Synthesis, modification and characterization of core–shell fluoroacrylate copolymer latexes

Core–shell fluoroacrylate copolymer latex, typically used for the protection of ancient stone monument, was synthesized in this paper by semi-continuous seed emulsion polymerization with butyl acrylate (BA) served as the core, methyl methacrylate (MMA), BA and dodecafluoroheptyl methacrylate (DFHMA, C11H8O2F12) served as the shell. At the same time, the above core–shell fluoroacrylate latex was modified by hydrolysis of tetraethyl orthosilicate (TEOS, Si(OC2H5)4) in the presence of silane coupling agent dodecyltrimethoxysilane (DTMS, C12H25Si(OCH3)3). The chemical component of the final latex was analyzed by FT-IR. Morphology structure and the particle size of core–shell latex were determined by TEM. The effect of DFHMA and TEOS content on the latex and film properties was characterized by SEM-EDX, AFM, TEM, DSC and UV–vis. The analysis results indicated that the copolymer latex particle presented uniform sphere core–shell structure with 40–50 nm in diameter. About 30 wt% DFHMA gave favorable characteristics both in latex and in film properties. Compared with core–shell fluoroacrylate latex, the modified fluoroacrylate copolymer displayed, when TEOS was controlled in 2.2–3.8 wt%, sound performances in hydrophobic, mechanics, thermodynamics and resistance to ultraviolet.

Graphical abstractTwo fluoroacrylate latexes with core–shell structure were synthesized in this paper by semi-continuous seed emulsion polymerization. One latex was the random copolymer prepared by butyl acrylate (BA), methyl methylacrylate (MMA) and dodecafluoroheptyl methacrylate (DFHMA). The other latex was silica-containing fluoroacrylate copolymer prepared by the modification of above BA/MMA/DFHMA core–shell copolymer with the hydrolysis of tetraethyl orthosilicate (TEOS, Si(OC2H5)4) in the presence of dodecyltrimethoxysilane (DTMS, C12H25Si(OCH3)3). The latexes were characterized by FT-IR, SEM-EDX, DSC, TEM and AFM. Figure optionsDownload full-size imageDownload as PowerPoint slide