Biocopolyesters of Poly(butylene succinate) Containing Long-Chain Biobased Glycol Synthesized with Heterogeneous Titanium Dioxide Catalyst

Poly(butylene succinate) (PBS) is a thermoplastic and biodegradable polyester characterized by high rigidity due to its high crystallinity. However, the use of long-chain biobased monomers to produce segmented copolymers is an effective strategy to tailor the properties of PBS, such as increasing flexibility. In this Article, a series of aliphatic biocopolyesters of poly(butylene succinate-dilinoleic succinate) (PBS-DLS) were successfully synthesized via a direct two-step polycondensation method using a semipilot scale reactor for melt polymerization and titanium dioxide/silicon dioxide coprecipitate catalyst (C-94), an alternative catalytic system. The change in catalyst led to a reduced reaction time and eliminated the distillation step required for the typical organometallic titanium catalyst, thus representing an improvement in energy efficiency. In this study, the thermal and mechanical properties were investigated and compared, focusing on the effect of varying the amount of biobased dilinoleic diol in the structure. With increasing amount of long-chain diol, a decrease in molecular weight, density, and melt flow index was observed. The semicrystalline nature of the copolymers was confirmed using differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) methods. Increasing the soft DLS segment content in the copolymer series resulted in an increase in the elastic behavior of the polymers. The broad range of crystallization temperatures and melt flow index values indicates that a polyester library with customizable properties that spans PBS applications has been successfully obtained.