Preparation And Characterization Of Side Chain Hydroxypropyl Polysiloxane

Polysiloxane has the advantages of good thermal stability,superior dielectric,temperature durability and biocompatibility,which is irreplaceable by many other materials.Polysiloxane with hydroxyalkyl has very extensive application value in organic silicone modification,health care,skin and hair care products,coatings,electronic and electrical industries,mold processing,flame retardant materials and so on.And many researchers pay attention to it.At present,the main methods for preparing hydroxyalkyl polysiloxane are organometallic synthesis arid hydrosilylation,but the former is not suitable for industrial production because of high operation requirement.Hydroxyl protection with special reagent is needed in the latter,however,which makes the reaction step tedious.Therefore,it is of great theoretical significance and practical value to explore a new method of efficient synthesis of hydroxyalkyl polysiloxane,especially the new method for the preparation of side chain hydroxyalkyl polysiloxane.Therefore,this paper explores two new methods for the preparation of side chain hydroxypropyl polysiloxane,which is simple to operate and does not need additional special reagents to protect hydroxyl groups.First,bis(allyloxy)-methylsilane was prepared by alcoholysis reaction only using allyl alcohol and methyldichlorosilane as starting reactants.Then,the hyperbranched polycarbosiloxane was synthesized by hydrosilylation reaction from the monomer itself.Finally,the side chain hydroxypropyl polysilicon was prepared through acid hydrolysis or co hydrolysis with other monomers.Simultaneously,we explored the effects of different reaction conditions on the alcoholysis reaction,hydrosilylation reaction and hydrolysis reaction.On the basis of the synthesis of hyperbranched polymers,various effects including-catalyst dosage,solvent dosage,the mode of feeding,reaction time,reaction temperature and co-catalyst type on regioselective hydrosilation were further explored.Second,allyloxymethylchlorosilane was synthesized from methyl-dichlorosilane and allyl alcohol at the same molar ratio.And then the linear polysiloxane,which was made after hydrosilylation,were hydrolyzed under condition of acid,obtaining the side chain hydroxypr,opyl polysiloxane.The experiment not only verified the feasibility of the one pot method to prepare the side chain hydroxypropyl polysiloxane,but also increased the selectivity of the γaddition product to 50%in the hydrosilation reaction.The alcoholysis-hydrosilylation-hydrolysis method is simple and safe,and the raw material is economically easy to obtain.The reaction steps are simple and easy to industrialize.