| Silicone resin, with the specific molecular structure, which has excellent weather resistance, heat resistance, electrical insulation, chemical resistance, flame resistance and hydrophobicity, is mainly used in the electronic element protection coatings, electronic components or integrated circuits bonded shell packaging materials and various insulating materials adhesive. Addition silicone resin does not contain solvents, and has the mildly curing conditions, as compared with condensation type silicone resin, it does not produce small molecule byproduct during the curing process, won’t result in bubbles, sand holes and a low shrinkage, has more extensive of applications. However, with the insufficients such as adhesive ability, low reactivity and high curing temperature of vinyl-addition silicone, making it is restricted in the applications. Therefore, the development of new additional silicone resin has important significance on silicone polymer industry. In this paper, on the basis of the research on vinyl silicone resin synthesis of our laboratory, designed and synthesized of an allyl addition silicone resin, and then comparative studied the hydrosilylation curing behavior, curing-product structure and performance of the allyl and vinyl silicone resins. The main works are as follows:1、With allyltriethoxysilane, vinyltriethoxysilane as raw materials, allyl and vinyl silicone resins were prepared by hydrolysis-condensation method. Their double bond content respectively0.895and0.926. Meanwhile the products were characterized by the means of F-TIR,1H NMR,29H NMR and XRD. According to the NMR spectra, the conversion rate and degree of condensation were calculated.2、The non-isothermal curing behavior of allyl silicone resin/phenyl hydrogen silicone oil(GR301B) and vinyl silicone resin/GR301B were comparative studied by DSC. The activation energy of those two systems were94.26kJ/mol and86.88kJ/mol by FWO method. The hydrosilylation curing kinetics of the two different systems were investigated by Malek method. The curing kinetic equations of them have been confirmed, through mold-fitting, the Sestak-Berggren(m,n) model was found to be appropriate to describe the cure kinetics of the studied silicone resin systems.3、The hydrosilylation reactivity were comparative studied with researching on the reaction rate constants, activation energy, entropy of activation of two silicone resin systems, meanwhile the influences of resin structure on the reactivity were studied. The results showed that allyl silicone resin has high reactivity, and it was verified by the infrared tracking and gel time method.4、The product structure of hydrosilylation were comparative studied with model compounds using, showed that due to the space steric effects, vinyl silicone mainly generated β-addition products (over90%), while allyl silicone only about74%.5、The effects of catalyst dosage on the two resin systems were studied, showed of allyl silicone has a higher reactivity even at5ppm catalyst content.6、The storage modulus and glass transition temperature were studied by DMTA for two curable resins, and crosslink density was calculated, researches showed that allyl silicone a slightly lower Tg than vinyl silicone with the lower cross-linking density.7、By using TGA, the thermostable performance and the activation energy of thermal degradation were studies, showed that allyl silicone resin still has good temperature resistance. |
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