The predicted
enthalpy of reaction of the 2K PU formulation in Table 1 was approximately 142 J/g assuming an average heat of reaction of 105 kj/mole for the isocyanate-hydroxyl reaction.
TMT is an analytical method used to determine the content of substances, which is measured on the basis of different values of
enthalpy of reaction [12].
where [n.sub.prod] and [n.sub.react] are the stoichiometric coefficients of reaction products and reactants, respectively, and [DELTA][H.sup.o.sub.prod] and [DELTA][H.sup.o.sub.react] are the variations of
enthalpy of reaction products and reactants, respectively.
Agreement is also shown between the calculated
enthalpy of reaction (2) with Ikeda et al.
Although the reaction heat for the copolymerization UP/styrene or for the homopolymerization of styrene are not rigorously equal, the structure of these double bonds (conjugated with an aromatic ring for styrene, or with carbonyl functions for UP) are close enough to consider, in a first approach, that the molar
enthalpy of reaction is the same for the homo- and copolymerization.
The reaction thermodynamic parameters indicate that P2 complex, [sup.1][O.sub.2] ([sup.11][[DELTA].sub.g]) + S[O.sub.2], formation is exothermic with
enthalpy of reaction, -170.708 kcal/mol, in comparison with the original reactants.
At concentrations below 5% there is no significant contribution to the
enthalpy of reaction for the epoxy + montmorillonite two part mixtures.
From the DSC plots, the
enthalpy of reaction ([DELTA][H.sub.p]) and the temperature, which corresponds to the peak exotherm, were determined; see Fig.
A Mettler thermoanalyser TA 4000 DSC, operating in the -100 [degrees] C to 300 [degrees] C temperature range and equipped with a liquid nitrogen cooling system, was used to determine
enthalpy of reaction, [T.sub.g] (detected at the inflexion point of the deflection heat capacity change), and variation of the heat capacity [Delta][C.sub.p] through the [T.sub.g] of the resin samples.