THERMODYNAMICS OF BUTYLMETHACRYLATE AND PERDEUTEROBUTYLMETHACRYLATE AT TEMPERATURES FROM 0 TO 330-K

The temperature dcpendence of the molar heat capacity C(p,m)-degrees o f butylmethacrylate and perdeuterobutylmethacrylate in crystalline, gl assy, overcooled liquid, and liquid states has been studied at tempera tures between 10 K and 330 K in a vacuum adiabatic calorimetric cryost at within +/- 0.002 . C(p,m)-degrees. The temperature and enthalpy of melting of the compounds have been measured. The quantities of the gla ss transition and the glassy state such as the glass-transition temper ature T(gt)-degrees, the increase in heat capacity on devitrification DELTAC(p,m)-degrees(T(gt)-degrees)), the zero-temperature entropy S(gt )-degrees(0), the configurational entropy S(conf)-degrees, and the dif ference in zero-temperature enthalpies of the substances in glassy and crystalline states {H(gt)-degrees(0) - H(cr)-degrees(0)} have been de termined. From the values obtained, the thermodynamic functions: DELTA 0(T)H(m)-degrees, DELTA0(T)S(m)-degrees and PHI(m)-degrees have been c alculated from T --> 0 to 330 K. From the enthalpies of formation of p olybutylmethacrylate and polyperdeuterobutylmethacrylate obtained from enthalpies of combustion of the polymers in highly elastic states at T = 298.15 K and p = 101.325 kPa as well as the enthalpies of polymeri zation of the monomers in bulk measured by direct calorimetry, the sta ndard enthalpies of formation DELTA(f)H(m)-degrees of liquid butylmeth acrylate and perdeuterobutylmethacrylate have been estimated. For the same physical states the standard molar entropies of formation DELTA(f )S(m)-degrees and the standard molar Gibbs function of formation DELTA (f)G(m)-degrees for the compounds have been calculated. The quantitati ve influence of the substitution of hydrogen for deuterium on the ther modynamic properties of butylmethacrylate has been revealed.