Preparation Of High Solid Content Silicone Microemulsion

Gemini surfactants have high surface activity,low Krafft point,and excellent solubility.In this paper,octamethylcyclotetrasiloxane?D₄? is used as the raw material,dodecylbenzenesulfonic acid?DBSA?is used as the catalyst,and Gemini type sodium dodecyldip Henyl ether disulfonate(C₁₂-MADS)is an emulsifier,and a stable hydroxypolysiloxane microemulsion with a solid content of 50% was prepared by emulsion polymerization.Based on the ring opening of D₄,-NH₂ and vinyl groups were introduced to prepare three types of high-solid-content polysilane microemulsions.?1?Preparation of high solid content hydroxypolysiloxane microemulsionIn this thesis,the effect of sodium lauryl emulsifier sodium dodecylbenzenesulfonate and Gemini emulsifier sodium dodecyl dip Henyl ether disulfonate on polysiloxane microemulsion was first studied.Gemini-type emulsifier prepared microemulsion monomer conversion rate and reaction rate is higher,so choose Gemini-type emulsifier.On this basis,the effects of the amount of catalyst,the amount of Gemini-type emulsifier,and the polyol on the polymerization kinetics,particle size,and particle size distribution were studied.When the amount of C₁₂-MADS is 5% to 6%,the amount of catalyst is 10%,and the amount of ethylene glycol is 3%,a high solid content hydroxy milk was successfully prepared with a small particle size,uniform distribution,and good stability.?2?Preparation of high solid content amino modified microemulsionBased on the preparation of high solid content hydroxypolysiloxane microemulsion,the coupling agent N-cyclohexyl-?-aminopropylmethyldimethoxysilane?KH-104?,N-??-aminoethyl Group?-?-aminopropyltriethoxysilane?KH-791?,which modified the microemulsion.As a result,it was found that as the coupling agent was added for a longer period of time,the stability of the microemulsion increased,and the particle size of the emulsion became smaller.As the amount of the coupling agent increased,the particle size of the emulsion gradually increased and the stability decreased.Comprehensively considered when the coupling agent KH-104 was added at an interval of 2 to 3 h and the dosage was between 0.5% and 2%,when the coupling agent KH-791 was added at an interval of 3 h and the dosage was 0.5% to 1%,the prepared Amino modified microemulsion has better performance.?3?Preparation of high solid content vinyl-amino copolymer modified microemulsionTetramethyltetravinylcyclotetrasiloxane(D₄^Vi) comonomer was added on the basis of preparing hydroxy microemulsion.When the monomer ratio is D₄:D₄^Vi=4:1 and the reaction time is 8 h,a stable copolymerized microemulsion is prepared.Under this condition,amino modification was performed.When the coupling agent KH-104 was added for 2 hours and the dosage was 0.5% to 2%,the coupling agent KH-791 was added for 3 hours and the dosage was 0.5 to 1%.The performance of the prepared vinyl-amino copolymer modified microemulsion is better.