Study of starch, sugar blending effect on the biodegradability of (PVA) for packaging applications

Abstract

PVA, Starch/PVA, and Starch/PVA/sugar samplesof different concentrations (10, 20, 30 and 40 % wt/wt) were prepared by casting method. DSC analysis was carried; the results showed only one glass transition temperature (Tg) for the samples involved, which suggest that starch/PVA and starch/PVA/sugar blends are miscible. The miscibility is attributed to the hydrogen bonds between PVA and starch. This is in a good agreement with (FTIR) results. Tg and Tm decrease with starch and sugar content compared with that for (PVA). Systematic decrease in ultimate strength, due to starch and sugar ratio increase, is attributed to (PVA), which has more hydroxyl groups that made its ultimate strength higher than that for starch/PVA, and starch/PVA/sugar blends. It is observed from water uptake tests that the solubility time decreases with starch ratio; it is attributed to decrease in hydroxyl groups caused by PVA ratio decrease. The inter- and inter-molecular bonds of the hydroxyl groups enhanced the solubility process of the starch/PVA blends in water. The water immersion causes hydrogen bonds (inter and intermolecular bonds) to decompose, that increases the film solubility. Water absorption and capacity of degradability are most important in biodegradable materials. The results suggest the samples that have undergone investigation, can be used for shopping, and food packaging. The study of soil burial for the sample at (3cm) depth, and at (13cm) depth has exhibited weight loss increase with soil burial time. The biodegradability rapidly increases at the first (6-7) weeks; it is found that the weight loss at (3cm) depth is greater than that at (13cm) that was attributed to the differences in the availability of oxygen ratio. It is found that PVA undergoes lowest weight loss, the weight loss changes with starch, and sugar content. In dry soil, the weight loss is lower. The results proved that the biodegradation decreases with soil burial time after seven weeks of burial. It is concluded that the samples involved are biodegradable material that can be used for packaging applications and biologically friendly synthetic polymer blends to solve the solid waste accumulation problem.