Polymer blend based on high-density polyethylene for the manufacture of large-sized articles by the quasi-isothermal method

摘要

In the 1960s, in Iomsk Polytechnic University, a quasi-isothermal method was developed for manufacturing large-sized insulation articles from polyolefins. The given method essentially consists in the melting of granulated thermoplastic material in special moulds, without excess pressure in vacuum, and subsequent controlled melt cooling to room temperature. The process lasts 20-300 h and depends on the weight of the article. The very severe processing conditions (high temperature, long holding time of the polymer in melt) make it impossible to use most thermoplastic grades produced. The most effective for the given method for manufacturing large-sized insulation articles is low-density polyethylene (LDPE) of base grade 10803-020 (GOST 16338-77). Insulation articles based on LDPE possess good dielectric properties and satisfactory physicomechanical properties.