Experimental work was concentrated on attempts to prepare copolymers from solid binary eutectics. Styrene and β-propiolactone were investigated as an example of a system comprising a vinyl and a cyclic monomer. Only a mixture of homopolymers was obtained as a result of γ-irradiation and, more generally, it is maintained that convincing evidence of copolymerization in such systems has not been presented in the scientific literature.