Process optimization & reactive extrusion of high-molecular weight Poly(butylene-adipate-co-terephthalate) (PBAT) polymer for film blowing application

Abstract

The present study demonstrates a novel approach of the process optimization for the synthesis of Poly(butylene-adipate-co-terephthalate) polymer, and its exclusive reactive extrusion for the film blowing application. The polymers have been synthesized under different processing conditions in order to determine the effect of different variables on the kinetics and optimize the system to obtain biopolymers. The catalytic chemistry of tetra-isopropyl titanate (TIPT) and zinc acetate in the optimal dosage resulted in the development of very high molecular weight PBAT, which is very essential for a polymer to have superior mechanical properties. The polymers were characterized using gel permeation chromatography (GPC), FT-IR, and calorimetry (DSC) analysis to investigate their properties. Furthermore, the polymer compounding was conducted using a unique reactive extrusion process which resulted in the compound with physiochemical property retention at the reduced polymer dosage level. This novel extrusion process reduced the polymer consumption in the compounding by up to 25% with intact properties. Mechanical and thermal properties were enhanced using metal complex-based inorganic coupling agents and fluoropolymers during the process. In the blowing, a flexible and thin film of uniform thickness was obtained in the continual run on the machine. The films were tested for mechanical properties which were at par with commercially available bags. With the ever-increasing demand for environmental-friendly products in plastics & polymers and stricter regulations against the use against conventional plastics, these polymer-based bio-films can be extensively used in the packaging and plastic bag applications due to their biodegradability and the superior strength in terms of mechanical properties which are comparable to the one exhibited by conventional polyethylene bags.