Glycerol: Its properties, polymer synthesis, and applications in starch based films

Glycerol is the major by-product of the biodiesel production line. Every cycle of processing, yields ~10% (w/w) of waste glycerol, and therefore, creates a glut in the glycerol market. The underutilized glycerol has undoubtedly increased the environmental liability. There are plenty of research focusing on discovering the effective glycerol utilization to produce value-added chemical commodity to ensure sustainable consumption and production patterns. This paper portrays the existing connection between glycerol and the polymer industry, particularly as a feedstock for polymer synthesis and its role as a plasticizer in the starch polymer. Glycerol is a potential bio-based material to afford prominent biocompatible yet biodegradable polymers for a variety of applications through direct polymerization, fermentation, and chemical conversion. Besides, glycerol plays a critical role in the food packaging industry to perform a plasticizing effect; it improves the ductility of the bioderived packaging. The native unplasticized starch film is too brittle for handling, while the glycerol-plasticized starch film has adequate flexibility and processability, but with compromised water and gaseous barrier properties. Nevertheless, more established works should be published to exploit the use of this versatile base chemical in diverse fields to good advantages, yet reducing the adverse environmental impact.