Study on the microstructures of polypropylene random copolymer pipe resin
We studied the melt crystallization properties,non-isothermal crystallization behaviors,isotactic polypropylene segment distribution,and crystal morphologies of four types of propylene-ethylene random copolymers(PPR)tube resins,and confirmed that α-phase and γ-phase.The results show that the ethylene content of PPR-1 is 4.2wt%,and the molecular weight distribution(Mw/Mn)is the widest,the crystal content of γ-phase is 57.6wt%,with nucleating agents,and the crystallization is relatively fine and dense;the ethylene content of PPR-2 is 3.9wt%,with the highest Mw,the crystal content of γ-phase is 47.9wt%,with nucleating agents,and the crystallization is the most fine and dense;the ethylene content of PPR-3 is 3.6wt%,with the highest content of long isotactic polypropylene segments,the crystal content of γ-phase is 14.7wt%,without nucleating agents;the ethylene content of PPR-4 is 4.0wt%,the crystal content of γ-phase is 16.7wt%,without nucleating agents.They have similar mechanical properties;the polypropylene process route,ethylene content,and nucleating agent are key factors that cause microstructural differences.
polypropylene random copolymernon-isothermal crystallizationsuccessive self-nucleation and annealing
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