Fundamental investigations into the free‐radical copolymerization of N‐phenylmaleimide and norbornene

Abstract

A fundamental investigation into the copolymerization of N-phenylmaleimide and norbornene via conventional free-radical polymerization techniques was conducted. Reaction conditions were optimized for molecular weight and percent yield by tuning overall concentration and initiator loading. The copolymerization kinetics were monitored using in-situ, variable temperature nuclear magnetic resonance and firstorder behavior was observed with respect to each monomer. Although the related copolymerization of norbornene and maleic anhydride was well-known to proceed in a perfectly alternating manner, the copolymerization of norbornene and N-phenylmaleimide was found to deviate from strictly alternating copolymerization behavior, producing significant amounts of sequentially enchained N-phenylmaleimide units within the polymeric backbone. This deviation from perfectly alternating behavior was confirmed by analysis of individual monomer conversion rates and by measurement of monomer reactivity ratios using the Mayo-Lewis graphical analysis method. V C 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 985-991

Determination of the Radical Reactivity Ratios of 2-(N-Ethylperfluorooctanesulfonamido)ethyl Acrylate and Methacrylate in Copolymerizations with N,N-Dimethylacrylamide by in Situ 1H NMR Analysis As Established for Styrene–Methyl Methacrylate Copolymerizations

“…In this case, it would be preferable to analyze the copolymer composition by in situ NMR spectroscopy, rather than by NMR analysis of isolated copolymer. In situ NMR analyses have been used to determine the copolymer compositions at relatively low monomer conversions (4–12%) to determine the reactivity ratios of copolymerizations following the terminal model using NLLS analysis. ,, Because in situ NMR analysis is ideal for following the relative rates of comonomer conversions, which correspond to the instantaneous copolymer composition, the Mayo–Lewis and Fineman–Ross linearization methods are also commonly used for analyses.…”

“…First, because (co)­polymer resonances are broad and barely detectable at very low monomer conversion, and require long NMR times to be quantitative, we did not determine the copolymer compositions directly as in two , of the studies; instead, we assumed that all comonomer consumed at small intervals was converted to copolymer without side reactions and used that change in monomer composition at very small conversions to calculate the resulting instantaneous copolymer compositions. Second, this means that we did not use either the overall or initial relative rates of comonomer conversions to determine the instantaneous copolymer composition, ,, which provides only a single data point for each NMR tube experiment of one initial comonomer composition. Instead, we took advantage of the compositional drift throughout the copolymerizations to analyze progressively changing comonomer feed compositions with each new NMR pulse and therefore harnessed the wealth of data available at incrementally small monomer conversions throughout each copolymerization up to 75–95% monomer conversion; i.e., each pulse of the NMR experiment corresponds to a new instantaneous copolymerization experiment.…”

Approaching new biomaterials: copolymerization characteristics of vinyl esters with norbornenes, allyl esters and allyl ethers

“…The rigid repeat unit can contribute to useful physical properties. 24,25 Copolymerization of norbornene with ethylene or propylene initiated by metal complexes affords cyclic olefin copolymers with unique properties. 26,27 Furthermore, norbornenes have been copolymerized with methacrylates to achieve useful optical properties.…”

“…The alternating copolymers synthesized by free radical polymerization at higher temperatures (65 °C) have many desirable properties such as good thermal stability, high glass transition temperature, optical transparency, high decomposition temperature, etc. The rigid repeat unit can contribute to useful physical properties 24,25 . Copolymerization of norbornene with ethylene or propylene initiated by metal complexes affords cyclic olefin copolymers with unique properties 26,27 .…”