基于二维红外光谱的聚氨酯微相分离研究

Study on the Micro Phase Separation of Polyurethane by 2D-IR Spectroscopy

以聚醚二元醇(PPG)为软段,通过控制异佛尔酮二异氰酸酯(IPDI)比例,合成了不同软硬段比例的聚氨酯。采用X射线衍射仪(XRD)研究了聚氨酯微晶区的结晶度;采用傅里叶红外光谱仪(FT-IR)、二维红外光谱(2D-IR)分析了聚氨酯NH基峰和C O峰处的氢键作用;并对聚氨酯进行了邵氏硬度实验。结果表明:随着硬段含量从33%增至67%后,硬段微晶区结晶度从0.49%增至8.95%,硬段区氢键作用增长明显;聚氨酯硬段形成的氢键作用主要有软硬段间的无序相氢键作用和硬段之间的有序相氢键作用;在C O峰的2D-IR异步光谱中,随着硬段含量增加,有序相氢键作用增强,有利于先形成硬段微晶区,再在软硬段界面处形成无序相氢键;随着硬段含量的增加,PU胶膜中硬段聚集微区增多,胶膜硬度增大。

In this study,polyether diol(PPG)was used as a soft segment and the ratio of isophorone diisocyanate(IPDI)was controlled to synthesize the polyurethane with different soft and hard segments.The crystallinity of polyurethane microcrystalline zone was studied by XRD.FT-IR and 2D-IR were used to analyze the hydrogen bond interaction at NH and C O base peak of polyurethane.The results showed that it was found that the crystallinity of hard segment increased from 0.49%to 8.95%,the hard segment content grew from 33%to 67%and the hydrogen bond interaction in hard segment increased significantly.The hydrogen bonding between hard segments of polyurethane mainly included the disordered phase hydrogen bonding,and the ordered phase hydrogen bonding mainly existed between the soft and hard segments;in the 2D-IR asynchronous spectrum of C O peak,with an increase of hard segment content,the hydrogen bonding between ordered phase was enhanced which was beneficial to the formation of hard segment microcrystalline region,and then the disordered phase hydrogen bonds were formed at the interface of soft segments and hard segments.At the same time,shore hardness test also showed that with the an increase of hard segment content,the aggregation micro area of hard segment in PU film increased and the hardness of PU film increased significantly.