Radical copolymerization of vinylidene cyanide with 2,2,2‐trifluoroethyl methacrylate: Structure and characterization

Abstract

A novel copolymer of vinylidene cyanide (VCN) and 2,2,2-trifluoroethyl methacrylate (MATRIF) was synthesized by bulk free radical process in a 52% yield from an equimolar comonomer feed. The copolymer's composition and microstructure were analyzed by FTIR, 1 H-and 13 C-NMR spectroscopy, SEC, and elemental analysis. The reactivity ratios calculated from both the Q-e Alfrey-Price parameters and the Jenkins' Patterns Scheme indicate a tendency to alternation in the copolymerization, the latter method suggesting that MATRIF homopropagation be slightly favoured (rThe molar incorporation of VCN in the copolymer was only 42 mol % according to the 9.0 wt % nitrogen content determined by elemental analysis, in good agreement with the value obtained by 1 H-NMR. High-resolution 1 H and 13 C-NMR spectra were used to study the microstructure of the copolymer. As an example, the three well-resolved carbonyl resonances in the 13 C-NMR spectrum were assigned to the MATRIF-centered triads VMV, VMM, and MMM, respectively, (V and M stand for VCN and MATRIF, respectively). The presence of VCN dyads (e.g., in VVM and VVV sequences) was shown to be marginal or absent altogether. Thermogravimetric analysis of poly(VCN-co-MATRIF) copolymer showed good thermal stability, and its main pyrolytic degradation taking place only above 368 C. A 4% weight loss at about 222 C suggested the presence of a few VCN homodyads, possibly inducing thermal depolymerization. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: [4900][4901][4902][4903][4904][4905][4906][4907][4908] 2010

Thermal degradation behaviour of a nearly alternating copolymer of vinylidene cyanide with 2,2,2-trifluoroethyl methacrylate

“…The two monomers, VCN and MATRIF, were identified as the main volatile pyrolytic products, similarly to the case of VCN copolymers with methyl a-acetoxyacrylate [23] or para-halogenated styrenes [24], and of methylvinylidene cyanide copolymers with substituted styrenes [27]. The presence of weaker signals belonging to the alternating dimer and to the trimers from both alternating (MATRIF-VCN-MATRIF) and non-alternating sequences (VCN-MATRIF-MATRIF) without any peak assigned to dimers or trimers containing two VCN units confirms the copolymer structure discussed elsewhere [14], in which the VCN units are generally isolated between two MATRIF co-units. The lowtemperature degradation may therefore be associated with a small fraction of less stable oligomers, in which the presence of a not negligible fraction of VCN dyads may account for both the observed strong UV absorption of the small oligomeric fraction from the SEC analysis (e.g., from unsaturated chain end conjugation with nitrile) and the lower thermal stability.…”

“…The copolymer of VCN and MATRIF, poly(VCN-co-MATRIF), was synthesized by free radical copolymerization in bulk, and its structure characterized as reported previously [14]. A MATRIF homopolymer was prepared by polymerization in dioxane using azobis-isobutyronitrile (AIBN, 1 wt.%) as the free radical initiator (M n ¼ 19; 000, M w =M n ¼ 2:3).…”

“…The presence of unstable homo-VCN dyads (small but not negligible, as discussed elsewhere [14]) capable of generating volatile fragments by pyrolytic decomposition of VCN-rich copolymer chain ends or oligomers, was also considered as the possible cause of the low-temperature weight loss. Indeed, SEC analysis confirmed the presence of a small oligomeric fraction absorbing strongly in the UV range.…”

“…In a previous paper the results of an investigation on the radical copolymerization of VCN and 2,2,2-trifluoroethyl methacrylate (MATRIF) focused on the characterization of the resulting copolymer composition and microstructure have been presented [14]. This, and similar copolymers based on the combination of cyanomonomers with side-chain fluorinated comonomers [5,15] are of interest for the development of new dielectric materials.…”

Novel Copolymers of Difluoro Ring-substituted 2-Phenyl-1,1-dicyanoethylenes with 4-Fluorostyrene: Synthesis, Structure and Dielectric Study

“…The synthesis of TSE copolymer based on methyl vinylidene cyanide and 2,2,2-trifluoroethyl methacrylate has been reported (19) and recently its dielectric behavior has been investigated (20). In recent study, we have presented the synthesis and characterization of a novel copolymer of vinylidene cyanide (VCN) and 2,2,2-trifluoroethyl methacrylate (MATRIF) (21). High-resolution 1 H and 13 C-NMR spectra were used to study the microstructure of the copolymer suggesting alternating tendency in this copolymerization.…”