Morphology, Mechanical Properties, and Biodegradability of Modified Thermoplastic Starch/PETG Blends with In Situ Generated Graft Copolymers

This paper reports on synthesis of modified thermoplastic starch (MTPS) and glycol-modified polyethylene terephthalate (PETG) blends in a twin-screw extruder. Scanning electron microscopy (SEM) images showed uniform, microdispersion MTPS PETG matrix, confirming compatibilization the blend by graft copolymers generated situ during reactive extrusion process. Incorporating 30% wt. gives biobased carbon content 22.8%, resulting reduced footprint removal 0.5 kg CO2 from environment/kg resin relative to unmodified PETG. with 80% glycerol grafted onto was prepared A total 33% added backbone as determined soxhlet extraction dichloromethane (DCM). The grafting confirmed presence peak TGA analysis residue appearance carbonyl FTIR spectra after Soxhlet extraction. synthesized MTPS–PETG had lower but acceptable mechanical properties. Even 15% reduction tensile stress 40% strain impact strength obtained adding MTPS, this still good properties can be used many applications requiring balance cost, properties, content. Aqueous biodegradability studies using ISO 14852 that component biodegraded rapidly within 80 days, whereas remained it even 150 days. Thus, study categorically proves addition does not improve nonbiodegradable polymers.