Influence Principle of Mechanical Properties of Additional RTV Silicone Rubber

The additional room temperature vulcanizing silicone rubber was prepared by using polydimethyl siloxane terminated by vinyl group as basic components,hydrogen-containing silicone oil as a cross-linking reagent and the complex pound of platinum and divinyltetramethyl disiloxane as catalyst.The effect of the viscosity of basic components,the hydrogen content of hydrogen-containing silicone oil,the filler amount and the A value(the ratio of Si—H/SiCH=CH2 of hydrogen-containing silicone oil and vinyl silicone oil) on the properties of silicone rubber were experimentally examined.Results showed that the tensile strength,the elongation and the tear strength appeared maximum values respectively as the viscosity of basic components was increased.The hardness of the silicone rubber was increased and then decreased with the increase of additional filler.The vulcanized silicone rubber was of excellent mechanical properties while the viscosity of the vinyl silicone oil was 5 Pa·s,and the treatment of fumed silica was about 25 phr(based on vinyl silicone oil consumption),and A value was between 1 and 3.6.Using the above vinyl conditions described a silicone rubber of Shore A hardness of 34 degrees,the tensile strength of 4.78~5.09 MPa,the tear strength of 4.97 kN/m and elongation rate of 107 % was obtained.