Sustainable catalysts for filled and unfilled silane cross-linked polymer systems

Abstract

Since the polymer used to make up cables is combustible and has the potential to ignite a fire, fire safety concerns about cables receive a lot of attention. This concern prompts an urgent need to address safety issues and drives the global development of flame retardant polymeric systems. Dioctyltin dilaurate (DOTL) is an organotin catalyst that is frequently used in silane cross-linking for flame retardant polymeric systems. However, DOTL is toxic and has a reprotoxic impact on humans. This study focuses on investigating robust and sustainable catalysts which can be utilized for various silane cross-linked polymeric systems to replace DOTL. Both filled and unfilled silane cross-linked polymer systems were investigated with various types of catalysts, including four polymer systems (Polymer A, B, C, and D) and four catalysts (Catalyst 1, 2, 3, and DOTL as reference). Tapes made with various amounts of polymer base resin and catalyst masterbatch were crosslinked in ambient conditions and hot water baths. Two analytical techniques, XRF and FTIR, were used for analyzing catalyst masterbatches. Visual observation was utilized to evaluate tape surface quality. The crosslinking of different tapes was measured by hot set testing method. The results showed that when catalyst 3 is extruded with the unfilled polymer A, highly filled polymer B and C, tapes showcased very good surface qualities and good cross-linking in ambient conditions. The catalyst also displayed good cross-linking in hot water bath for polymer A and C. Catalyst 1 and 2 cross-linked unfilled and some filled polymer systems in hot water bath and ambient conditions but the tapes had bad surface qualities.