For the first time, ethylketene, synthesized by thermolysis of butyric anhydride, was polymerized cationically in order to obtain a novel aliphatic polyketone. Initiated by Lewis acid initiator AlBr3, this polymerization was undertaken in different solvents and at −78 °C (top polymerization yield of 57% in toluene). 1H-13C HSQC NMR experiments clearly demonstrated the polyketonic microstructure. The thermal properties of this new polymer were analyzed by DSC, TGA and X-ray diffraction: with a glass transition temperature around 70 °C and an average crystallinity of 0.34, this polymer showed a starting degradation temperature near 210 °C.
