阻燃OMMT/WPU纳米复合材料的制备及性能

Preparation and properties of flame-retardant OMMT/WPU nanocomposites

采用端羟基聚丁二烯(HTPB)剥离层状有机蒙脱土(OMMT)为纳米片,并与异佛尔酮二异氰酸酯(IPDI)、二羟甲基丙酸(DMPA)等单体通过原位聚合法制备了OMMT纳米片改性的水性聚氨酯(OMMT/WPU)纳米乳液。利用小角XRD、TEM、DLS、EDS、TGA、SEM、锥形量热及极限氧指数测定方法对样品的结构和性能进行了表征。结果表明,HTPB剥离的OMMT纳米片的衬度均匀,完整性较好;改性后OMMT/WPU乳液的粒径增大,胶膜的弹性模量、热稳定性、抗熔滴性和阻燃性能均得到明显改善,其中弹性模量可提高约59.4%,热释放速率峰值可降低约36.9%;燃烧炭渣表面形貌显示,瓦片状蒙脱土相互穿插形成了具有团簇结构的蒙脱土覆盖层。

Layered organic montmorillonite(OMMT) was exfoliated into nanosheets by hydroxyl-terminated polybutadiene(HTPB). Then OMMT nanosheets modified waterborne polyurethane(OMMT/WPU) emulsions were by in situ polymerization using isophorone diisocyanate(IPDI) and dimethylolpropionic acid(DMPA) and so on as raw materials. The structure and properties of the samples were characterized by small-angle XRD, TEM, DLS, EDS, TGA, SEM, conical calorimetry and limiting oxygen index measurement. The results suggested that the OMMT nanosheets had uniform contrast and good integrity. After modification, the particle size of emulsion increased, the elastic modulus, thermal stability, droplet resistance and flame retardant properties of film obviously improved. Particularly, the elastic modulus of OMMT/WPU nanofilm was increased by about 59.4% and peak heat release rate was decreased by about 36.9%. The surface morphology of the burning char residue showed that the tile-shaped OMMT interpenetrated into each other to form a montmorillonite covering layer with cluster structure.