双酚A型苯并噁嗪树脂/蒙脱土纳米复合材料的制备与表征

为解决苯并噁嗪树脂(BZ)固化温度高和固化后韧性差的问题,首先制备了苯并噁嗪叔铵盐(Bz盐),并通过阳离子交换反应对蒙脱土(Na-MMT)进行改性,得到Bz盐改性蒙脱土(Bz-MMT);其次,将Bz-MMT与BZ共混,通过除泡和加热固化,制备了苯并噁嗪树脂/蒙脱土纳米复合材料(PBZ/Bz-MMT);最后,采用X射线衍射(XRD)、差示扫描量热法(DSC)和热重分析(TGA)等对Bz-MMT、BZ和MMT的混合物以及固化后的PBZ/Bz-MMT纳米复合材料进行分析,分别考察了Bz盐的用量对Bz-MMT层间距和热稳定性的影响、Bz-MMT对BZ的固化温度以及对PBZ/Bz-MMT热稳定性和力学性能的影响.结果表明:随着Bz盐用量的增加,Bz-MMT的层间距基本不变、有机含量提高、起始热分解温度降低;采用Bz-MMT改性BZ,不仅可以降低BZ的起始固化温度,而且能有效地提高PBZ/Bz-MMT的"残炭率"、拉伸强度和冲击强度.

Preparation and characterization of bisphenol A-based benzoxazine/montmorillonite nanocomposites

In order to solve the problems of brittleness and high curing temperature of polybenzoxazines, first, benzoxazine hydrochloride was synthesized with Bisphenol A-based Benzoxazine (BZ) monomer and hydrochloric acid. Second, Bz-MMT was prepared via ion-exchange reaction between Na-montmorillonite (Na-MMT) and benzoxazine hydrochloride, and then was characterized by FTIR, XRD and TGA. Thirdly, curing behavior of the mixture of BZ monomer and Na-MMT, or the mixture of BZ monomer and Bz-MMT, was followed by DSC. Fourthly, polybenzoxazine/montmorillonite nanocomposites PBZ/Na-MMT and PBZ/Bz-MMT were prepared by heating these mixtures of BZ monomer and MMT. Finally, TGA was used to test the thermal stability of PBZ and PBZ/Bz-MMT nanocomposites. The results show that for Bz-MMT, the basal spacing shows no obvious change, organic content increases and the onset decomposition temperture decreases as the amount of benzoxazine hydrochloride added increases. Compared with pure BZ monomer, the onset ring-opening polymerization temperature of the mixture of BZ monomer and Bz-MMT decreases obviously. Compared with PBZ, the char yeild, tensile strength and impact strength of PBZ/Bz-MMT nanocomposites all are increased.