高浓度硅溶胶与纳米SiO_2粉体对聚丙烯结构和性能的影响

Effect of High Concentrations of Silica Sol and Nano Silica Powder on the Structure and Properties of Polypropylene

通过双螺杆挤出机实现了高浓度硅溶胶、纳米二氧化硅分别与聚丙烯(PP)的熔融共混,制备了PP/高浓度硅溶胶和PP/纳米Si O2的复合材料。利用差示扫描量热、透射电镜、电子探针及力学性能测试分别分析了高浓度硅溶胶及纳米Si O2粉体的含量对PP结晶性能、分散性及力学性能的影响。结果表明,与纳米Si O2粉体相比,高浓度硅溶胶更加纯净,与PP共混不会引入杂质,且在PP中分散更均匀。高浓度硅溶胶与纳米Si O2粉体的加入,都能提高PP的拉伸、弯曲和缺口冲击强度,并使PP的结晶度增大和结晶温度升高,但高浓度硅溶胶改性PP优于纳米Si O2粉体。当高浓度硅溶胶添加量为3%时,PP复合材料的缺口冲击强度达最大值,为4.49 k J/m2,纳米Si O2添加量为3%时,PP的缺口冲击强度达最大值,为4.43 k J/m2。

The composites of polypropylene( PP) / high concentration of silica sol and pp / nano-Si O2 powder were prepared through twin-screw extruder. The effects of the high concentration of silica sol and nano silica powder on the crystallization behavior,dispersion and mechanical properties were investigated by DSC,TEM,electron probe and mechanical properties testing. Results show that the addition of high concentration of silica sol introduces no impurities and has better dispersion in PP matrix compared with the addition of nano-Si O2 powder. With the high concentration of silica sol,nano silica powder added into PP matrix,respectively,the tensile strength,flexural strength and notched impact strength of PP increase,moreover the crystallization temperature and the crystallinity also increase. But the PP / high concentration of silica sol composites have better mechanical properties than the PP / nano-Si O2 powder composites. The notched impact strength of PP / high concentration of silica sol composites and PP / nano-Si O2 powder composites reaches the maximum,respectively,which is 4. 49 k J / m2 and 4. 43 k J / m2,when the content of high concentration of silica sol and nano-Si O2 powder is 3%.