Solid curing agents for polyurethane foams: Proof of concept of the release mechanism

We show the first evidence that the microporous GreenCaps organosilica microspheres, functionalized with glycerol and sprayed from a pressurized one component polyurethane foam completely break and release their functional payload, thereby noticeably increasing the rate and the extent of the foam's curing. Further positive results concerning the main froth parameters used by urethane foam manufacturers in the presence of the GreenCaps confirm the potential of these materials to cure better and greener spray polyurethane foams. Sprayed from an aerosol can pressurized at 6 bar, GreenCaps organosilica microspheres functionalized with glycerol break into small fragments due to sudden depressurization, releasing the encapsulated polyol. Coupled to their leach-proof nature when mixed with the polyurethane precursor mixture, this opens the route to practical use of the GreenCaps to rapidly cure greener spray PU foams.