Abstract
The use of [Mn(R F)(CO) 5 ] (R F = CF 3 , CHF 2 , CH 2 CF 3, COCF 2 CH 3) to initiate the radical polymerization of vinylidene fluoride (F 2 C=CH 2 , VDF) and the radical alternating copolymerization of vinyl acetate (CH 2 =CHOOCCH 3 , VAc) with tert-butyl 2-(trifluoromethyl)acrylate (MAF-TBE) by generating primary R F • radicals is presented. Three different initiating methods with [Mn(CF 3)(CO) 5 ] (thermal at ca. 100 • C, visible light and UV irradiations) are described and compared. Fair (60%) to satisfactory (74%) polyvinylidene fluoride (PVDF) yields were obtained from the visible light and UV activations, respectively. Molar masses of PVDF reaching 53,000 g·mol −1 were produced from the visible light initiation after 4 h. However, the use of [Mn(CHF 2)(CO) 5 ] and [Mn(CH 2 CF 3)(CO) 5 ] as radical initiators produced PVDF in a very low yield (0 to 7%) by both thermal and photochemical initiations, while [Mn(COCF 2 CH 3)(CO) 5 ] led to the formation of PVDF in a moderate yield (7% to 23%). Nevertheless, complexes [Mn(CH 2 CF 3)(CO) 5 ] and [Mn(COCHF 2)(CO) 5 ] efficiently initiated the alternating VAc/MAF-TBE copolymerization. All synthesized polymers were characterized by 1 H and 19 F NMR spectroscopy, which proves the formation of the expected PVDF or poly(VAc-alt-MAF-TBE) and showing the chaining defects and the end-groups in the case of PVDF. The kinetics of VDF homopolymerization showed a linear ln[M] 0 /[M] versus time relationship, but a decrease of molar masses vs. VDF conversion was noted in all cases, which shows the absence of control. These PVDFs were rather thermally stable in air (up to 410 • C), especially for those having the highest molar masses. The melting points ranged from 164 to 175 • C while the degree of crystallinity varied from 44% to 53%.