Synergistic nucleation effect of calcium sulfate whisker and β-nucleating agent dicyclohexyl-terephthalamide in isotactic polypropylene

The crystallization and melting behaviors and mechanical properties of isotactic polypropylene (iPP) containing a certain amount of stearic acid-modified calcium sulfate whiskers (S-CSW) and dicyclohexyl-terephthalamide (TMB-5) were investigated. The results revealed that S-CSW and TMB-5 had obvious synergistic nucleation effect in iPP. At the optimum addition concentration, the crystallization peak temperature of nucleated iPP increased by 8.1 degrees C compared with that of pure iPP, and the relative content of beta-crystals in iPP reached to 0.9012. The impact strength, tensile strength and flexural modulus of iPP increased by approximately 61.8%, 1.71% and 26.1%, respectively, which were obviously better than that of iPP nucleated with S-CSW or TMB-5 independently.