Polymerization behaviour of 2,5‐dimethylene‐ 2,5‐dihydrofuran

Spontaneous homopolymerization of 2,5‐dimethylene‐2,5‐dihydrofuran (DDF) was studied. The polymerization rates in two different initial monomer concentrations of DDF were analyzed with the first‐order and second‐order kinetics, and the homopolymerization of DDF was found to obey the first‐order kinetics. The Arrhenius plot of the apparent rate constants at 30, 40, 50, and 60° gave an overall activation energy of 68.0 kJ/mol for the polymerization of DDF. From the comparison of the apparent rate constants at –78° and the time (the so‐called half‐life time) to decrease in half the monomer concentration for DDF with the corresponding values for p‐xylylene (QM), DDF was found to be a less reactive monomer than QM. The copolymerizations of DDF with vinyl monomers such as acrylonitrile (AN), α‐chloroacrylonitrile (CIAN), diethyl fumarate (DEF), and fumaronitrile (FN) were carried out in chloroform at 50° in the presence of AIBN to obtain the monomer reactivity ratios r1(DDF) = 30.0 ± 3.0 and r2 (AN) = 0 for the DDF‐AN system, r1 (DDF) = 1.55 ± 0.2 and r2(CIAN) = 0 for the DDF‐CIAN system, r1(DDF) = 3.88 ± 0.2 and r2(DEF) = 0 for the DDF‐DEF system, and r1(DDF) = 2.41 ± 0.1 and r2 (FN) = 0 for the DDF‐FN system, respectively. As the monomer reactivity ratios of r2 for all systems were zero, Q and e values of DDF were calculated from the combination of two r1 (DDF) values of any two copolymerization systems to be the 7.64 to 6.63 ×1021 range for Q and the –0.70 to –6.31 range for e, indicating that DDF is a highly conjugative and electron‐donating monomer.