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Journal-of-Polymer-Science websmall

Formulation, Characterization, Study of Swelling Kinetics and Network Parameters of Poly (MA-co-VA-co-AA) Terpolymeric Hydrogels with Various Concentrations of Acrylic Acid
Pages 142-152
Rubab Zohra, Muhammad Aslam Malana and Zafar Iqbal

DOI: http://dx.doi.org/10.6000/1929-5995.2013.02.03.1

Published: 30 September 2013

 


Abstract: The ter-polymeric hydrogels of vinylacetate (VA), methacrylate (MA) and acrylicacid (AA) were prepared using ethyleneglycoldimethacrylate (EGDMA) as a cross linker and benzoylperoxide (BPO) as an initiator. The effect of acrylic acid concentration on various swelling parameters was studied at different pHs (1.0, 4.0, 5.5, 7.4 and 8.0). A promising relationship was found to exist between media penetration velocity and equilibrium media content of hydrogels at all pH values for various concentration of acrylic acid. The fastest dynamic swelling was observed for the highest concentration of acrylic acid (40 mol % of AA) at pH 8.0. In the kinetic study, during the first hours, a first order kinetics (Fick Model) was observed at pH higher than the value of pKa (4.75) of acrylic acid, the hydrogels exhibiting non-Fickian diffusion mechanism. Whereas, for the acidic media pH, a second order kinetics was observed (Schott Model). Network parameters strongly support the swelling out comes. The relaxations of the ter-polymeric chain were observed after swelling at pH 8.0 via SEM pictures. Thermo gravimetric analysis and differential scanning calorimetric analysis also agree with the above conclusions. Well controlled swelling behavior, network properties, SEM out comings and thermo-gravimetric analysis support the idea to use these hydrogels for targeted drug delivery in the colon part of the digestive tract.

Keywords: Hydrogels, acrylic acid, swelling, radical polymerization, ter-polymer.
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Journal-of-Polymer-Science websmall

Can Bio-Based Thermoset Polymers Replace Petrochemical Based Counterparts?
Pages 153-154
Kayode Feyisetan Adekunle

DOI: http://dx.doi.org/10.6000/1929-5995.2013.02.03.2

Published: 30 September 2013

 


Abstract: Specific answers are required for purpose of better communication with many researchers, manufacturers, and users of polymer worldwide. This paper posted so many questions about the research activities on bio-based/ renewable thermoset polymers as against petrochemical based thermoset polymers. Quite a few answers were given but the remaining unanswered questions will surely be required in order to better understand the results achieved in this research area.

Keywords: Renewable, cost-effective, synthesis, environmentally friendly.
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Journal-of-Polymer-Science websmall

Modification and Characterization of Biodegradable Chitosan/ Starch-Based Films with Monomer 1,4-Butanediol Diacrylate (BDDA) by Gamma Radiation
Pages 155-167
Nousin Akter, Suvanker Saha, Farah M.J. Hossain, Fahad B. Quader, Poonam Alamgir and Ruhul A. Khan

DOI: http://dx.doi.org/10.6000/1929-5995.2013.02.03.3

Published: 30 September 2013

 


Abstract: Chitosan reinforced starch-based biodegradable films were prepared by solution casting. Tensile strength (TS), tensile modulus (TM), elongation at break (%), and water vapor permeability (WVP) of the 50% chitosan containing starch-based films were found to be 47 MPa, 550 MPa, 16%, and 2.45 g·mm/m2·day·kPa, respectively.Monomer 1,4 butanediol diacrylate (BDDA) was added (0.25-1% by wt) to the starch/chitosan (50:50) based film formulation. Then, films were cast and gamma irradiated from a radiation dose varied from 1 kGy to 25 kGy. Then mechanical and barrier properties were evaluated. The highest TS (80 MPa) and TM (880 MPa) of the films were found by using 0.5% monomer at 5 kGy dose. The WVP of the films were found to be 1.50 g·mm/m2·day·kPa which is 38.77% lower than control starch/chitosan-based films. Molecular interactions due to incorporation of BDDA were supported by Fourier transform infra red (FTIR) spectroscopy. The water uptake of the films pointed out better hydrophobic character due to incorporation of BDDA in starch/chitosan-based films. Surface morphologies of BDDA treated films were examined by scanning electron microscope (SEM) and suggested better morphologies due to BDDA treatment with starch/chitosan-based biodegradable films.

Keywords: Starch, chitosan, biopolymer, monomer, biodegradable, gamma radiation.
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Journal-of-Polymer-Science websmall

Three-Dimensional Simulation of the Shrinkage Behavior of Injection-Molded Poly Lactic Acid (PLA): Effects of Temperature, Shear Rate and Part Thickness
Pages 168-173
Wenhe Guo, Bin Yang, Ru Xia, Lifen Su, Jibin Miao, Jiasheng Qian, Peng Chen, Xuekang Yu, Qianlei Zhang and Shuangquan Deng

DOI: http://dx.doi.org/10.6000/1929-5995.2013.02.03.4

Published: 30 September 2013

 


Abstract: The effects of injection temperature, shear and part thickness on the linear shrinkage of injection-molded poly (lactic acid) (PLA) were intensively analyzed using the Autodesk Moldflow software. The obtained results showed that both melt temperature and shear rate had obvious effects on the linear shrinkage of PLA, i.e., the linear shrinkage of PLA increases significantly with the increase of melt temperature and shear rate. In addition, the shrinkage of high-crystallinity PLA was remarkably larger than that of low-crystallinity PLA, and thin-walled parts was larger than thick-walled ones in shrinkage..

Keywords: 3D simulation, poly (lactic acid), temperature, shear rate, thickness, shrinkage.
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