Preparation, Modification And Application Of Silicone Elastomer Gel

Firstly, Silicone elastomer gel(SEG)was prepared through hydrosilylation withpolymethylhydrosiloxane(PMHS) as crosslinking agent, decamethylcycopentasiloxane (D5)as swelling agent and chloroplatinic acid as catalyst. For the purpose to obtain SEG with goodstability, single factor experiments and response surface analysis were made to optimized thereaction condition in which the reaction could get the highest reaction rate. In order toimprove the compatibility of SEG with other oil, alkyl was grafted onto SEG. Firstly,alkyl-modified PMHS(R-PMHS) was prepared by polymethylhydrosiloxane(PMHS) and1-dodecene through hydrosilylation, with chloroplatinic acid as catalyst. The optimal graftingconditions obtained through the single factor experiments, and then a series of R-PMHS andR-SEG with different alkyl grafting dosage and alkyl chain length were made in the optimalgrafting condition. Effect of alkyl grafting dosage and alkyl chain length on the compatibilityand swelling degree of R-SEG were discussed. Their structures were characterized by IR and1H-NMR. Reaction rate, grafting efficiency, performance of swelling degree, thermal cyclingstability, compatibility with oil were measured and tested.For the synthesis of SEG, the optimal condition is as follow:catalyst content is20.84ppm,reaction temperature is86.26℃, reaction time is47.87min, molar ratio of Si-H in PMHS toVinyl in Vi-PDMS is1.2. The optimal grafting condition for the synthesis of R-PMHS is asfollow: reaction temperature is100℃, reaction time is5h, the content of catalyst is2ppmof the mass of1-dodecene, the molar ratio is0.3. The R-SEG’s swelling degree increases withthe increase of alkyl grafting dosage. The compatibility of R-SEG increases with the increaseof alkyl grafting dosage and alkyl chain length.Secondly, SEG prepared in the optimal condition was applied to the formula of hairconditioner and moisturizing cream with two kinds of imported SEG and a domes tic SEGfrom the market. Combing test and silicone deposition test of the hair conditioner andmoisturizing properties of the cream were tested. Application performance of different SEGwas discussed through the analysis of the composition and structure of different SEG. Andthen, effects of alkyl grafting dosage and alkyl chain length of R-SEG on the combing of thehair conditioner, moisturizing properties and thermal cycling stability of moisturizing creamwere discussed.According to the test, with the alkyl grafted onto SEG, R-SEG has good compatibilitywith oil like GTCC, and is helpful for the thermal cycling stability of moisturizing cream. Theoptimal alkyl grafting dosage of R-SEG is29.32%and the optimal alkyl chain length is12.Finally, pilot trial of the synthesis of R-SEG was finished in the optimal condition, andproblems occurred during the trial were solved.