The response of carbon black filled high-density polyethylene to microwave processing

Microwave processing has numerous advantages over traditional methods of heating. Most thermoplastics, such as high-density polyethylene (HDPE), are nearly transparent to electromagnetic radiation. Carbon black (CB) filled HDPE was prepared in order to improve the microwave heatability of HDPE. The heating response of HDPE/CB composites to microwave exposure and the effects of this exposure on the mechanical and physical properties of material were investigated. The addition of CB particles improved the microwave heatability of HDPE, and microwave heatability of composites varied with CB content, in which an average temperatures of up to 139 °C above ambient were measured for 20 wt% CB composites after a exposure duration of 150 s. Microwave exposure had no obvious effect on rheological property of HDPE/CB composites. Mechanical properties of HDPE/CB composites are relatively improved after microwave exposure. Scanning electronic micrograph (SEM) analysis presented that the interface defects between CB particles and HDPE matrix are significantly reduced and a better combination was found after microwave exposure. Differential scanning calorimetry (DSC) analysis showed that the melt point of HDPE with CB shifted toward high temperature and degree of crystallinity increased after microwave exposure.