Study on the crosslinking reaction and foaming behavior of silicone rubber in high-pressure fluids

Abstract

High-pressure gas might affect the molecular chain movement, chain interaction, and crosslinking behavior of MVQ during the saturation process. In this paper, by comparing crosslinking exothermic behaviors of MVQ in air, CO₂, and N₂, it is found that the supercritical CO₂ (scCO₂) can promote crosslinking reaction of MVQ through enhancing the swelling and molecular chain's mobility. The result of rheological property shows the competitive relationship between crosslinking and plasticizing effects of MVQ in CO₂. MVQ foams with different cellular structures and porosity are designed by balancing the crosslinking density and plasticization effect. MVQ foams prepared in this study have excellent compressive mechanical properties, and compressive stress can reach up to 1839 kPa at 40 % strain. This paper offers a reference for preparing thermosetting polymer foams in the aspect of crosslinking reaction and cellular structure regulation.