二苯基甲烷二异氰酸酯-二乙基甲苯二胺聚脲的光谱分析和热分析

SPECTRAL AND THERMAL ANALYSES OF POLYUREA BASED ON MDI AND DETDA

采用广角 X 射线衍射光谱法、傅里叶变换红外光谱法和示差扫描量热法,研究了由等摩尔4,4′-二苯基甲烷二异氰酸酯和3,5-二乙基甲苯二胺在油浴40℃、反应2h 下制备的聚脲的结构。结果表明,聚脲可以形成结晶度为52.9%的微晶,在 FTIR 谱图的脲羰基区存在1691,1678,1657,1642cm^(-1)谱带。在结晶熔点以下对试样进行热处理,聚脲聚集态结构发生了某种不可逆的变化。

The spectral and thermal analyses of the polyurea based on 4,4′-diphenylmethane di- isocyanate(MDI)and 3,5-diethylmethane diamine(DETDA)were carried out by WAXD,FTIR and DSC methods.The WAXD analysis showed that crystallite was formed in the polyurea.Four FTIR bands, 1691,1678,1657 and 1642 cm^(-1),were shown in the carbonyl region of the FTIR spectrum of the polyurea.A nonreversible change of the polyurea structure was observed under thermal treatment near 120℃.The bands and the change were considered to be related to the hydrogen bonding of urea link- ages with different order content.