Preparation And Properties Of Acrylic Emulsion And Coating Modified By Organic Silicon,Organic Fluorine And Epoxy Resin

The increasing of environmental pollution and the frequent occurrence of various human diseases make people pay more attention to environmental protection and health issues,and it's an urgent matter to advocate environment-friendly coating.As an important environment-friendly coating,waterborne coating is gradually taking place of solvent coating for it not only has low content of Volatile Organic Compounds?VOC?but also has the advantage of green environment protection,safe and harmless,saving resource and energy.Waterborne acrylic coating,which maintains the good performance of solvent acrylic coating and meets the requirements of safety and environment protection,has a very broad development prospect.However,acrylic film has some shortcoming,such as hot-sticky,cold-soluble,poor water resistance,poor alkali resistance and weatherability,and its wide application has been restricted,so the modification of acylic has become a hot spot of research.In this paper,a waterborne epoxy-acrylic emulsion containing silicon and fluorine?FSiWEA?was synthesized by using E-44 type epoxy resin,?-methacryloxypropyl trimethoxy silane?MPS?and dodecafluoroheptyl methacrylate?DFMA?as modifier and SiO₂/FSiWEA hybrid film was successfully obtained by dipping the slide glass into the mixture of FSiWEA and micro-nano SiO₂ composite particle.The main contents are as follows.The waterborne epoxy-acrylic emulsion?WEA?was prepared by emulsion polymerization and the influence of the content of each reactants on the properties of emulsion or film was also studied.The results showed that the WEA emulsion and its film had the best performance when the dosage of APS was 0.8%of the total monomer,the dosage of emulsifier was 3.5%,the dosage of NaHCO₃ was 0.55%,the dosage of MAA was 3%,and the dosage of E-44 was 10%.On the basis of the above formula,successively introduced MPS and DFMA,the FSiWEA emulsion was synthesized by pre-emulsification seed emulsion polymerization and the effect the content of MPS and DFMA on the properties of emulsion and film was also studied.It was found that the FSiWEA emulsion and film had good properties when when the dosage of MPS was 5%of the total monomer and DFMA was 10%.The solid content of the emulsion was 33.73%,the monomer conversion was 98.33%,the gel rate was 0.39%,and the emulsion stability passed the test.The average particle size of the latex particle was about 115nm,the water absorption of the film was 9.49%,and the film had good water resistance,acid resistance,alkali resistance and salt resistance.The hardness and adhesion of the film reached 3H and 1 grade,respectively,and the water contact angle of the film increased to 74°,but it was still hydrophilic.The surfacial-amino modified micro-nano SiO₂ composite particles were obtained by APTES modification on different sizes of SiO₂ synthesized through sol-gel method and SiO₂/FSiWEA hybrid film was successfully obtained by dipping the slide glass into the uniform mixture of FSiWEA emulsion and micro-nano SiO₂composite particle.It turned out that when the ratio of micro-nano SiO₂ composite particles to the polymer content in the FSiWEA emulsion was 1:1,the film performance was the best and its water contact angle reached 149°,which was close to superhydrophobic.The content of micro-nano SiO₂ composite particles continued to increase,while the water contact angle of the film increased,but its performance became worse.