the dispersion characteristics of the graphite in the composite. The electrical resistance of the heating film was controlled to adjust the heating temperature of the film. The relationship between the physical/chemical structure and the heating characteristics of the composite film was studied by measuring the heating temperature as functions of film thickness and resistance by using an infrared thermal imaging camera. The lower the film resistance, the higher the heating temperature of the film. The surface temperature was uniform throughout the film.
      PubDate: Mon, 19 Aug 2019 11:05:17 +000
       
  • Functionalized Multiwalled Carbon Nanotube-Reinforced Polyimide Composite
           Films with Enhanced Mechanical and Thermal Properties

    • Abstract: Polyimide- (PI-) based nanocomposites containing the 4,4-diaminodiphenyl ether- (ODA-) modified multiwalled carbon nanotube (MWCNT) filler were successfully prepared. The PI/MWCNTs-ODA composite films exhibit high thermal conductivity and excellent mechanical property. The optimal value of thermal conductivity of the PI/MWCNTs-ODA composite film is 0.4397 W/mK with 3 wt.% filler loading, increased by 221.89% in comparison with that of the pure PI film. In addition, the tensile strength of the PI/MWCNTs-ODA composite film is 141.48 MPa with 3 wt.% filler loading, increased by 20.74% in comparison with that of the pure PI film. This work develops a new strategy to achieve a good balance between the high thermal conductivity and excellent mechanical properties of polyimide composite films by using functionalized carbon nanotubes as an effective thermal conductive filler.
      PubDate: Wed, 14 Aug 2019 00:07:31 +000
       
  • Effect of Radix Hedysari Polysaccharide on Glioma by Cell Cycle Arrest and
           TNF-α Signaling Pathway Regulation

    • Abstract: Objective. To investigate the possible development of radix hedysari polysaccharide as an antiglioma drug, we studied the effect of radix hedysari polysaccharide on glioma cells in vitro and the growth of glioma in nude mice and on the phagocytosis of macrophages in nude mice with glioma. Methods. The effect of radix hedysari polysaccharide on the growth of glioma was studied based on U251 cell line in vitro. The effect of radix hedysari polysaccharide on the growth of glioma was studied in vivo. The growth inhibition rate of radix hedysari polysaccharide on U251 cell line was determined by the MTT assay. The cell cycle of U251 was analyzed by flow cytometry. The expression of cytokines in U251 cells and tumor tissues was detected using PCR. The phagocytosis of macrophages in the serum of glioma nude mice was detected by Giemsa staining. TNF-α signaling pathway proteins in the serum of glioma nude mice were detected by ELISA. Results. Radix hedysari polysaccharide inhibited the growth of U251 cells, induced apoptosis in G1 phase by cell cycle arrest, and facilitated apoptosis in glioma mice by regulating cell cycle. Mice injected with radix hedysari polysaccharide showed delayed tumor growth and grew slowly. Radix hedysari polysaccharide enhanced the phagocytosis of macrophages in glioma nude mice. Radix hedysari polysaccharides could inhibit tumor development by regulating the immune function of tumor mice and affecting the TNF-α signaling pathway. Conclusion. Radix hedysari polysaccharide can effectively inhibit the growth of glioma and affect the TNF-α signaling pathway, thus playing an antiglioma role.
      PubDate: Thu, 25 Jul 2019 11:05:06 +000
       
  • The Influence of Additive Manufacturing Processes on the Performance of a
           Periodic Acoustic Metamaterial

