Using ¹H‐NMR spectroscopy for the kinetic study of the in situ solution free‐radical copolymerization of styrene and ethyl acrylate

Abstract

The free-radical copolymerization of styrene and ethyl acrylate in benzene-d 6 as the solvent in the presence of benzoyl peroxide as an initiator at 708C was studied by online 1 H-NMR spectroscopy. The chemical composition of the copolymer at different reaction times was calculated from the conversion of the monomers to the copolymer, and then the reactivity ratios of styrene and ethyl acrylate were determined at both low and high conversions. Data for the overall monomer conversion versus the time were used to estimate the ratio k p k t À0.5 for different compositions of the initial feed (k p is the propagation rate constant, and k t is the termination rate constant). k p k t À0.5 increased with an increasing molar fraction of ethyl acrylate in the initial feed. The monomer mixture and copolymer compositions versus the overall monomer conversion were calculated with the data of 1 H-NMR spectra. The incorporation of the styrene monomer into the copolymer structure was more favored than that of the ethyl acrylate monomer. Reducing the molar fraction of styrene in the initial feed intensified this. Drawing the molar fraction of styrene (or ethyl acrylate) in the copolymer chains versus that in the initial feed showed a tendency of the system toward random copolymerization.

In Situ NMR and Modeling Studies of Nitroxide Mediated Copolymerization of Styrene and n-Butyl Acrylate

“…7À10 Kinetic parameters such as reactivity ratios have been determined from in situ 1 H NMR data for different systems. 8,9 Information on copolymer composition has also been reported from in situ 1 H NMR data. 2,9…”

Facile Synthesis of Thermoresponsive Poly(NIPAAm-g-PDMS) Copolymers Using Room Temperature Alkylborane Chemistry

“…The reactivity ratios for NIPAAm and MA-PDMS were determined using online 1 H NMR spectroscopy to monitor the reaction as previously described. − Spectra were recorded as a function of time, and peak averaging of the NIPAAm proton peaks at δ 5.66 and 4.97, and the MA-PDMS geminal protons at δ 5.54 and 5.03 were used to track the monomer conversions using the acetone- d 6 peak (δ 2.05) or the ethyl acetate satellite peaks (δ 4.55) as an internal reference for integration.…”

Kinetic study of the free‐radical polymerization of vinyl acetate in the presence of deuterated chloroform by 1H‐NMR spectroscopy

“…There was good agreement between the model and experimental results, which indicated the accuracy of the calculated rate constants. As a result, online 1 H‐NMR kinetic experiments could be used to reasonably evaluate the kinetics of the free‐radical reactions in the whole range of conversion 19–21…”

“…Online 1 H‐NMR spectroscopy has been used frequently for homopolymerization and copolymerization systems to investigate the kinetics of polymerization reactions with respect to, for example, the overall polymerization rate coefficient and the monomer reactivity ratios, copolymer composition, and stereoregularity (in the case of copolymerization) 19–21. In this study, possibility of using 1 H‐NMR kinetic experiments for the investigation of the kinetics of the free‐radical telomerization of VAc with deuterated chloroform (CDCl 3 ) as a telogen in the presence of 2,2′‐azobisisobutyronitrile (AIBN) initiator was examined.…”