The thermal stability of amorphous alloys is often interpreted using the heat of mixing [DELTA][H.sup.mix].
Inoue, "Classification of bulk metallic glasses by atomic size difference, heat of mixing and period of constituent elements and its application to characterization of the main alloying element," Materials Transactions, vol.
Their thermodynamic properties, such as the adsorption enthalpy, DHa, molar evaporation enthalpy, DHv, the sorption enthalpy, DH1s, sorption free energy, DG1s, sorption entropy, DS1s , the partial molar free energy, DG1[?], the partial molar heat of mixing
, DH1[?], at infinite dilution were studied by inverse gas chromatography.
5 divided by R is equal to the heat of mixing, where R is the gas constant.
The heat of mixing is almost independent of the sample thickness.
DDB consists of five modules which may be purchased as a complete set or in part: The Vapor-Liquid-Equilibrium (VLE) Data Bank, The Heat of Mixing
Data Bank (HE), The Activity Coefficient at Infinite Dilution Data Bank (ACT), The Gas Solubility Data Bank (GLe), and The Excess Heat Capacity Data Bank (CPE).
Heat of mixing is introduced as a guide for phase stability predictions of polymer mixtures, and an appropriate equation is presented for it.
It must be noted that the noncombinatorial entropy contribution that has not been taken into account in Eq 1 can also affect the Gibbs free energy of mixing (9), but for polymer mixtures it has been demonstrated that the heat of mixing contribution often dominates the other contributions (10, 11).
where [delta][H.sup.s] is the experimental heat of solution and [delta][H.sup.m] is the heat of mixing. Thus the temperature dependence of [varphi] is simply the sum of the molar heat of fusion of the additive and its partial molar heat of mixing with the polymer.
Its [delta][H.sup.s] is lower than [delta][H.sup.f], implying a negative heat of mixing, and the excess entropy of mixing is slightly negative.
The equilibrium-swelling ratio can be curve-fitted to a van't Hoff plot, and the heat of mixing
[delta]H for different dosages are listed in Table 2.
Another example where a negative heat of mixing
between block and blend component has been found to result in a good compatibilizing effect is the emulsifying activity of poly(styrene-b-methyl methacrylate) in poly(vinylidene fluoride)/Noryl blends studied by Outhadi et al.