Effect of Potassium Dichromate on Properties and Biodegradation of Gum Arabic Based Bioplastic Membranes

摘要

Gum Arabic (GA) collected from Acacia senegal trees was used with polyvinyl alcohol (PVA) to prepare of a series of biodegradable membranes doped and non-doped with potassium dichromate (K2Cr2O7). Adding the K2Cr2O7 to the GA/PVA blends slightly decreased their crystallinity index (CI) by about 2 %. Increasing the PVA concentration in the chromated GA/PVA blends was responsible for increasing the CI. Adding the K2Cr2O7 to the pure GA solution modified its differential thermal behavior whereby the exothermic reactions occurred between 321°C and 433°C were disappeared. The K2Cr2O7 increased the heat change drastically for all the bioplastic blends with the highest increase for the pure GA. Adding K2Cr2O7 to the pure PVA increased the nanometric particle size (NPS) significantly. Increasing the PVA concentration in a blend had a greater effect than did the K2Cr2O7 on the NPS. The buried bioplastic membranes in the control soil had different count and species of microbial communities. The numbers of bacteria and fungi in the initial soil sample were lower than those for chromated GA membranes and were greater than those for the chromated PVA. All bacterial and fungi species had growth ability and are expected to be detoxification tools of chromium ion-doped blends of GA and PVA leading to a green environment.