改性微胶囊化聚磷酸铵阻燃天然橡胶

Modified Microencapsulated Ammonium Polyphosphate Flame Retardant Natural Rubber

摘要:

本文通过原位聚合法制备了聚乙烯醇（PVA）改性的三聚氰胺（MEL）-甲醛树脂（VMF）微胶囊，对聚磷酸铵（APP）/介孔分子筛MCM-41进行包覆，得到了一种新型的核壳结构的微胶囊阻燃剂（MVMF-(A/M)）。通过红外光谱分析（IR）、溶解度和扫描电子显微镜（SEM）对包覆前后的阻燃剂结构以及形貌进行表征。并将其加入到天然橡胶（NR）中，通过氧指数测试（LOI）、垂直燃烧测试（UL-94）、热失重分析（TG）、拉伸测试研究了NR复合材料的阻燃性能和力学性能。实验结果表明：制备的MVMF-(A/M)在20℃水中的溶解度为1.59mg /L，相比APP溶解度降低51.2%， MVMF-(A/M)粒子表面变得粗糙；与其他阻燃天然橡胶体系相比添加了MVMF-(A/M)的NR复合材料的极限氧指数最高， UL-94达到了V-0级别，拉伸强度为8.84MPa，断裂伸长率为310.20%。

Abstract:

In this paper, melamine (MEL) - formaldehyde resin (VMF) microcapsules were modified by polyvinyl alcohol (PVA) through in situ polymerization. Then the poly ammonium polyphosphate (APP) / mesoporous molecular sieve MCM-41 were coated by the prepared material, and thus a kind of flame retardant (MVMF-(A/M))with novel core-shell structure was prepared. The structure before and after microencapsulating was characterized by infrared spectrum analysis (IR), solubility test and electron microscope scanning (SEM). In addition, the flame retardant was added into natural rubber (NR) and the flame retardancy and mechanical properties of NR composites were tested by oxygen index (LOI), vertical burning test (UL-94), thermal gravimetric analysis (TGA), tensile test. The results showed that the solubility of prepared MVMF- (A/M) is 1.59mg /L in 20 ℃ water, was decreased by 51.2% compared with APP. Meanwhile, MVMF- (A/M) particle surface became rough; compared with other flame retardant system, the limited oxygen index value of the limited oxygen index value of NR- MVMF- (A/M) composites to be maximized, samples could pass the V-0 rating in the UL-94 tests; the tensile strength of samples reached 8.84MPa and its elongation at break reached 310.20%.