The temperature dependence of the heat capacity of the alternating copol.vmer (ACP) of carbon mono:dde with ethylene was studied, and temperatures and enthalpies of its phase transformations were measured by adiabatic vacuum, dynamic, and isothermal calorimetry in the temperature range from 8 to 600 K. The energy of burning of ACP was measured at 298.15 K in a calorimeter with the static bomb and isothermal shell. The thermodynamic parameters of transformation of the a-form of ACP crystals into the [3-form and fusion of the 13-form were determined. The thermodynamic functions for the 0--507 K range and thermodynamic characteristics at T = 298.15 K and p = 101.325 kPa were calculated. The thermodynamic parameters of the alternating copolymerization of ethylene and CO at 0--507 K and standard pressure were calculated for the bulk reaction.Key words: copolymer of ethylene and carbon monoxide, heat capacity, thermodynamic functions; copolymerization, enthalpy, entropy, Gibbs function.The alternating copolymer of ethylene with CO is a representative of a new class of polymers, polyketones. 1-3 It can be obtained by catalytic copolymerization of the following monomers 1-5The interest in polyketones arises from the following facts, s First of all, they represent a new, almost unstudied class of polymers. The existence of the >CO--group in the macromolecules opens up new poss~ilities for modification of these polyketones, which is important from the viewpoint of ecological demands. Since data on the physicochemical properties of polyketones are limited, their identification and interpretation of results of syntheses are difficult) Data on the thermodynamic properties of polyketones are scarce. The thermograms for the crystallization and fusion regions have been obtained, and the fusion temperature and enthalpy have been estimated only for the alternating copolymer (ACP) of ethylene with CO. 3,7 To determine these values, the dependence of the fusion temperature of ACP on the presence of admixtures g described by the Flory--Huggins equation 9 has been studied.In this work, the temperature dependence of the heat capacity Co ~ of ACP in the region of 8--600 K was studied, and the temperatures and enthalpies of its phase transformations and the energy of burning at T = 298.15 K were measured by calorimetric methods. Based on the experimental data obtained, we calculated the thermodynamic characteristics of these transformations and thermodynamic functions Cp~ 7), l-P(7) -H~ 5~( 73 -S~(0), G~ -It~ and standard thermochemical parameters of the formation of ACP from simple substances and the copolymerization of ethylene with CO at 0--507 K.
ExperimentalNMR spectra were recorded on a Bruker CXP-200 instrument. IR spectra were recorded on UR-20 and Specord M-80 instruments. Calorimetric measurements were carried out on a DSM-2M instrument.ACP samples were synthesized in the Institute of Chemical Physics of the Russian Academy of Sciences by the procedure described previously. 3 Found (%): C, 64.17; H, 7.17. Calculated (%): C, 64....
