氢氧化镁的改性及其填充聚丙烯复合材料的燃烧性能和结晶行为的研究

Modification of Mg(OH)_2 and study of flame-retardant property and crystallization behaviors of PP/Mg(OH)_2 composites

研究了硅烷改性齐对氢氧化镁(MH)的表面改性和其填充聚丙烯(PP)复合材料的阻燃性能和结晶行为。用FTIR、XRD和SEM对改性前后MH的结构和形貌进行了分析。结果表明,硅烷处理剂包覆在MH粉体的表面,有效地降低MH粉体的表面能,提高了MH在干态下的分散性。DSC、POM和LOI对PP/MH复合材料的结晶行为和燃烧性能进行了研究。结果表明,未改性的MH对PP有异相成核作用,使结晶峰温度升高;而表面改性剂削弱了填料的异相成核作用。POM结果暗示了MH粒子在基体中的分散性对PP球晶的晶粒形貌和晶粒尺寸起着十分重要的作用。改性后的MH能进一步提高复合材料的LOI。

Magnesium hydroxide （MH）, which-was modified by silane, was filled into polypropylene as a fire retardant. The structure and morphology of untreated and treated MH powders were characterized by FTIR,XRD and SEM. The results show that silane is coated on surface of MH powders and effectively decreases its surface energies. The adsorption between the silane and the surface of MH powders is physical adsorption. SEM shows that the treatment agent improves the dispersion of MH powder in dry condition. The effects of modification agent on the flammability and the crystallization of PP/MH composites were studied by limiting oxygen index （LOI） ,differential scanning calorimetry （DSC） and polarizing optical microscopy （POM）, respectively. DSC data indicates that Mg（OH）2 have heterogeneous nucleation effect on PP matrix. However,silane modifier weakens its heterogeneous nucleation effect. POM results show that the dispersed morphology of MH plays an important role in the crystalline morphology and spherulite size of PP crystals. According to LOI,silane treated MH enhances greatly flame retardancy of PP/MH composite.