The addition of liquid silica gel is a kind of silicone material which is composed of vinyl two methyl siloxane as base polymer, hydrogenated Silicone Fluid as crosslinking agent, and vulcanized into elastomer at room temperature or heating crosslinking agent in the presence of platinum catalyst. Compared to condensed liquid silica gel, the addition of liquid silica gel in the crosslinking process has no byproduct, small shrinkage, deep vulcanization, and no corrosion of contact materials. In recent years, the addition of liquid silica gel has become the fastest growing variety of silicone.
In recent years, the improvement of the mechanical properties of the liquid silica gel and its application and development have received wide attention. The study on the effect of silica on the properties of the liquid silicone has been extensively reported. The hydrogen-containing Silicone Fluid has a great influence on the mechanical properties of the liquid silica gel, and the research on it is relatively small.
Using the same viscosity and hydrogen-containing Silicone Fluid with different content of active hydrogen as crosslinking agent to prepare liquid glue, and to make the vulcanization test piece, the mechanical properties were determined. When the mass fraction of the active hydrogen in the hydrogenated Silicone Fluid is increased from 0.43% to 1.57%, the tensile strength of the liquid adhesive is increased from 4.7MPa to 6.1MPa, Shore A hardness also increases gradually, while the tensile elongation rate from 490% to 255%. This is due to the constant viscosity of the hydrogen-containing Silicone Fluid, with the increase of the active hydrogen mass fraction, the molecular chain segment between the actual crosslinking point becomes shorter, the strength and hardness of the liquid adhesive are decreased, and the elongation rate decreases. When the content of the active hydrogen of the hydrogenated Silicone Fluid increased from 0.75% to 1.57%, the tearing strength was not obvious. This can be explained as follows: when the quality fraction of hydrogen-containing Silicone Fluid is increased to 0.75%, the si-h bond in the cross-linking agent molecule chain is relatively concentrated, resulting in the steric steric effect, which makes the effective crosslinking point of the liquid gum increase not obvious, so that the tear strength of the liquid adhesive changes less.
The effect of different viscosity on the mechanical properties of the liquid rubber was discussed by adding the hydrogen methyl Silicone Fluid in the Liquid Glue Foundation formula. With the increase of the viscosity of the end-hydrogen methyl Silicone Fluid, the tensile elongation and tearing strength of the liquid adhesive gradually increased, while the stretching strength and shore a hardness decreased gradually. This can be interpreted as the increase in the viscosity of the end-hydrogen methyl Silicone Fluid, that is, molecular chain growth, in the reaction with the end of the vinyl Silicone Fluid to increase the molar quality of vinyl silicate oil, in the cross-linking with poly-hydrogen silicon oil, the increase in the molecular chain elongation, tensile strength and hardness decreased.