Effect of carbon black incorporation methods on the initial creep/slow crack growth resistance and properties of high-density polyethylene (HDPE) pipes

Abstract

The increasing utilization of polyethylene (PE) pipes in diverse industries has driven a focused exploration into the properties and behaviors of PE materials. In response to this heightened interest, this study aims to investigate the impact of different carbon black (CB) incorporation methods on the properties of PE100 polyethylene, particularly its resistance to slow crack growth (SCG). Two distinct methods, direct incorporation and utilization of a commercial masterbatch, were employed to introduce CB into the PE100 matrix. Results revealed that direct incorporation led to superior dispersion of CB, thereby enhancing the mechanical properties of the resultant compound. Furthermore, SCG resistance exhibited improvement when CB was directly incorporated, contrasting with a degradation in SCG resistance observed when a CB masterbatch was used compared to neat PE. Comprehensive rheological and thermal analyses were conducted to elucidate these findings. The study concludes that the presence of low molecular weight substances and inadequate CB dispersion within the CB masterbatch significantly contributed to the deteriorated SCG resistance observed in PE100 material.