| Most of the heat-resistant and anti-corrosive coatings were solvent-based, which needed to evaporate organic solvent into the environmentduring the process of production and application. In this case, thesecoatings not only had caused serious pollution, but also had made a greatwaste of resources. Developing waterborne coatings was one of theeffective measures to solve the aforesaid problem. At present,styrene-acrylate emulsion was the most widely used film former inwaterborne coatings, which had excellent mechanical properties and goodfilm forming ability with great cost advantage. Whereas, it even couldn’tbe used in mild anti-corrosion area because of the poor anti-water,anti-reagent and heat-resistant properties.In order to improve the heat-resistant and anti-corrosive propertiesof styrene-acrylate emulsion, a steady organosilicone fluorinated styrene-acrylate micro-emulsion was synthesized by graft copolymerizaion ofmethyl methacrylate (MMA), butyl acrylate (BA), styrene (St), acrylic acid (AA), triethoxyvinylsilane (VTES) and dodecafluoroheptyl Metha-crylate (G04);By adjusting the proportion and amount of the monomers,emulsifiers and initiator, the effect of these factors on the emulsion filmwas studied; Using posted-crosslinking method and adding the self-condensation inhibitor, the effect of VTES self-condensation wasreduced; The effect of VTES and G04amount on water absorption,attachment strength, high temperature performance and anti-corrosionperformances of the modified emulsion film was studied. Based on theresults of the experiments, by semi-continuous emulsion polymerizationprocess, when the amount of initiator was0.4%, the total amount of SDSand OP-10used as the proportion of1:2was2.2%, the amount of VTESand G04were5%and18%of the total co-monomers amount respectively,the water absorption of the micro-emulsion film reduced to5%, and thefilm had excellent mechanical and anti-corrosion properties. Besides, themodified emulsion film could perform well without stickiness and bubbleunder120℃.The organosilicone fluorinated styrene-acrylate micro-emulsion wastested and characterized by a number of modern analytical and testingmethods. The FI-IR spectral graph showed that VTES and G04hadalready graft copolymerized into the copolymer successfully; The contactangle test showed that the contact angle of water on micro-emulsion filmwas increased by graft G04;The TG test showed that the modified styrene-acrylate micro-emulsion had much better heat-resistant propertythan the traditional styrene-acrylate emulsion.The TEM image andparticle size test showed that the particles in the organosiliconefluorinated styrene-acrylate emulsion was75.1nm, which meant amicro-emulasion had been synthesized successfully by the optimizingprocess in this thesis. |
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