| Abstract: | The enthalpies of combustion of poly(ethylene oxide), ΔH (c)=-1178,7 ± 1,3 kJ . mol-1, and of a random copolymer of overall molar composition 0,41 (poly(ethylene oxide)) + 0,59 (poly(oxy-1,4-cyclohexylene)), ΔH (c)=-2566,4 ± 1,8 kJ . mol-1, were measured at 298,15 K by high-precision bomb calorimetry. The enthalpy of polymerisation of ethylene oxide was derived as ΔH (l → c) = -102,4 ± 1,6 kJ . mol-1. The enthalpy of copolymerisation of ethylene oxide and 7-oxabicyclo2.2.1]heptane was ΔH (l → c) = -63,0 ± 2,1 kJ . mol-1, compared with -68,1 ± 1,6 kJ . mol-1 for producing the two homopolymers in the proportion in which the monomers were present in the copolymer. It is concluded that insertion of an ethylene oxide unit into a poly(oxy-1,4-cyclohexylene) chain does not affect the strain-energy by a significant amount. |