    • Abstract: Advancements in 3D print technology now allow the printing of structured acoustic absorbent materials at the appropriate microscopic scale and sample sizes. The repeatability of the fundamental cell unit of these metamaterials provides a pathway for the development of viable macro models to simulate built-up structures based on detailed models of the individual cell units; however, verification of such models on actual manufactured structures presents a challenge. In this paper, a design concept for an acoustic benchmark metamaterial consisting of an interlinked network of resonant chambers is considered. The form chosen is periodic with cubes incorporating spherical internal cavities connected through cylindrical openings on each face of the cube. This design is amenable to both numerical modelling and manufacture through additive techniques whilst yielding interesting acoustic behaviour. The paper reports on the design, manufacture, modelling, and experimental validation of these benchmark structures. The behaviour of the acoustic metamaterial manufactured through three different polymer-based printing technologies is investigated with reference to the numerical models and a metal powder-based print technology. At the scale of this microstructure, it can be seen that deviations in surface roughness and dimensional fidelity have a comparable impact on the experimentally measured values of the absorption coefficient.
      PubDate: Wed, 24 Jul 2019 00:05:33 +000
       
  • Nanoparticles Containing Hyaluronan Acid and Astragalus Polysaccharides
           for Treating Osteoarthritis

    • Abstract: The pathogeny of osteoarthritis (OA) is very complicated and still is one of the difficulties in a treating procedure. Here, we constructed nanoparticles using hyaluronan acid (HA) and astragalus polysaccharides (APS) for OA therapy. We assessed OA biomarkers and IL-1β-induced matrix metalloproteinase (MMP) expressions. Nanoparticles of 100 nm showed high drug loading of 28.6% () and extended drug release of 59% over 1 month. Our results demonstrated that nano treatment significantly improved IL-1β-induced cell viability of chondrocytes. Induction of MMP-9, MMP-13, and TNF-α was alleviated by nanoparticles. Furthermore, nano elevated the expression of osteopontin (OPN) and attenuated inducible nitric oxide synthase (iNOS) protein. Our data indicated the protective role of HA and APS-capsuled nanoparticles in OA treatment.
      PubDate: Sun, 14 Jul 2019 00:05:28 +000
       
  • Lignosulfonates as Fire Retardants in Wood Flour-Based Particleboards

    • Abstract: Wood flour particleboards (WFP), like other wood-based items, require the addition of fire retardants (FRs) to reduce their high flammability. In this work, a waste lignosulfonate (CaLS) from paper mill is used as a low-cost FR to reduce WFP flammability. CaLS is purified by dialysis and the dialysed lignosulfonate (LD) is used, alone or combined with ammonium polyphosphate (APP), as a FR additive in the preparation of urea-formaldehyde WFP. The fire behaviour of the modified WFPs is studied by cone calorimetry. The use of 15 wt.% LD reduces the peak of heat release rate (HRR) and total smoke production by 25%, also increasing char formation. HRR peak is further reduced up to 40%, if APP is introduced in the formulation. This work discloses a viable and cost-effective strategy for improving the fire retardancy performance of WFP by partial replacement of a commercial FR with a fully renewable additive, isolated through a green and cost-effective process.
      PubDate: Thu, 11 Jul 2019 11:05:04 +000
       
  • Controlled Release of Ropivacaine from Single-Armed (1-PCL) and Four-Armed
           PCL (4-PCL) Microspheres

    • Abstract: Sustained release of anesthesia has shown great promise in the treatment of chronic pain in patients. In this research, we used neutralized ropivacaine as an anesthesia and poly(ε-caprolactone) (PCL) with different architectures to systematically study how these architectures affect the release of ropivacaine. After optimizing the parameters of the preparation of microspheres, ropivacaine-loaded 1-PCL microspheres and 4-PCL microspheres were obtained. Fourier Transform infrared spectra (FT-IR) and X-ray diffraction spectra (XRD) confirmed that ropivacaine was encapsulated within the microsphere rather than inserted on the surface of the microsphere. Ropivacaine was found to be buried deeper in the 1-PCL microsphere than in the 4-PCL microsphere. In vitro release assay revealed that small crystalline grains interfered with ropivacaine release in 4-PCL microspheres during the initial release period, but then two kinds of microspheres showed a similar ropivacaine release rate. We basically proved that the architecture of PCL has a negligible effect on ropivacaine release. Cell proliferation test revealed that the release of products from the microspheres resulted in insignificant toxicity towards mammalian cells.
      PubDate: Wed, 03 Jul 2019 00:05:10 +000
       
