Study And Preparation On Copolymerization Behavior Of Vinyl Tertiary Carbonate-acrylic Emulsion

With the development of society and the improvement of people's living standards,people's demands for environmental protection are increasing day by day.The green water-borne industrial paint has been developed rapidly.In view of the poor water resistance,high temperature resistance and ultraviolet radiation resistance of vinegar emulsion and styrene acrylic emulsion,Tertiary vinyl carbonate monomers with tertiary carbon structure,large steric hindrance and good tolerance were polymerized to further improve the properties of the emulsion.The prospect of application is very broad.In this paper,methyl methacrylate(MMA),butyl acrylate(BA)and VV-10 were used as the main monomers,ammonium persulfate(APS)as an initiator,nonionic emulsifier and anionic emulsifier as the complex emulsifiers.The seed emulsion polymerization method was used to synthesize vinyl tertiary carbonate-acrylic emulsion on the basis of free radical copolymerization.By means of nuclear magnetic resonance(~1H-NMR)characterization,FR method was used to calculate the copolymerization reactivity ratio of MMA/BA/VV-10 ternary copolymers at low conversion,and the copolymerization activity of MMA/BA/VV-10 was higher than that of VV-10,and it was not ideal copolymerization.The structure and properties of the synthesized emulsion were characterized by means of infrared spectroscopy(FT-IR),laser particle size analyzer,thermogravimetric analysis(TGA)and differential scanning calorimetry(DSC).The results showed that the synthesis process of synthetic emulsion was more difficult than that of pure acrylic emulsion,and FT-IR analysis showed that all the monomers were completely reactive.With the increase of total emulsifier,the particle size decreased,and the appearance of the blue phase of the emulsion deepened,but the water absorption rate of the coating gradually increased.Thermogravimetric analysis(TGA)showed that adding 10%of vinyl tertiary carbonate monomer on the basis of pure acrylic emulsion increased its heat resistance relatively from290.7?to 310.3?.Differential scanning calorimetry(DSC)was used to determine the size of the emulsion and pure acrylic emulsion synthesized by ourselves.The glass transition temperature can reach about 50?.Under the same conditions of emulsifier dosage and proportion,with the increase of the monomer content of vinyl tertiary carbonate(less than 20%of the total monomer),the water absorption of the film decreased,the particle size of the emulsion increased.With the same amount of emulsifier,proportion and content of vinyl tertiary carbonate,the content of diacetone acrylamide(DAAM)and adipic hydrazine(ADH)was increased(less than 2.5%of the total monomer),the water absorption of the film decreased,the viscosity increased,and the contact angle increased.The structure and properties of the MMA/BA/MAA-VV-9/VV-10/MAA core shell emulsion were characterized by means of FT-IR,laser particle size analyzer,transmission electron microscope(TEM)and TGA.The results showed that the core structure MMA/BA/MAA emulsion with VV-9/VV-10/MAA as the shell was successfully synthesized.With the increase of emulsifier dosage,the particle size of the core layer and shell particles gradually decreased.The appearance of the blue phase of the emulsion increased,the stability increased and the viscosity increased.However,the water absorption of the coating increased gradually,and the contact angle decreased.Under the condition of certain amount of emulsifier,with the increase of phosphate emulsifier 10P,the particle size of core layer increased gradually,the particle size of shell layer decreased gradually and then increased again.The reaction system was gradually stable,and the water absorption of the coating film was almost unchanged.Under the same conditions of emulsifier dosage and proportion,with the increase of the content of vinyl tertiary carbonate monomer(more than 50%of the total monomer),the water absorption of the film decreased,and then increased;the particle size of the emulsion increased,the viscosity increased.With the same amount of emulsifier,ratio and content of vinyl tertiary carbonate,the water absorption of the film decreased with the increase of DAAM and ADH(less than 2.5%of the total monomer).TGA showed that the thermal decomposition temperature of MMA/BA/MAA-VV-9/VV-10/MAA core shell emulsion was around300?.