硬脂酸改性Mg(OH)2的机理及对EVA性能的影响

采用FTIR表征硬脂酸对氢氧化镁Mg(OH)₂的改性效果，发现不存在一个所谓的“最佳量”，分析认为硬脂酸对Mg(OH)₂表面改性既包括着 硬脂酸—COOH与Mg(OH)₂的—OH之间的弱酯化反应，也包含着酸与弱碱Mg(OH)₂之间的酸碱反应，所以硬脂酸对Mg(OH)₂的表面改性随硬脂酸用量 增加而持续进行。此外，改性剂用量也对Mg(OH)₂填充乙烯-醛酸乙烯酯共聚物(EVA)体系性能存在显著的影响。与填充未处理Mg(OH)₂体系相比 较，表面改性剂用量的增加会导致复合材料的拉伸强度的不断下降，断裂伸长率的增加和阻燃性能的急剧恶化。但是，复合材料的表观黏度下 降，加工性能得到改善。

Mechanistic studies of the effect of stearic acid coated Mg(OH)2 on properties of EVA/Mg(OH)2 composites

In this paper,FTIR spectroscopy was employed to evaluate the effect on Mg(OH)_2 of coating the surface with stearic acid.It was found that there was no one optimum loading.It is proposed that the surface modification involves two important processes: one is a type of weak esterification and the other is the acid-base interaction between stearic acid and Mg(OH)_2.Both these reactions were favored by increasing the amount of stearic acid.Moreover,the amount of surface modifier had a significant influence on the properties of EVA/Mg(OH)_2 composites.A continuous decrease in tensile strength and increase in elongation at break of the composites were observed with increasing amount of stearic acid.Meanwhile the flame retardancy of the composites was poorer however compared with that of composites filled with uncoated Mg(OH)_2.However,surface modification of Mg(OH)_2 by stearic acid facilitated the processing of the composites.