氢氧化镁阻燃剂填充EVA共聚物力学性能研究

研究了普通氢氧化镁、六角片状氢氧化镁和硬脂酸(SA)改性氢氧化镁分别填充到乙烯-乙酸乙烯共聚物(EVA)中制得的复合材料的力学性能。用红外光谱(FT-IR)、扫描电镜(SEM)对3种类型氢氧化镁及EVA/氢氧化镁复合材料的结构和形貌进行了分析。结果表明:相比普通氢氧化镁,六角片状氢氧化镁和SA改性的氢氧化镁有效地降低了表面极性,大大降低了对复合材料的力学性能的影响;4%(质量分数)SA改性氢氧化镁在EVA树脂中的分散性均匀,填料表面与树脂表面的界面黏结性较好;氢氧化镁(MH)粉体的加入增加了EVA/MH复合材料的拉伸强度,其中4%(质量分数)SA改性氢氧化镁粉体对复合材料拉伸强度的影响最大,六角片状氢氧化镁影响最小;氢氧化镁粉体填充量达到60质量份(60质量份氢氧化镁填充至100质量份EVA中)时,断裂伸长率降低到100%以下,复合材料力学性能急剧恶化。

Study on mechanical properties of ethylene - vinyl acetate (EVA) copolymer stuffed by magnesium hydroxides flame retardants

Examined mechanical properties of ethylene-vinyl acetate(EVA) copolymer stuffed by different types of magnesium hydroxide including a general purpose grade,a stearic acid(SA) modified grade and a hexagonal flake.Structures and morphologies of the three types of magnesium hydroxide and EVA/ Mg(OH)2 composites were analyzed by FT-IR and SEM.Results showed that the hexagonal and SA modified types of magnesium hydroxide effectively decreased surface polarity while markedly reduced mechanical property loss of the composites compared with the general purpose grade magnesium hydroxide.Dispersion and compatibility of magnesium hydroxide in EVA copolymers were improved by modifying the magnesium hydroxide with 4%(mass fraction) of stearic acid.Such modified magnesium hydroxide yielded a maximal effect on the tensile strength of the composites,while same effect being minimal for hexagonal magnesium hydroxide.The elongation at break reduced below 100% and the mechanical properties of composites deteriorated rapidly when the stuffing of magnesium hydroxide reaches 60 phr(per hundred rubber).