Optically active polymers, 2. Copolymerization of limonene with maleic anhydride

Copolymerization of maleic anhydride (MA) and (R),(S)‐limonene (LIM) was studied in various solvents, using 2,2′‐azoisobutyronitrile (AIBN) and benzoyl peroxide (BPO) as initiators and radiation (60Co γ‐source) within the temperature range of 20–70°C. Regardless of conversion or initial comonomer feed ratios, the composition of LIM‐MA copolymers ranged from about 1 : 1 to 1 : 1,6 and was dependent on the reaction conditions, leading to a formation of materials with diverse solubilities, degrees of crosslinking and molecular weights. The main product consists of a 1 : 1 LIM‐MA copolymer with pendant 4‐methyl‐3‐cyclohexenyl residues. At higher conversion these alicyclic unsaturations lead to crosslinking. No reference to cyclocopolymerization was detected.