  • Novel Protein-Repellent and Antibacterial Resins and Cements to Inhibit
           Lesions and Protect Teeth

    • Abstract: Orthodontic treatment is increasingly popular as people worldwide seek esthetics and better quality of life. In orthodontic treatment, complex appliances and retainers are placed in the patients’ mouths for at least one year, which often lead to biofilm plaque accumulation. This in turn increases the caries-inducing bacteria, decreases the pH of the retained plaque on an enamel surface, and causes white spot lesions (WSLs) in enamel. This article reviews the cutting-edge research on a new class of bioactive and therapeutic dental resins, cements, and adhesives that can inhibit biofilms and protect tooth structures. The novel approaches include the use of protein-repellent and anticaries polymeric dental cements containing 2-methacryloyloxyethyl phosphorylcholine (MPC) and dimethylaminododecyl methacrylate (DMAHDM); multifunctional resins that can inhibit enamel demineralization; protein-repellent and self-etching adhesives to greatly reduce oral biofilm growth; and novel polymethyl methacrylate resins to suppress oral biofilms and acid production. These new materials could reduce biofilm attachment, raise local biofilm pH, and facilitate the remineralization to protect the teeth. This novel class of dental resin with dual benefits of antibacterial and protein-repellent capabilities has the potential for a wide range of dental and biomedical applications to inhibit bacterial infection and protect the tissues.
      PubDate: Tue, 02 Jul 2019 11:05:07 +000
       
  • Influence of Natural Fillers on Thermal and Mechanical Properties and
           Surface Morphology of Cellulose Acetate-Based Biocomposites

    • Abstract: In the present study, the influence of adding natural fillers to a cellulose acetate (CA) matrix, in order to develop biocomposites, on the properties of the achieved materials has been investigated. Extracted wood flour, holocellulose, and alpha cellulose were used as appropriate fillers. The results of the thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) of the fillers and biocomposites suggested the importance of the degree of degradation of filler properties, induced by the chemical treatment necessary for the preparation of the fillers, with emphasis on the content of lignin and the degradation of cellulose. Scanning electron microscopy (SEM) and mechanical analysis revealed that the matrix-filler ratio had a major effect on the prepared CA-based biocomposites, since polarity differences between the two major components caused the reduction of attractive forces in the matrix-filler relation, subsequently altering the properties of the developed materials.
      PubDate: Thu, 27 Jun 2019 10:05:22 +000
       
  • Effects of Zinc-Free Processing Aids on Silica-Reinforced Tread Compounds
           for Green Tires

    • Abstract: With the development of “green tires” in the tire industry, the conventional carbon black filler that is used in tread formulations is being replaced with silica. Generally, this requires the addition of a processing aid, containing zinc ion, which acts as a lubricant and dispersing agent. However, because zinc is a heavy metal, zinc-free processing aids (ZFAs) are required to satisfy worldwide environmental concerns. We present herein a series of catalytically synthesized ZFAs and evaluate the effects of replacing zinc ion-containing processing aids (ZCAs) on a silica tread formulation. Interestingly, replacing ZCA with ZFA in a two parts per hundred rubber (phr) by weight formulation improved both its tensile strength and elongation by as much as 31% and 20%, respectively. ZFA-rubber formulations also exhibited a twofold enhancement in fatigue properties over those of ZCA-rubber formulations. Furthermore, pneumatic tires were fabricated from our ZFA-rubber formulation and compared against tires containing ZCAs. The ZFA-rubber composite exhibited improved dry and wet braking and rolling resistance due to enhanced dispersion of silica in the rubber matrix. These results show that rubber composites prepared with ZFAs may be promising in tire engineering applications.
      PubDate: Tue, 25 Jun 2019 10:05:24 +000
       
  • Exploiting the Potential of Moringa oleifera Oil/Polyvinyl Chloride
           Polymeric Bionanocomposite Film Enriched with Silver Nanoparticles for
           Antimicrobial Activity

