Ketene-based aliphatic polyketones obtained by cationic copolymerization of dimethylketene (DMK) with diethylketene (DEK) or diphenylketene (DPK): synthesis, characterization and reactivity ratio estimation

Cationic copolymerizations of different ketoketenes are conducted to explore the structure and properties of the afforded copolymers. Diethylketene (DEK) and diphenylketene (DPK) are both copolymerized with dimethylketene (DMK), via a cationic mechanism using the mixture AlCl3 / (CH3)3CCl as initiator. The experiments confirmed that two series of polyketones, containing a main DMK chain comprising few DEK or DPK units, are successfully obtained. The reactivity ratios are calculated. The structures and thermal performances of the obtained copolymers are discussed. An interesting DMK / DEK copolymer with a broad processing window was obtained (Tm = 164 °C, $${T}_{d}^{5\%}$$ = 259 °C).