The present work reports on a reinvestigation of a radical polymerizable lactide derivative since the polymerization properties were only poorly studied in the first publication in 1969. The optically active methylenelactide was polymerized by free radical polymerization in solution using AIBN as an initiator and resulted in isotactic-biased atactic optically active poly(methylenelactide) according to 1 H NMR and 13 C NMR spectroscopies and specific rotation angle measurements [α] 20 D = −38.5 ± 0.5°. The molecular weights range between 4 × 10 4 and 1 × 10 5 g mol −1 with dispersities of ca. D = 2.5 and a detected glass transition temperature of 244 °C. IR spectra of the polymers indicate different ester reactivities (ν a = 1779 cm −1 , ν b = 1755 cm −1 ) that can be referred to as neighboring-group effects. These highly activated esters react readily with nucleophiles in polymer analogous reactions. Thus, the aminolysis of poly(methylenelactide) was performed under mild conditions with varied amines. In the case of aminolysis with tetrahydrofurfurylamine, a nonstable cloud point in water was observed.

The first detailed study on free-radical polymerization, copolymerization and controlled radical polymerization of the cyclic push–pull-type monomer methylenelactide in comparison to the non-cyclic monomer α-acetoxyacrylate is described. The experimental results revealed that methylenelactide undergoes a self-initiated polymerization. The copolymerization parameters of methylenelactide and styrene as well as methyl methacrylate were determined. To predict the copolymerization behavior with other classes of monomers, Q and e values were calculated. Further, reversible addition fragmentation chain transfer (RAFT)-controlled homopolymerization of methylenelactide and copolymerization with N,N-dimethylacrylamide was performed at 70 °C in 1,4-dioxane using AIBN as initiator and 2-(((ethylthio)carbonothioyl)thio)-2-methylpropanoic acid as a transfer agent.