    • Abstract: The present study focused on the prospect of fabricating a polymeric naturally extracted Moringa oleifera oil bionanocomposite film enriched with silver nanoparticles for antimicrobial activity. In this study, a standard concentration of Moringa oleifera oil (5-10 wt%) was used to fabricate a polymeric bionanocomposite film using polyvinyl chloride (PVC) enriched with silver nanoparticles. The active constituents of the extracted Moringa oleifera oil were verified using gas chromatography-mass spectrometry. Spectroscopic and microscopic techniques, including scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray analysis, were employed to characterize and study the surface morphology of the fabricated bionanocomposite film. The antimicrobial activity of the fabricated bionanocomposite film was investigated using different strains of bacteria and fungus. The results revealed well-oriented and excellently dispersed silver nanoparticles in the PVC-Moringa oleifera oil matrix. The bionanocomposite was able to inhibit the growth of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Salmonella typhi, Pseudomonas aeruginosa, Shigella flexneri, and Candida albicans. The combination of nanoparticles with polymers is opening new routes for engineering fixable composites, which showed antimicrobial properties.
      PubDate: Mon, 17 Jun 2019 10:05:16 +000
       
  • Effect of Porous Chitosan Microspheres Loaded with Platelet-Rich Plasma
           and Bone Marrow-Derived Mesenchymal Stem Cells on Regeneration of Tibia
           Defect

    • Abstract: Objective. Repair of bone defects represents a grave clinical challenge because of the tremendous difficulties in the recovery of bone function and regeneration of bone loss. Therefore, we investigated the effects of platelet-rich plasma-loaded (PRP) porous chitosan microspheres (PCMs) on the differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) and the proliferation and differentiation potential of BMSCs loaded by PCMs in vitro. We also established the model of bone defect repair in rat tibia to further explore the effects of PCMs loaded with PRP and BMSCs on bone regeneration. Methods. MTT assay was used to detect the proliferative ability of BMSCs after hypoxia/reoxygenation (H/R) treatment and the proliferative ability of BMSCs loaded by PCMs; polymerase chain reaction (PCR) was used to detect the expression of alkaline phosphatase (ALP), type I collagen (Col I), and type II collagen (Col II) in BMSCs after hypoxia and in BMSCs induced by PRP-loaded PCMs; PCR was used to detect the expression of Runt-associated transcription factor 2 (Runx2) and osteocalcin (OC) in the newly generated bone tissue; micro-CT scanning was applied to measure the bone mineral density and bone volume of the newly generated bone tissue in rats. Results. BMSCs still have the normal potential of proliferation and differentiation after H/R treatment. PCMs can provide a larger surface for the attachment of BMSCs, facilitating cell proliferation. Loaded by PCMs, PRP can be slowly released, effectively stimulating the differentiation of BMSCs. PCM/PRP/BMSC composites increased the expression levels of Runx2 and OC in the newly generated bone in rat tibia defect and the bone mineral density. Moreover, the composites improved the rate of regenerated bone volume. Conclusion. The application of PCM/PRP/BMSC composites is promising in the repair of tibia defects.
      PubDate: Thu, 13 Jun 2019 07:05:12 +000
       
  • Temperature Driven Transformation in Dextran-Graft-PNIPAM/Embedded Silver
           Nanoparticle Hybrid System

    • Abstract: During the last decade, stimuli-responsible polymers based on poly(N-isopropylacrylamide) having conformational transition in the range of physiological temperature have been discussed as novel drug delivery nanosystems. A star-like copolymer with a dextran core and grafted poly(N-isopropylacrylamide) arms (D-g-PNIPAM) was synthesized, characterized, and used as a matrix for silver sol preparation. The comparative study of the behavior of individual D-g-PNIPAM and the nanohybrid system D-g-PNIPAM/silver nanoparticles has been done in the temperature range near the lower critical solution temperature (LCST). The methods of Dynamic Light Scattering, small angle X-ray scattering, and UV-VIS absorption spectroscopy have been used. The existence of single nanoparticles and aggregated nanoparticles located in a limited polymer macromolecular volume was established. The increase of the temperature leads to slight aggregation of the silver nanoparticles at the LCST transition. Single nanoparticles do not aggregate with the temperature increase. The thermally induced collapse of end-grafted poly(N-isopropylacrylamide) chains above the LCST do not affect significantly the size characteristics of silver nanoparticles incorporated into the polymer matrix.
      PubDate: Wed, 12 Jun 2019 00:05:18 +000
       
