膨胀剂修饰的阴阳黏土在橡胶中的协效作用

Synergism between intumescent flame retardants modified anion and cation clays in rubber

分别采用对硝基苯甲酸和三聚氰胺磷酸盐作为膨胀阻燃剂组分有机修饰阴阳离子黏土:层状双氢氧化物和蒙脱土.将有机修饰的层状双氢氧化物(OLDH)和有机修饰的蒙脱土(OMMT)与超微氢氧化镁(HFMH)一起作为无卤阻燃剂,通过熔融插层法,加入到丁腈橡胶(NBR)中,制备无卤阻燃NBR/OLDH/OMMT/HFMH纳米复合材料.采用傅里叶红外光谱、X射线衍射、透射电镜、热重分析、氧指数、垂直燃烧和力学测试研究NBR/OLDH/OMMT/HFMH纳米复合材料的形态结构、协效作用、热和力学性质.结果表明能够得到剥离或插层的纳米复合材料,且OLDH和OMMT均匀分散在NBR基体中.归于膨胀阻燃剂组分有机修饰的OLDH和OMMT的协效作用,含有5份OLDH和5份OMMT的NBR-3在700℃有最高的残碳量.NBR-3样品主链的热稳定性比NBR-5样品(含有10份OMMT)和NBR-1样品(含有10份OLDH)的高15～18℃.在所有的样品中,NBR-3样品的氧指数最高,为38%.样品NBR-2、NBR-3、NBR-4均能通过V-0级.力学性能表明有机修饰的纳米片层能够明显地提高样品的拉伸强度和100%伸长时应力.

The p-nitrobenzoic acid（NBA） and melamine phosphate（MP） were used as intumescent flame retardant ingredients to modify anion and cation clays： layered double hydroxide（LDH） and montmorillonite（MMT）,respectively.The organically modified OLDH and OMMT acted with the hyperfine magnesium hydroxide（HFMH） as halogen-free flame retardant in NBR/OLDH/OMMT/HFMH nanocomposites.The structural characterization,synergistic effects,thermal and mechanical properties of the NBR/OLDH/OMMT/HFMH nanocomposites were studied by fourier transform infrared spectroscopy,X-ray diffraction,transmission electron microscope,thermogravimetric analysis,limiting oxygen index（LOI）,UL-94 and mechanical test.The results showed that the exfoliated or partly intercalated NBR/OLDH/OMMT/HFMH nanocomposites could be obtained,the OLDH and OMMT could disperse homogeneously in the NBR matrix.Due to the synergistic effect of intumescent flame retardant ingredients organically modified LDH and MMT,the NBR-3 sample with 5 phrs OLDH and 5 phrs OMMT had the highest char residues（40.7%） at 700 ℃.The NBR chain of NBR-3 sample was 15-18 ℃much stabler than those of NBR-5 with 10 phrs OMMT and NBR-1 with 10 phrs OLDH samples.The NBR-3 sample with the highest LOI value of 38 was obtained.The samples NBR-2,NBR-3,NBR-4 passed the V-0 rating.The organically modified nano layers could clearly improve tensile strength and stress at 100% elongation of the samples.