Non-isothermal crystallization kinetics and thermal stability of the in situ reinforcing composite films based on thermotropic liquid crystalline polymer and polypropylene

摘要

The non-isothermal crystallization kinetics and thermal stability of the in situ reinforcing composite thin film, comprising of 10 wt% of thermotropic liquid crystalline polymer (TLCP, Rodrun LC5000) and polypropylene (PP), prepared by a two-step method were investigated using differential scanning calorimetry (DSC) and thermogravimetry (TG), respectively. The DSC results revealed that Mo method was suitable for the crystallization behavior description of both neat PP and 10 wt%TLCP/PP films. The in situ formation of TLCP fibrils in the PP matrix led to reduction in both values of half-time of crystallization (t _1/2) and the kinetic parameter of Mo equation F(T), resulting in a significant increase in the crystallization rate of PP phase. The remarkable lower in crystallization activation energy of the composite films also confirmed that in situ formed TLCP fibrils could influence the molecular chain of PP easier to crystallize, and hence resulted in the faster crystallization rate. The nucleation activity value of composite indicated that TLCP fibrils acted as effective nucleating agents. From TG results and the higher decomposition activation energy, the thermal stability of the composite can be improved by the presence of in situ-formed TLCP fibrils.