Study On The Effect Of Emulsification System On Synthesis And Properties Of Acrylic Emulsion

Waterborne coatings have some advantages ofenvironment-friendly,energy saving property and safety. It is an inevitabletrend of environmental protection. With the change of life quality, people paymore attention to the advantages of waterborne coatings.Waterborne coatingsfor woodenware are one of research hotspots. Waterborne acrylate coatingswith excellent properties have great practical value and application prospect.In this thesis, detailed research has been done on the synthesis of acrylicemulsion, detailed screening of existing acrylic emulsion formula has beendone separately using anionic emulsification system and cationicemulsification system.Characterization and comparison of anionic acrylicemulsion and cationic acrylic emulsion also have been done. The mainresearch works and results are as follows:1. Systematic research of composite emulsifier system which containsreactive emulsifier A and anionic emulsifier B has been done. Ensuringpolymerization stability of emulsion, some discussion of influencing factors ofparticle size has been done.The influencing factors include seed amount, stirring speed, the amount of emulsifier, the ratio of emulsifiers, theproportion of soft/hard monomer etc.An anionic acrylic emulsion which isless than80nm has been obtained.2. Adding nonionic emulsifier P in original emulsion, we found that afterintensive stirring,the foam is less than the original emulsion.Thedisappearance rate is high than the original emulsion.The result show that Phas low-foaming property in this system.When adding1%of totalmonomers,the low-foaming property is best.3. Research has been made of synthesis of cationic acrylicemulsion,stable cationic acrylic emulsion has been obtained. The effect ofsolid content, polymerization process, pH value, addition methods ofinitiator,the ratio of emulsifiers, protective colloid has been researched.Theresults showed that the emulsion with optimum stability was made by seedpre-emulsification polymerization, using cationic emulsifier (C) and nonionicemulsifier P or T, the optimum amount of protective colloid is1%of totalmonomers.The optimum pH value is5.4. In order to improve mechanical stability of cationic emulsion,Wesynthesized two kinds of unsaturated quaternary ammonium salt,(AB) and(DB).The effect of unsaturated quaternary ammonium salt on stability ofcationic emulsion has been studied. The results suggested that the emulsionwith optimum stability was made by seed pre-emulsification polymerizationwith initiator (Y3) and initiator (Y4) compound initiator system.The optimum amount was0.1%of the total monomers both for Y3and Y4, and the optimumamount of AB was2%. While adding2%-3%of the total monomers, asoap-free cationic emulsion with35%solid content has obtained.