Preparation and Application of Latent Microcapsule Catalysts in One-Component Silicone Rubber Curing

Abstract

A latent microencapsulated catalyst (LMC) is a promising material to prepare one-component silicone rubber curing in industry. In this study, polystyrene (PS) with varying molecular weights and narrow molecular weight distributions (1.07−1.44) was meticulously synthesized via atom transfer radical polymerization (ATRP). Then, the synthesized PS was used as the wall material and a Karstedt catalyst was used as the core material to prepare different sizes of LMCs with a core content of about 20 wt % by a solvent evaporation method. The chemical structure, surface morphology, and core content of the prepared LMCs were characterized. Furthermore, the curing characteristics of onecomponent silicone rubber with different LMCs were investigated. Comparative analysis revealed that LMCs prepared from PS derived via ATRP exhibited superior attributes compared to those generated using commercially available PS, including a smaller particle size, more concentrated particle size distribution, heightened thermal responsiveness to temperature fluctuations, accelerated curing rate, and prolonged room temperature latency. Notably, the ATRP-derived LMCs demonstrated exceptional stability, ensuring steady storage with a latent period exceeding 2 months at room temperature.