Random and Multiblock PBS Copolyesters Based on a Rigid Diol Derived from Naturally Occurring Camphor: Influence of Chemical Microstructure on Thermal and Mechanical Properties

Abstract

(1R,3S)-1,2,2-trimethylcyclopentane-1,3-dimethanol (TCDM) is a rigid alicyclic diol prepared by oxidation and subsequent reduction of naturally occurring camphor. To improve the low glass transition temperature (Tg), slow degradation rate, and brittleness of poly(butylene succinate) (PBS), two series of PBS copolyesters based on TCDM were synthesized using two different methods. Random copolymerization (RC) of a mixture of TCDM, 1,4-butanediol (BDO), and 1,4-succinic acid (SA) afforded random PBS copolyesters, while reactive blending (RB) of pure PBS and PTS (homopolyester based on TCDM and SA) afforded PBS copolyesters with blocklike chemical microstructures. For both series, the insertion of TCDM units resulted in elevated thermal stability and higher Tg values compared to those of neat PBS. The RB-prepared copolyesters displayed higher melting points, a higher degree of crystallinity, and higher mechanical properties with respect to those of their random counterparts obtained by RC. The incorporation of TCDM units enhanced the hydrolytic degradation rates for both series, which is more pronounced for the RC-prepared copolyesters. Overall, this work confirmed the effectiveness of the RB technology in preparing high-performance biopolymers such as improving the sustainability of raw materials, achieving high Tg values, and promoting the mechanical strength and biodegradability as well.