Study on the preparation and performance of low gas permeability trifluoropropyl phenyl silicone rubber

In order to overcome the defects of opacity, high gas permeability, poor heat and solvent oil resistance of methyl silicone rubber, optically transparent trifluoropropyl phenyl silicone rubber was prepared by introducing trifluoropropyl and phenyl to organic silicone molecules. Then organic polysilazane (OPSZ) was coated on the trifluoropropyl phenyl silicone rubber surface with tetramethylhexamethylenediamine as a catalyst and a dense coating with low gas permeability was achieved. This process realized low-temperature curing and siliceous transition. At the same time, optical performance, mechanical properties, oxygen permeation flux, and anti-sulfuration were measured. The results showed that the fluorine-containing phenyl silicone rubber had good optical transparency, tensile strength, elongation at break, tear strength, oil resistance and heat resistance. The OPSZ coating surface was continuous, uniform, dense and free of cracks and voids; meanwhile, the coating section was dense, uniform, seamless, without cracks. The interface between the coating and the silicone rubber exhibited good adhesion. Light transmission was over 92% between 400 and 800 nm. When the coating thickness was more than 12 μm, the oxygen permeation flux remained unchanged, lamps had good anti-sulfuration ability, and luminous flux was maintained at over 99.8%. when the mass fraction of tetramethyl hexamethylene diamine ( w ) was over 5%, siliceous transition was achieved under room temperature and 50% relative humidity for 24 h. Low gas permeability coating can prevent oxygen and sulphur vapour from permeating into silicone rubber and protect electronic components, chips, electrodes, medicines, etc. from oxidation and sulfuration.