Reactivity of Polysilazanes Allows Catalyst free Curing of Silicones

Silicones are typically cured at room temperature by means of metal catalyst such as tin or platinum. When networks are formed the catalyst become unrecoverable, which is of economic as well as environmental concern. Very few methods for producing metal catalyst-free room-temperature vulcanised (RTV) silicones exist and require conditions unavailable in industrial settings. Through the study of organic polysilazane (PSz) reactivity with simple alcohols by NMR, we discovered an unexpected fragmentation preference for breaking the Si-N bond rather than the Si-H; thereby, casting a new light on the fragmentation mechanism of polysilazanes. Utilising the polysilazane fragmentation as a silyl ether coupling agent for multifunctional carbinol silicones, we present a method of producing catalyst free RTV silicone networks at ambient conditions. These silicone networks were proven chemically similar to a standard condensation cured silicone and stoichiometric variations of PSz content demonstrated adjustable network properties.