苯乙烯接枝改性对聚丙烯发泡质量的影响OA

The melt strength of polypropylene(PP)had a significant influence on foaming quality,and substantially improving its melt strength through simple methods was of great importance.In the study,styrene(St)was employed as the grafting monomer,and high melt strength polypropylene(HMSPP)was prepared via melt blending.The effects of St monomer on the melt flow rate,rheological properties,crystallization behavior,and foaming quality of PP were investigated.The results indicated that higher grafting degrees of St monomer led to lower melt flow rates of the products.The melt flow rate decreased from 103.6 g/10 min to 83.4 g/10 min upon the addition of St monomer,and the St monomer significantly enhanced the melt strength of PP.Furthermore,the products added St monomer exhibited higher complex viscosity and storage modulus,along with a smaller loss angle.Scanning electron microscopy results revealed that St monomer could markedly improve the foaming quality of PP.HMSPP3,which possessed the highest St monomer grafting degree,maintained excellent cell morphology with high uniformity and high density even at 200℃.The cell density increased from 8.14×106 cells/cm3 to 1.59×107 cells/cm3,while the average cell size decreased from 80 μm to 59 μm.Compared with PP,HMSPP3 with the highest grafting degree demonstrated superior foaming performance.