Preparation And Properties Of Silicone Terminated Polyethers Ealants

Sealant is a kind of material used to bond solid or different kinds of solid materials.The most commonly used sealants,including silicone sealant,silicone sealant and polyurethane sealant,are becoming more and more widely used in industrial and civil fields such as houses,bridges,cars,ships and electronic communications.Polyether polyether sealant is a polyether polyol modified silicone sealant through silane coupling agent.This sealant has the advantages of polyurethane sealant and silicone sealant without their shortcomings,and has good practical value.Based on the principle of Williamson etherification,polyether polyols were grafted onto the ends of polyether polyols by using halogenated silane coupling agent.The optimum conditions for the salinization of polyether polyol alcohol,the influencing factors of the sealing end rate of silane are studied.The performance and curing conditions of the silane sealing polyether sealant are roughly explored and a set of better formula is prepared.In the study of polyether polyol alcoholization,the following conclusions are drawn:From the hydroxyl conversion rate of polyether polyols,sodium methoxide is more suitable for alcoholization and reagents than alkali hydroxide such as sodium hydroxide and potassium hydroxide.The best technological conditions of using sodium methoxide as alcoholization reagent are as follows:the reaction temperature is 110 degrees,the reaction time is 1.5 hours,and the material ratio is 1.1 to 1.The conversion rate of hydroxyl group of polyether polyols with molecular weight of 2000 can reach 75%.The following conclusions can be drawn in the study of silylation reaction of polyether polyols:When the reaction temperature is 70 degrees,when the material ratio is 1.4 to 1,the reaction time is 4 hours,and the sealing rate of polycther polyols with molecular weight of 2000 is about 74%.After purification of the sample,it can be proved by IR,1H NMR and 13C NMR that silane coupling agent is grafted on the ends of polyether polyols and the molecular weight was determined by GPC.The sealant with the following formula is applied to the wood plate of 30mm × 40mm,and the shear force is about 700N,and the curing speed is fast.The dry time is only ten minutes.The formula is as follows:the silane terminated polyether of 2000 molecular weight is 100g,the surface activated calcium carbonate is 160g,the binding promoter is 30g,the curing agent is 2g,and the plasticizer 20 g.In this paper,a new synthetic method of silane sealing polyether sealant is studied.It is not necessary to use platinum and other precious metals as catalysts to reduce the cost of production and avoid environmental pollution.This kind of sealant has excellent construction convenience and can be widely used in automobile manufacturing,building engineering and so on.It has a broad market prospect and important practical significance.