The Study Of Room Temperature Self-crosslinkable Polyacrylate Emulsion With Multiple Crosslinking System

Polyacrylate emulsion has excellent properties such as water resistance,weatherability and aging resistance,and it'sraw materials ischeap,so it is widely used.However,the traditional macromolecular of pure acrylic emulsion polymer is mainly linearr,the adhesion,solvent resistance and other properties ofthe filmsare poor.Short pot life cross-linkable two-component system and high curing temperatureof latent curing system limits their scope of application.In view of these problems,a room temperature self-crosslinkable polyacrylate emulsion with multiple crosslinking systemwas developed to improve the performance of emulsionfilm.In this paper,semi-continuous seed emulsion polymerization was used to prepare the polyacrylate emulsion.The influences of the adding method of seed pre-emulsion and shell pre-emulsion,the amount of initiator and compound emulsifier were studied.The particle size of a translucent blue emulsion was 89.37 nm and it's PDI index of 0.068 was prepared with 3wt% compound emulsifier of SDS:OP-10(3:5),0.3wt% initiator,3h adding tinme of the shell pre-emulsion.N-MA / GMA / Organic siloxane B / MAA multiple cross-linking system was obtained by modified the acrylate emulsion with MAA,NMA,GMA and Organic siloxane B.In this study,the influences of the amount of MAA,NMA,GMA,external crosslinking agent,Organic siloxane B and it's adding order of emulsion and the film were studied.The milk blue light emulsion of 1.8wt% gelation stability satable for four months at room temperature was prepared with MAA 2wt%,GMA 6wt%,organic siloxane B 3wt% and it's adding order 80:20,aziridine 3wt%.When the emulsion was diluted to a 20wt% by using a 3: 1 mixture of ethanol and water,the surface drying time of the film was 24 s at 65 ?.After 10 days room temperature curing,the hardness of the emulsion film was H,the adhesive force was 0 grade,the film could be scrubbed 61 times with 70wt% ethanol aqueous solution.TGA analysis shows that the film modified by external crosslinking agent had a higher decomposition temperature,this is because that emulsion occurred reation external crosslinking agent.The results of DSC analysis shows that the pure acrylic emulsion has two glass transition temperatures of 23 ° C and 83.2 ° C,the polyacrylate emulsion modified with MAA,N-MA and GMA has two glass transition temperatures of 32.6°C and 78.1°C,the polyacrylate emulsion modified with MAA,N-MA,GMA and B has three glass transition temperatures of 23.4 ° C,46.5°C and 78.4°C,this indicate that the emulsion synthesized has obvious phase separation,the emulsion may have a core-shell structure.The results of IR and NMR show that MMA,BA and four modified monomersare all polymerized into the copolymer,they forme a multi-crosslinking system.