Abstract Microwave-assisted synthesis of the lipase-catalyzed ring opening polymerization of ε-caprolactone (ε-CL) and ω-pentadecanolactone (ω-PDL) monomers was studied. A series of P(CL-co-PDL), with different molar feed ratios, including (ε-CL/ω-PDL) 100/0, 75/25, 50/50, 25/75, and 0/100, were synthesized. The resulting polyesters were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The microwave-assisted polymerization of the monomers reached high conversions (91–95%) within 60 min. FTIR spectra showed the typical absorption bands of these polyesters. A very intense band in the carbonyl region, which was shifted from 1,720 cm−1 for PCL to 1,732 cm−1 for PPDL homopolymer, as well as peaks owing to methylene groups in the 2,990–2,850 cm−1 range. DSC results revealed that all polyester samples were semi-crystalline. Interestingly, the copolymers exhibited only one melting peak (T m), and their T m values linearly increased from 57°C to 95°C as PPDL concentration was increased. Thermal stability of polyesters also depended on PDL content; an increase in PDL concentration increases polymer degradation temperature (T d).

中文翻译：

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ε-己内酯和ω-十五内酯的脂肪酶催化开环共聚的微波辅助合成：热和FTIR表征

摘要 研究了微波辅助合成 ε-己内酯 (ε-CL) 和 ω-十五内酯 (ω-PDL) 单体的脂肪酶催化开环聚合。一系列具有不同摩尔进料比的 P(CL-co-PDL)，包括 (ε-CL/ω-PDL) 100/0、75/25、50/50、25/75 和 0/100，分别为合成的。所得聚酯通过傅里叶变换红外光谱 (FTIR)、差示扫描量热法 (DSC) 和热重分析 (TGA) 进行表征。单体的微波辅助聚合在 60 分钟内达到了高转化率（91-95%）。FTIR 光谱显示了这些聚酯的典型吸收带。羰基区域中的一个非常强的带，从 PCL 的 1,720 cm-1 移动到 PPDL 均聚物的 1,732 cm-1，以及由于亚甲基在 2,990-2,850 cm-1 范围内的峰。DSC 结果显示所有聚酯样品都是半结晶的。有趣的是，共聚物仅表现出一个熔融峰 (T m)，并且随着 PPDL 浓度的增加，它们的 T m 值从 57°C 线性增加到 95°C。聚酯的热稳定性还取决于 PDL 含量；PDL 浓度的增加会增加聚合物降解温度 (T d)。