Vinylidene Fluoride-Based Polymer Network via Cross-Linking of Pendant Triethoxysilane Functionality for Potential Applications in Coatings

Vinylidene fluoride (VDF)-based copolymers bearing pendant trialkoxysilane groups for potential applications for coatings were synthesized via a free radical copolymerization of VDF with functional 2-trifluoromethyl acrylate cyclic carbonate monomer (MAF-cyCB), followed by introduction of silane pendant groups. MAF-cyCB was prepared from 2-trifluoromethacrylic acid with 70% overall yield. Radical copolymerization of VDF with MAF-cyCB initiated by tert-amyl peroxy-2-ethylhexanoate at varying VDF0/MAF-cyCB0 ratios led to several poly(VDF-co-MAF-cyCB) copolymers having different molar percentages of VDF (77–96%). The average molecular weights (Mns) reached up to 19 000 g mol–1 in fair to good yields (45–74%). Compositions and microstructures of all synthesized copolymers were achieved by 1H and 19F NMR spectroscopies. The resulting poly(VDF-co-MAF-cyCB) copolymers exhibited moderately high melting temperature (131–161 °C, with respect to the VDF content) while the degree of crystallinity, which reached up to 34%, decreased with increasing MAF-cyCB. Then, the pendant cyclic carbonate ester groups of the synthesized poly(VDF-co-MAF-cyCB) copolymers were quantitatively converted into novel triethoxysilane-functionalized PVDF, which could be further hydrolyzed under acidic conditions into trihydroxysilane-functionalized PVDF. Finally, steel plates were coated with the silylated PVDF and displayed improved adhesion properties compared to those of pristine PVDF.