The Preparation of a novel moisture-curing silicone conformal coating

Abstract

In this research, high molecular weight hydroxyl-terminated polydimethylsiloxane (PDMS-OH) was successfully synthesized through a hydroxyl condensation reaction. The optimal reaction conditions included a temperature of 110°C, a reaction time of 4 hours, and a catalyst TMAH amount of 0.08 phr. The structure of PDMS-OH was characterized using nuclear magnetic resonance (1H-NMR) spectroscopy. Subsequently, the PDMS-OH was end-capped with methyl orthosilicate (TMOS) to produce PDMS-TMOS, with a capping agent to hydroxyl group molar ratio of 2:1. The structural analysis of PDMS-TMOS was conducted using Fourier transform infrared spectroscopy (FT-IR) and 1H-NMR. The surface drying time for the moisture-curing coating of PDMS-TMOS was found to be 2 hours at room temperature and 25 minutes at 80 ℃, respectively. The addition of MQ resins to the conformal coatings resulted in a tensile strength of 0.0742 MPa and an elongation at break of 212.7% for the formed film. The coating offers advantages such as a straightforward synthesis process, cost-effectiveness, and high reproducibility, thereby potentially broadening its industrial applications.