  • Investigation of the Effects of Different Hydrophilic and Hydrophobic
           Comonomers on the Volume Phase Transition Temperatures and Thermal
           Properties of N-Isopropylacrylamide-Based Hydrogels

    • Abstract: In this work, a series of thermally responsive terpolymers of N-isopropylacrylamide (NIPA) with three different comonomer contents was synthesized, and their swelling behaviour was studied as a function of composition and temperature. Temperature-sensitive, random cross-linked terpolymers of NIPA were prepared from methyl methacrylate (MMA), N-tert-butylacrylamide (NTBA), and acrylic acid (AA) using a free radical polymerization method. In the synthesis of terpolymer hydrogels, N,N-methylene bisacrylamide (BIS) was used as cross-linkers and ammonium persulfate (APS) as initiator. The NIPA content of the monomer feed varied from 80 to 50 mol %, and other comonomer feed varied from 40 to 5 mol %. The swelling equilibrium of these hydrogels was studied as a function of temperature and hydrophobic and hydrophilic comonomer contents. The swelling properties of the polymers were investigated in pure water at temperatures from 10 to 80°C. All of the synthesized gels were found to be sensitive to temperature. Glass transition temperature analyses and thermal analyses of the synthesized hydrogels were studied. The volume phase transition temperature and the swelling equilibrium () values of NIPA-based hydrogels synthesized in different feed ratios and in varying monomer contents were found in the range of 17–52°C and 14–51 g H2O/g polymer, respectively. The glass temperature () of the NIPA/AA/(MMA or NTBA) hydrogels synthesized with feed ratios of 50/40/10 was found to be 133 or 142°C, respectively. The initial and the end degradation that were determined for hydrogels at high temperatures indicated the quite good thermal stability of hydrogels. When the mass loss of the synthesized hydrogels was 50%, the temperatures were measured between 247 and 258°C.
      PubDate: Mon, 10 Jun 2019 13:05:17 +000
       
  • Thermal Stability of Shear-Induced Precursors and Their Effect on the
           Crystalline Structure of β-Nucleated Isotactic Polypropylene

    • Abstract: The thermal stability and lifetime of shear-induced precursors under various annealing temperatures, as well as the influence of their relaxation on the crystalline modification in β-nucleated isotactic polypropylene (iPP), are investigated using an ARES rheometer. The wide-angle X-ray diffraction results show that the β-crystal content of sheared β-nucleated iPP samples gradually increases with thermal treatments. The relaxation of shear-induced precursors during annealing which caused the decrease of shear nuclei may restrain the counteraction effect between the shear flow and β-nucleation agent as well as result in the increase of β-crystal content. At the early stage of relaxation, the relaxation degree is closely related to the increase of β-crystals, for which the deeper relaxed shear-induced precursors result in the more restoration of β-crystals. However, when the relaxation degree exceeded a certain limitation, where the β-crystals reached the maximum, the relaxation of shear-induced precursors will no longer influence the crystal structure of β-nucleated iPP.
      PubDate: Tue, 04 Jun 2019 13:05:05 +000
       
  • High-Efficiency DNA Extraction Using Poly(4,4-Cyclohexylidene Bisphenol
           Oxalate)-Modified Microcrystalline Cellulose-Magnetite Composite

