| Emulsion synthetic technology develops rapidly today， some of the emulsionand the associated paint products were widely applied to many aspects in our life,which needs the emulsion product with high performance. The acrylate emulsion, withgood film-forming properties and good adhesion properties, is one of the researchbranches in the emulsion fields. However, the performance became worse at high orlow temperature environments; and the water resistance and stain resistance weredeteriorated. So, to develop new acrylic emulsion is an important research direction inthe field of emulsion.In this paper, the fluorine and silicon elements were introduced into thepolymerization process using water as the dispersion medium, which can reduceenvironmental pollution. And, a new type of acrylic emulsion was designed andsynthesized at the same time. The innovation of this article is the introduction of nano-SiO2and FM during the polymerization process. The acrylate emulsion modified withfluoro and silicone compounds was prepared by the following steps: firstly, nano-SiO2was ultrasonic dispersed in ethanol as a co-solvent; then silane coupling agent(KH570)was selected as a modifier for the surface modification of nano-SiO2. The soap-freeemulsion was prepared using several monomers, including butyl acrylate (BA), methylmethacrylate methyl ester (MMA), methacryloyloxyethyl trimethyl ammoniumchloride (DMC) and perfluoroalkyl acrylate (FM) using azobisisobutyronitrile (AIBN)as oil-soluble initiator, AIBA as water-soluble initiator, and hydroxyethyl acrylate (HEA) as crosslinker.Single-factor methods were used to select the ratio of raw materials, theconditions of reaction, to get the final modified emulsion with good stability andperformance. he structure and properties of modified emulsion and coating were testedby fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA)and derivative thermo gravimetric analysis (DTG), differential scanning calorimetry(DSC), X-ray diffraction analysis (XRD), contact angle measuring instrument, laserparticle size analyzer (DLS), scanning electron microscopy (SEM) and conecalorimeter, et al.The analysis and test results were showed as follows:The reasonable reaction conditions of modified emulsion: reaction temperaturewas80℃; the copolymerization reaction time was7h; the ratio of nano-SiO2andethanol was1:100; the amount of KH570was1.97%of the total monomers’s mass; theratio of other monomers was m (BA): m (MMA): m (FM): m (DMC): m (HEA) was15.76:31.04:29.56:20.69:0.49; the optimum amounts of AIBN and AIBA was0.69%of the total monomers’s mass; and DMF was added with an same amount of the totalamount of monomers.When the addition of FM and Nano-SiO2was0.49%and29.56%, the modifiedemulsion and its latex film can achieve good performance. The performance modifiedemulsion were as follows: the latex was uniform and stability; the emulsion wastranslucent, pH was7.2~7.7; particle size distribution test showed that index ofpolydispersity was0.132; and the average particle diameter of the latex particles was148.7nm; the storage stability could keep for more than100days at the condition ofroom temperature; the water absorption of latex film was8%; pencil hardness was2H,adhesion was grade one; contact angle of water was116°; the film has good resistanceof water and other solvents. |
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