Synthesis, Modification, and Characterization of l-Lactide/2,2-[2-Pentene-1,5-diyl]trimethylene Carbonate Copolymers

Abstract

This paper explores the copolymerization of L-lactide (L-LA) with 2,2-[2-pentene-1,5-diyl]-trimethylene carbonate ( c HTC). Since c HTC has a cyclohexene group, this provided a route for preparing poly(lactic acid), (PLA), based chains decorated with controlled quantities of CdC substituents. Ringopening copolymerizations of L-LA with c HTC were successfully conducted in bulk by using AlR3-H2O (R ) ethyl, isobutyl), Al(O i Pr)3, ZnEt2-H2O and Sn(Oct)2 as catalysts. Comparison of these copolymerizations showed that the Sn(Oct)2 catalyst system gave copolymers of relatively higher molecular weight. Increasing the reaction time of Sn(Oct)2 catalyzed copolymerizations from 6 to 24 h resulted in higher copolymer c HTC content and yield but lower copolymer molecular weight. Variation of the comonomer feed ratio was useful in regulating the content of cyclohexene pendant groups in the copolymer. However, regardless of the catalyst used, the mole percent of c HTC incorporated into the copolymer was lower than that used in the monomer feed. Determination of the comonomer reactivity ratios for Sn(Oct)2 catalyzed copolymerizations gave values of 8.8 and 0.52 for L-LA and c HTC, respectively. All gel permeation chromatography (GPC) traces showed unimodal molecular weight distributions. Determination by 13 C-NMR of the copolymer sequence fractions HLL, LLL, LLH, HLH, HL, and LH (H ) c HTC units, L ) L-lactyl units) showed that they were close to those calculated by assuming a Bernoulli statistical propagation. On the basis of these results and the effects of reaction conditions on the copolymer sequence distribution, a mechanism which involves insertion of c HTC into the polymer chain was proposed. Studies by differential scanning calorimetry (DSC) showed that c HTC units in the copolymers disrupted ordering of the L-PLA crystalline phase. Furthermore, the glass transition temperatures (Tg) ranged from 60 (L-PLA) to 33°C (P( c HTC)). Conversion of CdC to epoxy side groups was successfully carried out by using 3-(chloroperoxy)benzoic acid at room temperature with only small decreases in copolymer molecular weight.

Microstructure analysis and thermal property of copolymers made of glycolide and ϵ‐caprolactone by stannous octoate

“…Also, an increase in the reaction temperature resulted in the formation of copolymers with an increased CL content. Interestingly, the same trend of copolymerization versus reaction temperature was reported for 2,2‐dimethyltrimethylene carbonate/ L ‐lactide and 2,2‐[2‐pentene‐1,5‐diyl]trimethylene carbonate/ L ‐lactide copolymerizations catalyzed by ZnEt 2 and Sn(Oct) 2 19, 20…”

Functional biodegradable polymers via ring-opening polymerization of monomers without protective groups

“…They suggested further hydrolysis to diols, reaction with alcohols or amines or initiation of ring-opening polymerization. 307 5.1.5 Other polycarbonates. Venkataraman et al prepared polycarbonates from N-substituted functional eight-membered cyclic carbonates.…”

Alternating Copolymerization of Carbon Dioxide and Cyclohexene Oxide and Their Terpolymerization with Lactide Catalyzed by Zinc Complexes of N,N Ligands

“…Previously, polycarbonate-co-polylactide polymers had only been made by ring opening polymerization of cyclic carbonates and lactide, which bears the drawback of a tedious cyclic carbonate monomer preparation. [39,40] For comparison of catalytic activities some experiments with a literature-known BDI zinc complex (Scheme 4) were carried out under the same conditions.…”