    • Abstract: In this study, we studied the DNA extraction capability of poly(4,4-cyclohexylidene bisphenol oxalate) following the surface modification and composite formation with that of microcrystalline cellulose (MCC) and magnetic iron oxide nanoparticles (NPs). The physical characterization techniques like scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, energy-dispersive X-ray analysis (EDX), and thermogravimetric analysis (TGA) were employed for the poly(bisphenol Z oxalate)-MCC-magnetite composite during different stages of its formation. The results confirmed the successful modification of the polymer surface. On testing in the presence of three types of binding buffers, a high value of 72.4% (out of 10,000 ng/μL) efficiency with a total yield of DNA at ng and absorbance ratio of A260/A280 (1.980) was observed for the 2 M GuHCl/EtOH binding buffer. These results were compared against the other two buffers of phosphate-buffered saline (PBS) and NaCl. The lowest value of DNA extraction efficiency at 8125 ng/μL of 58.845% with absorbance ratios of A260/A280 (1.818) for PBS was also observed. The study has concluded an enhancement in the DNA extraction efficiency when the polymer is in the composite stage along with cellulose and magnetite particles as compared against the bare polymer.
      PubDate: Tue, 04 Jun 2019 12:05:07 +000
       
  • Piroxicam-Collagen-Based Sponges for Medical Applications

    • Abstract: Depending on the concentration of the drug and/or the method of administration, drugs could be used in various ways. To take full advantage of the drug beneficial properties in oral medical interventions but also in other types of surgery, like plastic surgery, general surgery, or gynecological surgery, the drug concentration as well as the administration method itself will depend on the wound, type of surgery, and severity of the postoperative pain which can be very different. Generally, the local administration methods are recommended. Piroxicam, a nonsteroidal anti-inflammatory drug (NSAID) of the oxicam class, is generally used to relieve the symptoms of pain and inflammation. Starting from the idea of the special benefit of the interference between collagen-based materials and drug beneficial properties, our work was focused on the synthesis and characterization of new collagen-piroxicam materials. These new collagen-based materials present a good water absorption, and the piroxicam release suggests a biphasic drug release profile whereas the obtained values for the release exponent revealed a complex release mechanism including swelling, diffusion, and erosion.
      PubDate: Wed, 29 May 2019 11:05:25 +000
       
  • The Amphoteric Ion Exchange Membrane Based on CS/CMC for Tobacco-Protein
           Adsorption and Separation from Tobacco Extract

    • Abstract: A macroporous amphoteric ion exchange membrane was prepared by blending chitosan (CS) and carboxymethylcellulose (CMC) in aqueous solution, with glutaraldehyde as a crosslinking agent and silica particles as porogens. The good compatibility between CS and CMC was confirmed by attenuated total reflectance Fourier-transform infrared spectroscopy (FTIR-ATR). A scanning electron microscope was used to observe the morphology of CS/CMC blend membranes, in which a three-dimensional opening structure was formed, and no phase separation was discovered. Tobacco extract was used as a separation model to get tobacco protein. And the effects of the pH value, adsorption time, CS/CMC content, initial protein concentration, and CS/CMC composition on tobacco protein adsorption were investigated by coomassie blue staining during the adsorption process. The results showed that the maximum adsorption capacity of 271.78 mg/g can be achieved under the condition of pH 6.15, adsorption time of 8 h, initial protein concentration of 1.52 mg/mL, and CS/CMC weight of 0.05 g with a mass ratio of 80 : 20. Tobacco proteins were successfully separated from tobacco extract by adjusting the pH of the feed and the desorption solutions to change their electrostatic force. It was found that the high desorption capacity and protein desorption efficiency can be achieved at pH 9.40. The blend membranes also demonstrated good reusability after 3 adsorption-desorption cycles.
      PubDate: Tue, 28 May 2019 10:05:54 +000
       
  • The Viscosity Effect of Masticated Natural vs. Synthetic Isoprene Rubber
           on Toughening of Polylactic Acid

