Abstract. Cassava starch was used as the main chain in the copolymerization of a superabsorbent polymer composite (SAPC) based on acrylic acid and bentonite. The SAPC was synthesized through graft polymerization using nanosized bentonite as reinforcement. The variables in this experiment were: bentonite concentration, acrylic acid to starch weight ratio, concentration of initiator, and cross linker. The product was characterized using FTIR, SEM and TGA-DSC. The results show that the polymerization reactions involved processes of incorporating starch chains as polymer backbone and grafting acrylic acid monomers onto it. The use of cassava starch in the polymerisation produced a very short reaction time (10-15 minutes), which led to SAPC production with higher efficiency and lower cost. Bentonite interacts with monomers via hydrogen and weak bonding, thus improving the thermal properties of the product. The maximum absorbance capacity obtained was at an acrylic acid to starch weight ratio of 5 and a concentration of initiator, cross linker and bentonite of 0.5, 0.05 and 2 weight percent, respectively. The product is suitable for agricultural and medical applications as well as common superabsorbent polymer applications.
We describe a new approach for obtaining high-performance anion exchange membranes by using a thermally convertible precursor. A new insoluble all-aromatic polymer containing anthracene units and benzyl trimethyl ammonium was successfully prepared from a highly soluble precursor polymer. The resulting polymer shows excellent chemical durability and conductivity.
This research describes morphological aspect of BC-PVA nanocomposite asscaffold for bone tissue that was synthesized by adding PVA to Gluconacetobacterxylinus fermentation medium. PVA concentrationswere varied as 0,3,6,9, and 12 % (w/v) of the medium. The culture was agitated with magnetic stirrer for 28 days. Freeze drying was then conducted to obtain dry BC/PVA nanocomposite. Some nanocomposite samples subjected to sonication treatments. The morphology of BC-PVA nanocomposite was examined by Scanning Electron Microscope (SEM) whileits surface area and pore characteristic were determined by nitrogen adsorption of BJH method (BET device). SEM images showed the smallest fiber diameter of approximately 35 nm andnanocomposite surface that was smoother with higher PVA content in the fermentation medium. The sonicationtreatmentcould enhance nanocomposite surface area from 17,2 m2/g to 72,7 m2/g for pure BC sample and from 9,9 m2/g to 14,3 m2/g for 12% PVA sample. BC/PVA nanocompisite had smaller pore diameter than pure BC and its size increased with more PVA content in the fermentation medium.PVA could modify BC morphology bymakinga hindrance on cellulose nanofiber sothat fiber agglomeration could be avoided andthe sonicationtreatmentshowedto enhance this phenomena.
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