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以2,6-苯二甲酸环己酰胺(TMB-5)为β晶型成核剂,采用熔融共混的方法制备β晶改性聚丙烯.利用示差扫描量热仪、偏光显微镜、拉伸实验机以及冲击试验机对改性聚丙烯的微观结构、热性能、结晶性能、力学性能进行研究.实验结果表明,在聚丙烯中添加β晶型成核剂进行改性后,由于成核剂在体系中起到了异相成核的作用,聚丙烯中部分晶型由α晶型向β晶型转变,改性聚丙烯的结晶温度向高温方向移动,且聚丙烯球晶尺寸明显减小,球晶之间无明显的边界.随着β晶型成核剂含量的增加,改性聚丙烯的拉伸强度、弯曲强度和弯曲模量呈现先降后升的趋势,而其断裂伸长率和冲击强度呈先升后降的趋势,并且当β晶型成核剂含量为0.4份时,改性聚丙烯的拉伸强度、弯曲强度和弯曲模量为最小值,断裂伸长率和冲击强度达到最大值.
Β-crystalline modified polypropylene was prepared by melt-blending with 2,6-benzenedicarboxylic acid cyclohexamide (TMB-5) as β crystal nucleating agent.Differential scanning calorimeter, polarized microscope, Experimental machine and impact tester were used to study the microstructure, thermal properties, crystallization properties and mechanical properties of the modified polypropylene.The experimental results show that after adding β crystal nucleating agent to polypropylene for modification, In the system, it plays the role of heterogeneous nucleation. Part of the crystalline form of polypropylene changes from α-type to β-type. The crystallization temperature of the modified polypropylene moves to high temperature, and the spherulite size decreases obviously. There is no obvious boundary between spherulites.The tensile strength, flexural strength and flexural modulus of modified polypropylene show the trend of decreasing first and then increasing with the content of β crystal nucleating agent increasing, while the elongation at break And impact strength first and then decrease, and when the β crystal nucleating agent content is 0.4 parts, the tensile strength, flexural strength and flexural modulus of the modified polypropylene are the minimum, the elongation at break and the impact The intensity reaches its maximum.