Macromolecules, Vol.50, No.23, 9329-9339, 2017
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 [VDF](0)/[MAF-cyCB](0) ratios led to several poly(VDF-co-MAF-cyCB) copolymers having different molar percentages of VDF (77-96%). The average molecular weights (M(n)s) 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 H-1 and F-19 NMR spectroscopies. The resulting poly(VDF-co-MAF-cyCB) copolymers exhibited moderately high melting temperature (131-161 degrees 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.