Study On Preparation And Modification Of Novel Acrylate Polymer Latex And Its Application In Coatings

Acrylic latex is widely used in many fields such as chemistry,medicine,electronics and architecture because of its excellent properties of film-forming,good light resistance,low cost,easy synthetic process and so on.However,it has some drawbacks such as bad water resistance and stain resistance.In addition,it becomes sticky at the high temperature and fragile at low temperature situation.These disadvantages limit its further application.Presently,the study and modification of acrylic polymers with environmental protection,safety,economy and efficiency have been promoted by people's awareness of environmental protection and the formulation of relevant national standards.In this paper,the acrylic polymer latexes were mainly modified through emulsifiers and monomers to prepare novel acrylic latexes that have excellent properties and are more suitable for practical purposes.Furthermore,the resultant modified latex is used as the binder to prepare coatings and the properties of the coatings are studied.The contents and the related results in this study are as follows:(1)The modified acrylic polymer latex was prepared via semi-continuous seeded emulsion polymerization of methyl methacrylate(MMA),butyl acrylate(BA)as main monomers and hexafluorobutyl methacrylate(HFMA),benzyl methacrylate(BZMA)as functional monomers,which was initiated with potassium persulfate(KPS)and emulsified with the addition of mixed surfactants of anionic surfactant sodium dodecyl benzene sulfonate(SDBS)and nonionic surfactant octylphenol polyoxyethylene ether(OP-10).The structure of polymer latex was measured by Fourier transform infrared spectrometry(FTIR),differential scanning calorimetry(DSC)and thermogravimetry analysis(TGA).The latex film surface property was evaluated by contact angle and rate of water absorption.Results show that the acrylic polymer latex with good performance can be prepared successfully when the amounts of mixed emulsifiers are 4%;the mass ratio of SDBS to OP-10 is 1:2;the amount of KPS is 0.3%;the amounts of HFMA and BZMA are 6% and 2%,respectively.(2)The acrylic latex was prepared via semi-continuous seeded emulsion polymerization,which MMA and BA were main monomers,HFMA and BZMA were functional monomers and initiated with KPS and emulsified with the addition of mixed surfactants of anionic surfactant SDBS and ?-Cyclodextrins(?-CD).The relationship between the amount of surfactants and initiator,mass ratio of surfactants with monomer conversion rate are studied.Results show that the acrylic polymer latex has good stability when the amounts of mixed emulsifiers are 4%;the mass ratio of SDBS to ?-CD is 1:1;the amount of KPS is 0.7%.In addition,the water resistance and temperature resistance of latex film have been improved when the amounts of HFMA and BZMA are 2% and 5%,respectively.(3)The fluorinated crosslinked modified acrylic polymer latex was prepared by method of semi-continuous seeded emulsion polymerization when HFMA and hydroxy propyl methacrylate(HPMA)were used as the modified monomers and the anionic surfactant SDBS and ampholytic surfactant myristyl hydroxypropyl sulpho betaine(betaine)were used as emulsifiers.The preparing recipe and technological conditions were optimized and the resultant latex was characterized.Results show that the modified acrylic polymer latex has good overall properties when the amounts of mixed emulsifiers are 3%;the mass ratio of SDBS to betaine is 1:1;the amount of KPS is 0.6%;the amounts of HFMA and HPMA are 8% and 3%,respectively.(4)The acrylic emulsion was prepared via semi-continuous seeded emulsion polymerization with main monomers MMA,BA and modified monomer acrylic acid(AA)in water phase which was initiated with KPS and nonionic surfactant alkyl polyglycoside(APG)and anionic surfactant disodium laureth sulfosuccinate(AEMES)were used as emulsifiers.The preparing recipe and technological conditions were optimized and the resultant latex was characterized.Results indicate that the polymer latex has good stability and heat resistance when the amount of AA is 2%.(5)The crosslinked acrylic polymer latex was prepared by means of semi-continuous seeded emulsion polymerization when MMA and BA were used as main monomers and AA and N-Methylol acrylamide(N-MA)were used as the modified monomers.The mixture of AEMES and betaine was used as emulsifier and KPS was used as initiator.The preparing recipe and technological conditions were optimized and the resultant latex was characterized.Results show that polymer latex has excellent property when the amount of emulsifier is 5%,the amount of initiator is 0.7%,the amounts of modified monomers of AA and NMA are 4% and 2%,respectively.(6)The environmentally friendly waterborne coating was prepared when the acrylic polymer latex,which was prepared with environment-friendly emulsifiers of AEMES and APG,was used as the binder.The formula and process conditions of prepared coating were optimized and the properties of the coating were studied.