Influence of Alkynyl Phosphite Ligands on the Curing of Pt(0)-Catalyzed Preparation of One-Component Silicone Rubber

Abstract

The development of wide-range temperature-stabilized catalysts for one-component silicone rubber is challenging because the high room temperature activity of Karstedt's catalyst greatly diminishes the storage stability period of one-component silicone rubber. In this work, three catalyst ligands were constructed based on a transesterification reaction between alkynyl alcohols and phosphite, then were complexed with Karstedt's catalyst. The results of research and testing showed that the platinum-alkynyl phosphite catalysts have better room temperature stability, in which the catalyst synthesized with the ligand tris(trimethyldodecynyl) phosphite (L2) enabled the silicone rubber to be stored at room temperature for more than 30 days and cured rapidly at 120 °C. Adding this catalyst not only preserved the original performance properties of silicone rubber but also enhanced its thermal stability and mechanical properties. The ligand acted as a substituent to complex with Karstedt's catalyst to inhibit its activity, thus solving the problem of poor storage stability of one-component silicone rubber at room temperature.