Molding Preparation And Modification Of The Rtv Silicone Rubber

Addition-cured room temperature vulcanization silicone rubber has the advantages of favorable handling properties, short setting time, producing no outgrowth, and dimensional stability, which have resulted in its popularity in many industrial fields. However, there are some shortcomings stemming from industrial applications such as, producing air bubble when curing, poor hydrophilicity and the contradiction of viscosity before curing and the strength of cured rubber.In this paper, addition-cured room temperature vulcanization silicone rubber was prepared, which contained the following components: vinyl polysiloxane with vinyl groups both on terminals and in molecule, hydrogen polysiloxane, Pt-catalyst, Vinyl-containing silicone resin, filler, retarder and surfactant. And this paper made improvements aiming at the deficiencies referred.Vinyl polysiloxane was prepared by alkli-catalyzed anionic ring-opening polymerization and used as base gum of addition-cured room temperature silicone rubber; hydrogen polysiloxane of different content of hydrogen was used as cross-linking agents; Pt-catalyst was prepared following Karstedt method as catalyst for hydrosilation. All the components described and other additives were mixed to prepare the base paste of the silicone rubber.Result showed that air bubble when the rubber curing came from the reaction of Si-H and H₂O. And the preventability of air bubble was also investigated. It could be seen that the hydrogen polysiloxane of 0.5wt% hydrogen was the best cross-linking agent and the silica- II was the best filler of different kinds.The filler studied included 3 kinds of silica, 2 kinds of calcium carbonate and 2 kinds quartz powder. Result showed that with the increasing of the filler,...