Thermodynamics of semi-interpenetrating polymeric networks based on crosslinked poly(cyanurate) and linear poly(urethane) in the temperature region from T→0 to 350 K

The temperature dependences of the heat capacity of linear poly(urethane) (PU) (M-n = 4 (.) 10(4)), which was synthesized from 4,4'-diphenylmethane diisocyanate, oligo(butylene glycol adipinate) (Mn = 1000), and chain-elongating agent butane-1,4-diol, and three samples of related semi-interpenetrating polymeric networks containing 25, 50, and 75 wt.% of crosslinked poly(bisphenol A) cyanurate were studied in a region of 6-350 K by adiabatic vacuum calorimetry. Their combustion energies were determined in a calorimeter with a static bomb and an isothermic shell. The thermodynamic functions of the compounds under study for the temperature region from T -> 0 to 350 K, enthalpies of combustion, and thermodynamic characteristics of formation from simple substances at T = 298.15 K and p = 0.1 mPa were calculated. The thermodynamic parameters of formation of the semi-interpenetrating networks were calculated. The dependences of the isotherms of the thermodynamic properties and thermodynamic compatibility of the semi-interpenetrating networks on their composition were determined.