Improving the Hydrolysis Rate of the Renewable Poly(hexamethylene sebacate) Through Copolymerization of a Bis(pyrrolidone)-Based Dicarboxylic Acid

Abstract

In this work, we report on the synthesis of a series of polyesters based on 1,6-hexanediol, sebacic acid, and N,N’-dimethylene-bis(pyrrolidone-4-carboxylic acid) (BP-C2), of which the latter is derived from renewable itaconic acid and 1,2-ethanediamine. Copolymers with a varying amount of BP-C2 as dicarboxylic acid are synthesized using a melt-polycondensation reaction with the aim of controlling the hydrolysis rate of the polymers in water or under bioactive conditions. We demonstrate that the introduction of BP-C2 in the polymer backbone does not limit the molecular weight build-up, as polymers with a weight average molecular weight close to 20 kg/mol and higher are obtained. Additionally, as the BP-C2 moiety is excluded from the crystal structure of poly(hexamethylene sebacate), the increase in BP-C2 concentration effectively results in a suppression in both melting temperature and crystallinity of the polymers. Overall, we demonstrate that the BP-C2 moiety enhances the polymer’s affinity to water, effectively improving the water uptake and rate of hydrolysis, both in demineralized water and in the presence of a protease from Bacillus licheniformis.

High‐Performance BioNylons from Itaconic and Amino Acids with Pepsin Degradability

“…[18,19] The enzymatic degradation should induce the pyrrolidone ring-opening to reduce the thermostability. [25,26] As a consequence, the pepsin-degradation may lead to keeping safety in digestive tracts of mammals even when they mistake to swallow the IA-derived polyamide plastics.…”

“…[21,23,24] In particular, symmetrical bis(pyrrolidone)-based dicarboxylic acids prepared from itaconic acid are polymerized and yield amorphous and degradable polymers with low T g values that are susceptible to enzymatic depolymerization. [25,26] However, conventional nonchiral polyamides such as nylon 6, nylon 66, and nylon 11 are not degradable whereas polyamides (nylon 4 and its copolymer nylon-4,4 and -5,4), which were derived from γ-aminobutyric acid (GABA) are biodegradable. [27][28][29] The polyamides from symmetrical monomers were studied, but monomers having head-tail asymmetry such as amino acids should be effective on The use of renewable feedstock for polymers has led to poor thermomechanical properties with high production costs.…”