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

Abstract

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.

Effect of enzymatic versus titanium dioxide/silicon dioxide catalyst on crystal structure of ‘green’ poly[(butylene succinate)‐co‐(dilinoleic succinate)] copolymers

“…This analysis confirmed the formation of the desired chemical structure of PBS‐DLS 70:30_E and PBS‐DLS 70:30_M copolyesters and the successful incorporation of DLA‐OH sequences between DS units, which resulted in the appearance of signals (e), (h), (i), (j) and (k) and signals related to the carbons of DLA‐OH end‐groups. These chemical shifts are not visible on the 13 C NMR spectra of neat PBS sample shown elsewhere 10, 25 …”

“…No significant differences can be observed between PBS‐DLS 70:30_E and PBS‐DLS 70:30_M samples. The incorporation of DLS segments resulted in the appearance of signals (f), (g), (i), (j), (k) and (l) and shoulder signal (e) which are not visible in the 1 H NMR spectra of neat PBS sample presented elsewhere 10, 25 …”

“…The signal located at ⊐ 13 13 C NMR spectra of neat PBS sample shown elsewhere. 10,25 Based on the 1 H NMR spectra, the degree of polycondensation (DP h ) of the hard segments in PBS-DLS 70:30 copolyesters and M n were calculated (Appendix S1).…”

“…We followed a procedure similar to that reported in our previous work to prepare PBS-DLS with 70:30 wt% ratio of hard to soft segments using a titanium-based catalyst, and abbreviated as PBS-DLS 70:30_M. 25 Briefly, two-stage polymerization was performed in which BD, SA (molar ratio of BD to SA of 1.1:1) and a first aliquot of C-94 catalyst (0.06 g per 100 g of SA) were added into a reactor and copolymerized at 180°C, through an esterification reaction. This reaction was run until 95% of theoretical amount of water was separated from reaction mixture (1 h).…”

Architectured helically coiled scaffolds from elastomeric poly(butylene succinate) (PBS) copolyester via wet electrospinning

“…The details of the two-step synthesis and copolymer characterization have been reported in our previous work. 42 Briefly, we charged into the reactor 3.39 mol of SA and 3.73 mol of BD (along with 0.06 g of C-94 catalyst per 100 g of SA) in the esterification stage (1 st step), which was carried out at 180 °C, until 95% of the theoretical amount of water by-product was collected. Next, DLA-OH (0.35 mol), along with a 2 nd aliquot of C-94 catalyst, was added to the reaction mixture, the temperature was increased to 250 °C at an approximated rate of 1.5 °C/min, and the pressure was decreased to 0.2-0.4 hPa in order to start the polycondensation stage (2 nd step).…”