改性MCA/尼龙6无卤阻燃复合材料的原位合成及阻燃机理研究

Melamine cyanurate (MCA)/nylon 6 flame retardant composite poccesses excellent non-halogen flame retardant characteristics, yet, as MCA is commonly synthesized using water as the reaction media, large amount of wastewater might be discharged, meanwhile, the flame retardant properties of MCA decrease because of the wick effect in reinforced nylon 6 composites, and the investigation on flame retardant mechanism of this flame retardant and its composites is not so systematic. To solve these problems, molten ε-caprolactam is used as the media for the preparation and modification processes of MCA, and silica sol is introduced as a modifier to capsule MCA while controlling its diameter and optimizing its surface properties, and then, modified MCA/nylon 6 composites are prepared by in-situ polymerization. Based on the study on the structure and properties of modified MCA and flame retardant nylon 6 composites, the effect of processing parameters can be examined, while, the synthesis and modification of MCA, polymerization mechanism of nylon 6 at the presence of modified MCA, and flame retardant mechanism will be investigated. Through this research, key technical breakthroughs can be made in the synthesis of non-halogen flame retardant nylon 6 composites, excellent flame retardant nylon 6 composites can be prepared using an environment-friendly method, and the interaction of different components in the matrix can be clarified, which is helpful for further optimization of synthesizing technology.

三聚氰胺氰尿酸盐（MCA）/尼龙6阻燃复合材料具有良好的无卤阻燃特性。但该材料研究中尚存在MCA传统合成以大量水为反应介质造成水资源浪费和废水排放、增强尼龙6体系中MCA阻燃性能由于“烛芯效应”而大幅度降低、复合材料阻燃机理研究有待进一步深入等问题。本项目在熔融己内酰胺中合成MCA，并引入SiO2溶胶对其粒径与性能进行优化调控，继而原位合成改性MCA/尼龙6阻燃复合材料。通过研究材料的结构与性能，得出改性MCA及阻燃尼龙6复合材料制备的最佳参数及相关机制、阻燃尼龙6的阻燃机理，有望在无卤阻燃尼龙6制备关键技术取得突破，制备性能优异的阻燃尼龙6复合材料，且制备工艺可实现资源节约和环境友好，同时可探析材料体系中复合组分相互作用机制，为进一步优化制备技术打下理论基础。

为解决传统的以水为介质合成三聚氰胺氰尿酸盐（MCA）工艺引起的大量水资源浪费和大量污水的不足，以及MCA的加入而造成MCA阻燃尼龙6复合材料的力学性能下降和增强MCA/尼龙6复合材料的“烛芯效应”等问题，本课题以熔融己内酰胺作为MCA的合成反应介质，在合成过程中加入二氧化硅溶胶，改性MCA，继而原位聚合，制备改性MCA/尼龙6无卤阻燃复合材料，实现整个过程的资源节约和环境友好，在阻燃剂含量达到7 wt%时，所制备的复合材料的阻燃性能达到UL 94 V-0级，力学性能得到明显改善。重点研究了熔融己内酰胺中改性MCA的合成工艺和结构之间的关系，改性MCA存在下原位聚合制备尼龙6的工艺，改性MCA/尼龙6无卤阻燃复合材料的结构、性能以及阻燃机理等。结果表明：正硅酸乙酯在熔融己内酰胺中可以水解，在不调整pH值，水解温度为90 ℃，时间为4小时，SiO2溶胶添加量为MCA的10 wt%时改性效果最佳。尼龙6的最佳合成工艺为在改性MCA存在下，在250 ℃和0.6MPa聚合6小时，然后在250 ℃和-0.1MPa聚合2小时，得到高分子量的尼龙6阻燃复合材料。这种方法保证了MCA粒子的粒径控制和表面性能的改善，实现了改性MCA粒子在尼龙6基体中的良好分散和界面结合，同时得到了高分子量的尼龙6，与纯尼龙6相比，阻燃尼龙6复合材料的拉伸强度提高了3%，极限氧指数提高了45.9%（达到35），复合材料的阻燃机理为凝聚相阻燃和气相阻燃的双重作用。研究成果为资源节约和环境友好工业化生产无卤阻燃尼龙6复合材料提供了重要的参考。已发表标注有本项目资助的论文4篇（其中SCI和EI各1篇），获授权中国专利1项，参加国内学术会议4人次，培养硕士研究生2名。