Controllable Silicone Rubber Curing via Controlled Release of Homogeneous Pt from a Metal–Organic Framework-Based Capsule

Platinum-based hydrosilylation catalysts are primarily applied in the curing of silicone rubber. However, the commercial Karstedt catalysts used in industrial applications seriously suffer from rapid oxidation in air, uncontrolled activity at room temperature, rigorous storage conditions yet short pot-life, poor thermal stability, and complicated operation packages. Herein, Pt@MOFs, constructed by immobilizing catalytically active sites Pt inside the pores of a metastable MOF-based host with selected decomposition temperature, acts as a "controlled-release MOF-based capsule" to keep a long pot-life during storage and transport at ambient conditions, control the curing temperature of hydrosilylation, and releases the catalytically active Pt sites at required temperature for in situ polymer formation. Additionally, the unique nanosized crystalline MOF carriers are dominant for uniform dispersion in polysiloxanes and guarantee the excellent oxidation resistance in the Pt@MOFs catalytic system, which provides a new generation catalyst for widely used silicone rubber packages and an innovative pathway for the application of metastable MOF materials. Honeywell® has initiated kilogram-scale silicon rubber packages with Pt@MOFs.