Synthesis of a New Liquid Crystalline Polymer as a Highly Active beta-Nucleator and Its Effect on Melting and Crystallization Behaviors of Isotactic Polypropylene

摘要

A new nematic liquid crystalline polymer as a highly active beta-nucleator (LCP-N) of isotactic polypropylene (iPP) was synthesized and characterized. The effect of LCP-N on thermal behavior of the iPP was investigated with differential scanning calorimetry. LCP-N showed a melting transition at 85.0 degrees C and a nematic to isotropic phase transition at 278.0 degrees C. The incorporation of LCP-N could lead to substantial changes in the thermal behavior of the iPP. The nucleating activity of LCP-N mainly depended on its content, mesogenic molecular structure, and thermal history of processing. A high content of beta-form could be obtained by the combined effect of the optimum LCP-N concentration and crystallization temperature and time. The Phi(beta) reached 77% when the LCP-N content, crystallization temperature, and crystallization time were 0.4 wt.%, 125 degrees C, and 1 h, respectively.