PET/PHB(40/60)共聚反应和链结构

AN INITIAL STUDY ON COPOLYMERIZATION MECHANISM AND CHAIN STRUTURE CHANGE OF PET/PHB(40/60)

本文通过溶解性试验、富里埃红外光谱(FT-IR)、热台偏光显微镜、差示扫描量热仪(DSC)、高分辨核磁共振氢谱(′H—NMR)等方法,对 PET/PHB(40/60)共聚合反应历程,反应过程中嵌段性的形成,以及链结构的变化情况进行了研究。结果表明:共聚合反应初期,同时存在着 PET 的酸性裂介,PHB 的均聚,以及 PET 和 PHB 链段之间的缩聚。随共聚合反应的进行,均聚反应减慢,反应初期所形成的 PHB 刚性链段重新打开参加酯交换反应,共聚酯序列结构由嵌段性逐渐向无规性靠近。

In this paper,the copolymerization mechanism,the formation of block structure at thereaction and the chain structure change of PET/PHB(40/60) were studied by means ofSolubility test,Fourier Transform Infrared Spectrum (FT-IR),Polarizing Microscope,Differential Scanning Calorimetry(DSC) and high resolution Nuclear Magnetic Resonance(H-NMR).The results showed that there existed the acidolysis of PET and thehomopolymerization of PHB together with the copolymerization between segments of PETand PHB at the initial stage of copolymerization reaction.With the development ofcopolymerization reaction,the homopolymerization reaction was reduced,the PHB rigidchain formed at the initial stage of reaction was opened,being able to take part in the esterexchange reaction,and the block property of copolyester sequence structure gradually ap-proached a random one.