The influence of solvent on the apparent reactivity ratios in free radical copolymerisation reactions between itaconic acid and 2-hydroxyethyl acrylate

The copolymerisation reaction between 2-hydroxyethyl acrylate and itaconic acid has been studied in a range of solvents. In a series of reactions in protic solvents, i.e. water, methanol, ethanol, isopropanol and n-butanol, the reactivity ratios (r1 and r2) showed a distinct dependence on the solvent used. Copolymerisations in an aprotic solvent, dimethyl formamide, again yielded different r1 and r2 values but the copolymerisation behaviour was very similar to the reactions carried out in water. It was demonstrated that preferential absorption of the monomers by the copolymer occurs and while the systems did not appear to follow the explanation for the phenomenon offered by the “Bootstrap” model, the similarities were sufficient to consider the behaviour observed as a “pseudo bootstrap” effect.