Preparation And Application Of MQ Silicon Resin

Silicone rubber has good weather resistance,radiation resistance,aging resistance,heat resistance and cold resistance and other characteristics,which arise lot concern and is widely used in industrial,aviation and medical fields.In this experiment,molecule-weight-controllable MQ silicone resin were synthesized in the first place,then which was used to synthesize two kinds of vinyl-controlled VMQ silicone resin.VMQ silicon resin is used to prepare high strength and transparent silicon rubber.As follows:TEOS,H₂O,H₂SO₄,IPA and MM are used as raw material,make sure the how self-aggregation time,self-aggregation temperature,copolymerization time,copolymerization temperature,H₂O feed,feed ratio,H₂SO₄ weight is effecting the molecule-weight with the ways of viscosity test and GPC.In the last,we determined every factor and produce a MQ silicon resin?Mn:4000,PDI:1.5,perfect tolune soluble?with several hydroxyl on it.MQ resin produced in the first chart and vinyl terminated agent are used as raw material to produce VMQ-1 silicon resin.Viscosity test and GPC are used to study the relationship between vinyl content and moleculweight.Vinyl titration and IR are used to study how catalyst,terminated agent,solvent are effecting vinyl content and hydroxyl change.The study shows that as H₂SO₄ grow,vinyl content grow first then decrease,when the H₂SO₄ is 1wt%,it has highest vinyl content.Vinyl content grow as terminated agent grow.Keep H₂SO₄ weight stable,decrease the solvent,we found that the vinyl content increase first,then decrease subsequently,it may be because the water in H₂SO₄ decrease and/ which leads the decrease.Use the hydroxyl on the MQ silicon resin as the functional grounp,react with trimethyl chlorosilane to produce a higher organ VMQ silicon resin.We choose three ways to operate the experiment,and we finally determine the trimethyl chlorosilane and water react with MQ has a best performance.The above-mentioned VMQ-1 and VMQ-2 were used to reinforce the rubber.The results show that the reinforcing effect of the platinum addition curing system is better than that of the peroxide curing system.When the resin dosage is 30wt%,the tensile strength of the silicone rubber is about 1.65 MPa,The tear strength was 2.8 kN / m,while the tensile strength of vulcanized rubber prepared by platinum was 3.6 MPa and the tear strength was 14 kN / m,and the change was obvious.The vinyl content of silicone resin is between 2.7% and 3.9%,and the effect of the change of vinyl content on the reinforcing effect is not obvious.With the increase of resin dosage,the mechanical properties of vulcanizate gradually increase.Considering the reinforcing effect and the processing technology,the dosage is 40wt%.The amount of curing agent was increased from 5,15,20,30 and 40 ppm.It was found that with the increase of the amount of curing agent,the curing rate was accelerated,and the mechanical properties increased slightly with the amount Decreased,but the elongation at which the elongation was gradually decreased,and finally the optimum amount was 20 ppm.?Si-H?/ n?Si-Vi?)was changed from 1,1.2,1.4,1.6.It was found that the mechanical properties increased first and then decreased,and finally the dosage?6.4 and 18mpa?and hydrogen content?0.38 and 0.75wt%?,and found that 6.4mpa and 0.75wt% of the reinforcement effect is better.The results showed that the reinforcement effect of VMQ-2 silicone resin and the silicone rubber were better than that of VMQ-1 silicone resin by comparing the reinforcement and transmittance of silicone resin with two kinds of resin.Based on the date,we finally determine a formula,38wt% VMQ-2 silicon resin weight,vinyl content 3.26wt% and we get a transparent silicon rubber with tensile strength 6.5MPa,enlongation at break 120%,tear strength 22 k N/m,and 92% transparency and 1g/cm3 density.