Solution copolymerization of styrene and 2‐hydroxyethyl mechacrylate.

Abstract

The rate of solution copolymerization of styrene (M1) and 2‐hydroxyethyl methacrylate (M2) was investigated by dilatometry. N,N‐dimethyl formamide, toluene, isopropyl alcohol, and butyl alcohol were used as solvents. Polymerization was initiated by α,α′‐azobisisobutyronitrile at 60°C. The initial copolymerization rate increased nonlinearly with increasing 2‐hydroxyethyl methacrylate (HEMA)/styrene ratio. The copolymerization rate was promoted by solvents containing hydroxyl groups. Two different approaches were used for the prediction of copolymerization rates. The relationships proposed for the copolymerization rates calculation involve the effects of the total monomer concentration, mole fraction of HEMA, and of the solvent type. Different reactivity ratios were found in polar and nonpolar solvents: r1 = 0.53, r2 = 0.59 in N,N‐dimethyl formamide, isopropyl alcohol and n‐butyl alcohol; r1 = 0.50, r2 = 1.65 in toluene. The usability of these reactivity ratios was confirmed by batch experiments.

Solvent effect on the free‐radical copolymerization of 2‐hydroxyethyl methacrylate with t‐butyl acrylate

“…A similar trend is obtained in the copolymerization of 2‐ethyl acrylic acid (EAA) with MAA 14. A solvent effect has also noted in the copolymerization of HEMA with S or with methacrylic monomers,15–19 with the value of the reactivity ratios dependent on the polarity of the solvents used. Because the polarity of the solvent has an important influence on the monomer reactivity ratios, this article examines the solvent effect on the reactivity ratios of the HEMA–TBA system by comparing the reported values in a solvent with a relatively high polarity (DMF) with those obtained in a nonpolar solvent (1,4‐dioxane).…”

“…Variation of the monomer reactivity ratios for other HEMA copolymerization systems as a function of the solvent has also been observed. Thus, a significant solvent effect has been noted for the copolymerization of HEMA with S,15, 16 for the copolymerization of HEMA with dodecyl methacrylate (DMA),17 or for the copolymerization of HEMA with butyl methacrylate (BMA) 18, 19. In the HEMA–S15, 16 and HEMA–DMA17 systems, the monomer reactivity ratio of HEMA presents a higher value with decreasing medium polarity.…”

Determination of the Intra- and Intermolecular Microstructure of Bulk and Emulsion Copolymers of Styrene and 2-Hydroxyethyl Methacrylate by Means of Proton NMR and Gradient Polymer Elution Chromatography

“…15 Although attention for the microstructure of S-HEMA copolymers has been very limited, the determination of reactivity ratios of the comonomer pair S-HEMA in various solvents has been reported often in literature, e g . , ref 16. Galbraith et a1.l' collected the reactivity ratios determined by various authors, but none of these reactivity ratios pertain to the bulk polymerization at 50 "C. In most cases HEMA is found to be the more reactive monomer, with the reactivity ratios of both monomers mostly being smaller than unity, which means that random copolymers are formed.…”

Nitroxide‐Mediated Polymerization of 2‐Hydroxyethyl Methacrylate (HEMA) Controlled with Low Concentrations of Acrylonitrile and Styrene

“…For HEMA/S copolymerizations, the effect of solvent was pronounced . In DMF solution, the monomer reactivity ratios for HEMA/S were 0.45/0.53 ( r s / r HEMA , 90.0 °C, 50 vol% DMF), compared to the values of 0.27/0.49, respectively, reported in bulk ( r s / r HEMA , 50.0 °C) .…”