Bio-Based and Biodegradable Aliphatic Polyesters Modified by a Continuous Alcoholysis Reaction

Abstract

A novel approach was developed to chemically tailor biodegradable aliphatic polyesters such as polylactic acid (PLA) and polybutylene succinate (PBS) for targeted applications. The reactive extrusion process utilized a catalyzed alcoholysis reaction to controllably cut the aliphatic polyester polymer chains to the desired lengths. During this continuous reaction, aliphatic polyesters reacted with a solution of a diol or functionalized alcohol and a catalyst in melt phase, resulting in modified aliphatic polyesters with hydroxyalkyl chain ends or other functional chain ends useful for further reactions or modifications. Titanium propoxide and dibutyltin diacetate were used as catalysts for alcoholysis reactions of PLA and PBS respectively. It was found that by selectively controlling the alcoholysis conditions, the molecular weights and melt rheology of modified aliphatic polyester were modified to make them suitable for meltblown nonwoven processing. Meltblown nonwovens were successfully spun from both modified PLA and modified PBS, fiber-to-fiber bonding and excellent mechanical properties were achieved from the modified bio-based and biodegradable meltblown nonwoven.