| Acrylate latex is a kind of environmental friendly latex which can be easily prepared. In order to obtain the latex with better overall performances to meet the need of production, more and more researches focusing on modification of acrylate latex were conducted, among which modification by functional monomers and organic-inorganic composite are common ways and widely applied. In this thesis, a series of acrylate latexes with preferable properties were prepared via semi-continuous pre-emulsification emulsion polymerization, with ammonium persulfate (APS) as initiator, methyl methacrylate (MMA) and butyl acrylate (BA) as main monomers, and acrylic acid (AA) as carboxyl functional monomer. The effects of ammonium sulfate allyloxy nonylphenoxy poly (ethyleneoxy)(10) ether (DNS-86), sulfo succinate decyl poly (ethyleneoxy)(6) ether ester disodium (DNS-628), sodium dodecyl sulfate (SDS) as emulsifiers and dibutyl itaconate (DBI) and dibutyl maleate (DBM) as functional monomers as well as the compound modification of silica sol and silane coupling agent y-methacryloxypropyltrimethoxysilane (KH-570) on the performance of acrylate latexes and films were discussed.This thesis consists of four parts:Part One, the influence of emulsifier types and dosage on the performance of latexes. A series of acrylate latexes were prepared using DNS-86, DNS-628and SDS as emulsifiers, respectively. Test results showed that the overall performances of latexes were good when adopting DNS-86as emulsifier with a dosage of2%.Part Two:the influence of DBI and DBM on the performance of acrylate latexes. Results demonstrated that the introduction of DBI or DBM could keep latexes with high conversion and good polymerization stability, and the elongation at break and water resistance of latex films enhanced, which showed DBI and DBM played an internal plasticization role. Moreover, the addition of functional monomer reduced alkali resistance and thermostability of films slightly. Comprehensive comparison showed that latexes prepared using3.5%of DBI had good performance.Part Three:the investigation of influence of inorganic component silica sol on the properties of acrylate latexes. Results showed that the acrylate/silica composite latexes exhibited excellent stability in spite of the variation of amount of silica sol.The particle size decreased with the increasing of amount of silica sol. The composite latexes showed characteristic of pseudoplastic fluid, the viscosity of latexes increased with the increasing of silica sol amount. With the increasing of the dosage of silica sol, the roughness, toughness, alkali resistance, solvent resistance and tensile strength of latex films increased while the water resistance decreased and the elongation at break of films was greater than that of blank sample. Results demonstrated that latexes prepared with15%of silica sol had good performance.Part Four:the effect of silane coupling agent KH-570on performance of acrylate/silica composite latexes. Tests indicated that the overall performance of latexes was good when the KH-570amount was less than2%. The particle size increased with the increasing of the amount of KH-570. EM results showed that some SiO2nanoparticles were distributed around the latex particles with some embedded inside the latex particles. The KH-570modified acrylate/silica composite latexes showed characteristic of pseudoplastic fluid. The latex films preserved excellent adhesiveness, flexibility, impact resistance, gloss and thermostability after the introducing of KH-570. |
