无卤阻燃尼龙纳米复合材料微观结构对流变行为及阻燃性能的影响

Effect of Microstructure of Halogen-Free Flame-Retarded Nylon Nanocomposites on Rheological Behavior and Flame Retardancy

通过熔融共混法制备3种不同蒙脱土/尼龙6及蒙脱土/阻燃尼龙6复合材料,采用X射线衍射、透射电子显微镜、旋转流变仪以及接触角测量对样品结构进行了系统表征,并采用氧指数测试、垂直燃烧及锥形量热仪对复合材料的阻燃性能和燃烧行为进行测定。探讨和比较了不同蒙脱土与聚合物的相互作用对阻燃纳米复合材料结构、流变行为及阻燃性能的影响。结果表明,蒙脱土与聚合物的界面张力越小,界面亲和性越好,蒙脱土在聚合物中的分散性越好。对于阻燃聚合物纳米复合材料,蒙脱土与聚合物强的相互作用可显著改善蒙脱土在体系中的分散分布,体系中分散良好的蒙脱土片层在空间形成了三维粒子网络,使整个大分子体系呈现出"类固"流变响应,改善了熔体稳定性,从而有效改善了材料的燃烧行为。

Three kinds of montmorillonite/nylon 6 and montmorillonite/flame-retarded nylon 6 composites were prepared by melt blending. The structure of the samples was characterized by XRD, TEM, rotational rheometer and contact angle measuring instrument. The flame retardant properties and the combustion behavior of the composites were measured by limiting oxygen index （LOI）, vertical burning test （UL-94） and cone calorimeter. The effects of the interaction between different montmorillonite and polymer on the structure, rheological behavior and flame retardancy of flame-retarded nanocomposites were investigated and compared. The results show that the smaller inteffacial tension of montmorillonite and polymer results in the better affinity and the better dispersibility d montmorillonite in the polymer. The interaction between montmorillonite and polymer can significantly improve the dispersion of montmorillonite in the flame-retarded polymer nanocomposites, and the well-dispersed montmorillonite layers in the system form three-dimensional particle network in the space. The macromolecular system presents a ＂solid-like＂ rheological response, which improves the melt stability and ultimately improves the combustion behavior of the material.