1,6-六亚甲基二异氰酸酯自聚产物的结构表征

CHARACTERIZATION OF POLYISOCYANURATE MADE FROM HEXAMETHYLENE DIISOCYANATE

用IR与NMR表征了用醋酸钾为催化剂时 1,6 六亚甲基二异氰酸酯 (HDI)自聚产物的结构 .结果表明 ,自聚主产物是三聚体异氰脲酸酯 ,主要含有三聚体异氰脲基、异氰酸根 ,同时含有由杂质带来的微量氨基甲酸酯、脲基甲酸酯基、取代脲基、缩二脲基 .一维核磁谱及二维化学位移相关谱分辨出 7种羰基 ,一种NCO基 ,确定了氮上 8种不同取代结构的分子链连接情况 .通过建立理论模型 ,定量地描述了自聚产物的结构 .

Isocyanurate made from HDI by using potassium acetate as catalyst was synthesized and characterized by IR and NMR (H-1, C-13, H-1-H-1 COSY, C-13-H-1 HMQC, C-13-H-1 HMBC). The peaks at delta3.29 similar to 3.32, delta3.86, delta3.27, delta3.70, delta4.45, delta3.25 and delta3.45 of the H-1-NMR spectrum were attributed to the hydrogen proton on the a carbon atom connected with the nitrogen atom of N=C=O, the hydrogen proton, on the alpha carbon of the HDI trimer, the hydrogen proton on the carbon connected with the nitrogen of urethane, the hydrogen proton on the alpha carbon of biurea, the hydrogen proton on the carbon connected with the oxygen atom of the carbonyl group of ureido-formate, the hydrogen proton connected with biurea,the hydrogen proton connected with substituted urea, the hydrogen proton connected with the urea carbonyl group of ureido-formate, respectively. The peaks at delta121.46, delta148.58, delta153.60, delta153.91, delta154.36, delta155.44, delta155.93, delta165.29 of the C-13-NMR spectra belonged to the double bonded carbon of N=C=O the carbon on the carbonyl group of the HDI trimer,the carbon on carbonyl of urethane, carbon on. the carbonyl of dual-biurea,the carbonyl of the ureido-formate,the carbon of the carbonyl of biurea, the carbon on the carbonyl of substituted urea,, and the carbon on the carbonyl of ureido-formate. The results showed that the main product of HDI self-polymerization was its trimer, isocyanurate. Isocyanurate and isocyanate groups were the main groups in the trimer. Urethane, urethaneurea, urea, biurea groups were also detected in little amount. 1D and 2D NMR could differentiate seven sorts of carbonyl groups and one N=C=O group, and establish the connections, of all carbon and hydrogen-atoms of mixed structures that originated from eight different substitutions. The content of NCO groups was derived from the results of the NMR characterization, it was about 21%. By using the statistical. method, the average molecular weight and functionality of the trimerization product Were calculated as well, they are 624 632 and 3.1 similar to 3.2, respectively. The consistence of the calculated values of isocyanate content, mean functionality and mean molecular weight with the experimental values (20% 3 and 618) demonstrated the correctness of structure characterization.