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

摘要

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, C_(11) H8O2F_(12)) 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, C_(12)H_(25)Si(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.