    • Abstract: This study investigated the different viscosity effects of natural isoprene rubber (NR) compared to the synthetic one (IR) on toughening of polylactic acid (PLA). Here, 15 wt% rubber was melt blended with PLA in an internal mixer at 180°C and 50 rpm. It was found that the addition of these rubbers led to a significant increase in the tensile toughness and impact strength. These rubbers were masticated at 50°C and at 200 rpm for various mastication times to reduce their molecular weights. A too-long mastication time was found to adversely affect the impact strength and tensile toughness due to the fast agglomeration of rubber particles. At a comparable viscosity, it was remarkable that the impact strength of PLA/NR was higher than that of PLA/IR regardless of the similar chemical structures probably because the presence of nonrubber components including proteins and lipids could enhance the interfacial interaction between NR and the PLA matrix.
      PubDate: Mon, 27 May 2019 16:05:10 +000
       
  • Effect of an Anhydride Excess on the Curing Kinetics and Dynamic
           Mechanical Properties of Synthetic and Biogenic Epoxy Resins

    • Abstract: This work analyzes the effect of the anhydride excess on the nonisothermal curing kinetics and on the final properties of synthetic and biobased epoxy resins. Diglycidyl ether of bisphenol A (DGEBA) and epoxidized soybean oil (ESO) were crosslinked using methyltetrahydrophthalic anhydride (MTHPA) as a curing agent and 1-methylimidazole (1MI) as an initiator. It was shown that the ESO/MTHPA/1MI system reacts slower than the DGEBA/MTHPA/1MI system, giving place to a more significant evaporation of the curing agent during the reaction. As a result, an excess of anhydride improves the final thermal properties of the ESO/MTHPA/1MI network, contrary to the behavior observed for DGEBA/MTHPA/1MI. The knowledge of the kinetics of the curing process and the optimal amount of the curing agent for each system is of critical importance for a more efficient processing of these materials.
      PubDate: Sun, 26 May 2019 13:05:09 +000
       
  • Investigation of the Specific Retention Volume of the Probe Volume and the
           Effects on the Polymer-Probe System by Inverse Gas Chromatography

    • Abstract: In this study, the effects of probe quantities on retention volume and the physical and thermodynamic results of polymer-probe systems were investigated. For this purpose, by using inverse gas chromatographic method. Alcohols and alkanes with different chemical and physical properties were injected as probes on homopolymer (2-cyclohexylidene-1,3-dioxolane-4-yl-methyl methacrylate) (CHMMA). Probe quantities of 0.3, 0.6, and 0.9 μl were selected, and an injection was made at every 10°C between 40 and 150°C. In addition, 3 μl volume probes were tried but reproducible results were not obtained in these volumes and the detector was observed to be out of order after several injections. It has been observed that the specific retention volume of alcohols and alkanes partially increased by increasing the injection amount. A linear relationship was observed between probe quantities and specific retention volume. This linear relationship is apparent from the specific retention volume values, where the probes are independent of the physical and chemical structures. It was observed that the results obtained in all three injections were close to each other and within acceptable limits. The glass transition temperature of the polymer was determined to be a of 60°C. The thermodynamic data calculated for the injection of different amounts of probes were close to each other.
      PubDate: Tue, 21 May 2019 16:05:07 +000
       
  • Preparation and Characterization of Rigid Polyurethane Foams with
           Different Loadings of Lignin-Derived Polycarboxylic Acids

    • Abstract: Lignin was modified by oxidation to prepare lignin-derived polycarboxylic acids (LPCAs). LPCAs can be introduced into rigid polyurethane foams (RPUFs) via 1,4-dioxane. The expansion ratio and compressive strength of RPUFs were observed. When the loading of LPCAs was 0.67 wt% (based on polyol), the compressive strength of RPUF was the highest and was about 59.2% higher than that of the blank RPUF. The reinforcing mechanism of LPCAs was supposed that the interactions between LPCAs and RPUFs increased the strength of the cell walls. When the loading of LPCAs was less than 0.33 wt%, the expansion ratio of RPUFs increased slightly. The water resistance of RPUFs was not affected by LPCAs, suggesting that RPUFs with LPCAs could be used in a humid environment. Besides, the application of the oxidative modification products of lignin was broadened.
      PubDate: Sun, 19 May 2019 00:05:12 +000
       
 
 
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