Spectroscopic Investigation of the Polymorphism and Side Group Location of Ethylene Copolymers
Spectroscopic Investigation of the Polymorphism and Side Group Location of Ethylene Copolymers
复制标题
乙烯共聚物多晶型和侧基位置的光谱研究
作者：
Zhiqiang Su;Ying Zhao;Yizhuang Xu;Xiuqin Zhang;Shan;Dujing Wang;Jinguang Wu;C. Han;Duan
用高分辨低温傅里叶变换红外光谱和核磁共振光谱研究了一系列乙烯-乙酸乙烯酯共聚物(−-EVA)及其水解物(EVOH)的晶型和侧基位置。实验结果表明，FTIR光谱可以为侧基进入乙烯链段的晶格提供直接证据。通过对特定红外光谱谱带变化的表征，证明EVOH的羟基进入晶格，而EVA的侧基主要存在于无定形区域。研究了这两个系列乙烯共聚物的晶型和晶相转变。结果表明，所有的EVOH共聚物都只有一个正交晶相。而对于EVA共聚物，除了出现正交晶型结晶相外，还发现了相对稳定的单斜晶相。
The polymorphism and side group location of a series of ethylene−vinyl acetate copolymers (EVA) and their hydrolytic products (EVOH) have been investigated by high-resolution cryogenic Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. The experimental results indicated that FTIR spectra can provide direct evidence for side groups entering the crystal lattice of ethylene segments. Through the characterization of the specific IR band variation, it was proved that the hydroxyl group of EVOH enters the crystal lattice, while the side groups of EVA exist predominantly in the amorphous region. The polymorphism and the crystalline phase transformation were investigated for the two series of ethylene copolymers. It was proved that there is only an orthorhombic crystalline phase for all the EVOH copolymers. For EVA copolymers, however, besides the occurrence of a normal orthorhombic crystalline phase, a monoclinic crystalline phase was also detected for the samples with a relativ...