A new method for the determination of a hydrosilanization inhibitor applied to measurements during curing of a silicone elastomer

A new method for the quantitative determination of the hydrosilylation inhi bitor 1-ethynyl-1-cyclohexanol in a poly(dimethyl siloxane) matrix is prese nted. The method is based on headspace gas chromatography directly from the semisolid sample without solvent addition. The method was found to be both selective and sensitive. The relative standard deviation of the method was estimated to be 6%. The semisolid silicone sample was weighed directly in a headspace autosampler vial. After sample equilibration at 90 degreesC for 1 h, the gas phase was injected into a gas chromatography system with a no npolar methyl silicone capillary column. The inhibitor was detected with a flame ionization detector. The standard addition procedure was used for qua ntification. Recovery data on the inhibitor from the silicone during curing suggests that the inhibitor reacts with the silicone hydride crosslinker i n the presence of the platinum catalyst to become part of the polymer netwo rk. This implies that the inhibitor will not migrate out from the silicone elastomer, which is a great advantage particularly for silicone elastomers used for medical devices or controlled drug release applications. (C) 2001 John Wiley & Sons, Inc.