成核剂对聚丙烯结晶形态及力学性能的影响

分别以HPN-68 L,NA-21,苯甲酸钠(NA),A1为成核剂,采用熔融混合法对聚丙烯(PP)进行改性。利用偏光显微镜,差示扫描量热仪(DSC)和万能材料试验机考察了成核剂的种类和用量对PP的结晶形态、热性能和力学性能的影响。结果表明,分别添加几种成核剂后PP的结晶温度明显提高,晶体尺寸减小,弯曲强度和弯曲模量明显增大,拉伸模量略有提高,但拉伸强度未发生明显变化,断裂伸长率降低;成核剂A 1与HPN-68 L对PP力学性能的影响相当,但添加前者PP的结晶温度略低于添加后者的。

Effect of nucleating agents on crystalline morphology and mechanical properties of polypropylene

Polypropylene （PP） was modified by melt - blending method with HPN - 68 L, NA - 21, NA （sodium benzoate） and A 1 （developed by Institute of Chemistry, Chinese Academy of Sciences） as nucleating agent respectively. The influences of the type and amount of nucleating agents on the crystalline morphology, thermal and mechanical properties of PP were investigated by polarizing microscope, differential scanning calorimeter and universal testing machine. The results showed that after the nucleating agents were added the crystallization temperature of PP increased,the crystal size decreased,the bending strength and modulus increased significantly, the tensile modulus slightly increased, the tensile strength had no evident change and the elongation at break decreased. The influence of nucleating agent A1 on the mechanical properties of PP was similar to that of HPN -68 L, but the crystallization temperature of PP with A 1 was lower than that with HPN -68 L.