Investigating on mLLDPE/LDPE/CB composite with PTC

Mlldpe (metallocene catalyzed linear low-density polyethylene)/LDPE (lowdensity polyethy lene)/CB (conductive carbon black) composite with PTC (positive temperature coefficient) effect was successfully prepared by blend. The rheology behavior was investigated through method of rheometer test. PTC strength was tested by resistance measurement, the composite´s morphology and crystallinity was observed by scanning electron microscope (SEM) and scanning electronic microscope (DSC) analysis. The results showed that the most proper blend conditions of the mixing rotation, temperature and time were 30r/min, 453K, 10min respectively. The mLLDPE/LDPE/CB composite had higher PTC strength than that 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%) compared with the traditional PTC polymer (LDPE/CB) while CB was well dispersed in mLLDPE/LDPE composite.