Research on preparation technology and properties of mLLDPE/LDPE/CB composite with PTC

mLLDPE(metallocene polyethylene)/LDPE/CB(conductive carbon black) composite with positive temperature coefficient(PTC) was successfully prepared by blending. The rheology behavior and the strength of PTC of the composites were investigated through methods of rheometer test, resistance measurement, scanning electronic microscope (DSC) and scanning electron microscope (SEM) analysis. The results showed that CB can be uniformly dispersed in the mLLDPE / LDPE composite; mLLDPE/LDPE/CB composite has higher strength of PTC than this of the LDPE/CB composite. The PTC mutations temperature of mLLDPE/LDPE/CB composite increased from 358.7K to 377.3K, and also its PTC strength increased from 6.7 to 8.1 with the increasing of mLLDPE content (25wt%~75wt%) to compare with the PTC strength of traditional PTC polymer (LDPE / CB). The proper blend technology conditions of mixing rotation, temperature and time were 30r/min, 453K, 10min respectively.