Bio plastic from tannery wastes

Abstract

newline The leather industry is one of the important sectors contributing to several economic and social benefits. Leather solid waste, emerging out of the tanneries, has been a menace ever since waste generation started polluting the environment. Different kinds of waste such as raw trimmings, fleshing, hair waste, chrome shaving, buffing dust, and finished scraps are discarded from the tanneries while transforming the hide/skin into leather. However, these solid wastes are either dumped or recycled as low-value products like adhesive, protein filler, and poultry feed in the recent past. Untanned wastes like rawhide/skin trimmings contain proteins such as collagen and keratin which can be recovered and reutilised for making bioplastics. This thesis work targets in demonstration of utilising protein and lipid from untanned wastes of leather processing. In order to fabricate bioplastics, an effective strategy of blending the protein extracted from waste, along with modifiers, reinforcement and crosslinkers, has been attempted. Trimming protein hydrolysate with nitrogen content varying between 16.39% and 17.16% has been extracted using the hydrothermal hydrolysis technique. The extracted trimming hydrolysate was blended with polyvinyl alcohol and citric acid as a non-toxic crosslinker. The citric acid used in the bio-plastic preparation acted as a flexible plasticiser. The prepared bioplastic has been demonstrated as a prototype for the fabrication of a flexible organic printed circuit board substrate.