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通过二苯基甲烷-4,4′-二异氰酸酯(MDI)改性钠基蒙脱土(Na-MMT),使Na-MMT呈纳米级剥离态分散,制得MDI改性Na-MMT(M-MMT)。将M-MMT加入至铸型尼龙6体系中原位聚合成型,以解决有机蒙脱土在铸型尼龙6体系中热降解的问题,提高复合材料的耐热性。利用FITR、GC-MS、XRD和TEM研究了改性机理和Na-MMT的分散情况。通过TG、维卡软化、热变形温度测试、力学性能测试和SEM观察,研究了M-MMT/铸型尼龙6复合材料的耐热性、力学性能和微观形貌。结果表明:MDI能与Na-MMT层间的羟基以及水反应使M-MMT呈剥离态分散。虽然在铸型尼龙6体系引发剂定量的情况下,MDI消耗体系引发剂,引起M-MMT/铸型尼龙6复合材料分子量的下降,导致各项力学性能有所下降,但M-MMT的纳米级效应使复合材料的耐热性得到提高,维卡软化点提高至224℃,在1.82 MPa负荷条件下,热变形温度提高至96℃。
The Na-MMT modified by Na-MMT by diphenylmethane-4,4’-diisocyanate (MDI) -MMT). The M-MMT is added to the casting nylon 6 system for in-situ polymerization to solve the problem of the thermal degradation of the organic montmorillonite in the casting nylon 6 system and to improve the heat resistance of the composite. The modification mechanism and dispersion of Na-MMT were studied by FITR, GC-MS, XRD and TEM. The heat resistance, mechanical properties and microstructure of M-MMT / cast nylon 6 composites were investigated by TG, Vicat softening, heat distortion temperature test, mechanical properties test and SEM observation. The results show that the MDI can react with the hydroxyl groups of Na-MMT layer and water to disperse the M-MMT in a stripped state. Although MDI consumes the initiator of the system under the condition of the amount of the initiator of the molding nylon 6 system, the molecular weight of the M-MMT / cast nylon 6 composite decreases, resulting in the decrease of various mechanical properties. However, The effect of grade improves the heat resistance of composites, the Vicat softening point increases to 224 ℃, and the heat distortion temperature increases to 96 ℃ under the load of 1.82 MPa.