回收聚碳酸酯製備環狀胺基甲酸酯之研究與應用

Abstract

本研究以回收聚碳酸酯 (Polycarbonate, PC)為原料，利用不同碳鏈長度之醇胺進行PC胺解，製成含胺基甲酸酯官能基之中間體，由於分子結構的設計，此中間體透過裂解能夠依據所使用的醇胺之碳鏈長度，成功製備五元、六元及七元環狀胺基甲酸酯。此製程相較於傳統備環狀胺基甲酸酯之方法，有無須添加觸媒、步驟較為簡單之優勢。由於此製程為兩步法，本研究亦使用了傅立葉轉換紅外光譜儀(Fourier Transform Infrared Spectroscopy, FT-IR)，搭配熱力學數據及核磁共振(Nuclear Magnetic Resonance Spectrometer, NMR) 探討兩製程步驟之化學反應機制，結果顯示，環化反應與分子內作用力及環狀胺基甲酸酯之穩定性有關。 以開環聚合製備氨酯(Polyurethane, PU)為非光氣法製備聚氨酯的方法之一，本研究所製備之環狀胺基甲酸酯經由陽離子開環聚合製備出線性 PU，再使用NMR、熱重分析儀 (Thermogravimetric Analysis, TGA)及微差掃描熱分析(Differential Scanning Calorimetry, DSC)證實此線性PU與文獻之化學結構、熱性質相符，顯示本論文成功使用環狀胺基甲酸酯製備非光氣法線性聚胺酯 。

Chemical recycling of poly(bisphenol-A carbonate) (PC) into cyclic urethanes was attempted by aminolysis, i.e. amine carbonylation reaction, followed by pyrolysis. By using amino alcohols with different chain lengths as aminolysis agent, the interim prepolymers with carbamate functional groups were developed. Based on the molecular design, the prepolymers were then decomposed into five-membered, six-membered or seven-membered cyclic urethanes dependent on the chain length of aminolysis agent after pyrolysis. This process provided a rather simple and eco-friendly way to synthesize cyclic urethanes in the absence of catalyst. The mechanism of the two-step process was also discussed based on the results of Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectrometer (NMR) and thermodynamics data. These results confirm that the cyclization reaction was influenced by intramolecular interactions and the stability of cyclic urethane. Linear polyurethanes (PU) were also prepared via cationic ring-opening polymerization of cyclic urethanes, which is a non-phosgene route to polyurethanes. The structure of the polyurethane was confirmed by NMR, and thermal properties were analyzed by thermogravimetric analysis and differential scanning calorimetry. The results were comparable with those in the literature.