The heat capacitiesC0p
of polybutene-1, polypentene-1, poly-4-methylpentene-1 and 4-methylphentene-1 were studied calorimetrically from 6 to (500–700)
K. Temperatures, enthalpies of melting of various crystalline forms and the parameters of the glass transition were determined.
The thermodynamic functionsH0(T)−H0(0), S0(T) andG0(T)−H0 (0) were calculated between 0 K and (500–700) K. From the calorimetric values obtained and literature data, the thermodynamic
characteristics of the following processes were estimated for the corresponding alkenes-1, andcis-andtrans-alkenes-2: the polymerization of alkenes-1, the monomer-isomerization polymerization ofcis- andtrans-alkenes-2 to polyaklenes-1 and the isomerization ofcis- andtrans-aklenes-2 to alkenes-1 in the same temperature interval at standard pressure.
The heats of solution of tetrabutylammonium bromide have been measured in mixtures of formamide (FA) with methanol (MeOH)
and ethylene glycol (EG) at 313.15 K by calorimetric method. The standard enthalpies of solution in binary mixtures have been
extrapolated to infinite dilution by Redlich–Rosenfeld–Meyer type equation using the literary data at 298.15 K and the present
paper data at 313.15 K. The Debye–Hückel limiting law slope AH required for calculation of the ∆solH0 value has been obtained with application the new additive scheme of determination of the physic-chemical characteristics
of binaries. The scheme is tested on the example of Bu4NBr solutions in FA–MeOH mixture at 298.15 K. Its application yields the ∆solH0 value very closed on the ones determined with the real (non-additive) characteristics of binaries. The standard enthalpies
of solution extrapolated by Redlich–Rosenfeld–Meyer type equation are in a good agreement with the ones computed in terms
of the Debye–Hückel theory in the second approximation. The heat capacities characteristics of Bu4NBr have been calculated in H2O–FA, MeOH–FA and EG–FA mixtures using the literary and present data. The sequence of solvents H2O > FA > EG > MeOH located on their ability to solvophobic solvation found by us earlier for enthalpic characteristics is
confirmed by the ∆Cp0 values. The comparison of thermochemical characteristics of Bu4NBr solutions in aqueous and non-aqueous mixtures containing FA has been carried out. The own structure of water remains in
the region of small additions of formamide to co-solvents. It considerably differs the H2O–FA mixture from the investigated non-aqueous systems.
DSC studies of melting process of annealed native structures and postdenatured ones in low-amylose starches with different
degrees of hydration were carried out. The starch recrystallization at different thermal treatments of the samples was studied
both after the complete and partial destroy of native structures. It has been shown that native structures as well as postdenatured
ones possess the ability to perfection, which is most clearly seen at the annealing at temperatures inside their melting ranges.
The results obtained demonstrate that at the same duration of annealing the process of crystal perfection for secondary starch
structures proceed more intensively compared to the native ones. The presence of the remained native structures in partial
melt in contrast to the remained gel ones restricts the ability of the recrystallized structures to perfection.
By adiabatic vacuum and dynamic calorimetry, heat capacity for poly[bis(trifluoroethoxy)phosphazene] has been determined over the 6–620 K range. Physical transformations of the polymer on its heating
and cooling have been detected and characterized. Smoothed heat capacity Cp0(T) and standard thermodynamic functions (H0(T)-H0(0), S0(T) and G0(T)-H0(0)) of poly[bis(trifluoroethoxy)phosphazene] have been evaluated for the temperature range from T→0 to 560 K. The standard entropy of formation ΔfS0 at T=298.15 K has been also determined. Fractal dimensions D in the heat capacity function of the multifractal variant of Debye’s theory of heat capacity of solids characterizing the
heterodynamics of the tested polymer have been determined.
Data on synthesis, thermal behavior and thermodynamic properties for the NZP phosphates NaMe2(PO4)3 and Na5Me(PO4)3 (Me=Ti, Zr, Hf) are reported. The compounds were synthesized by sol-gel method and solid-state reactions and characterized by
X-ray powder diffraction, IR spectroscopy, electron microprobe and chemical analysis. Their thermal behavior was studied by
the DTA measurements. The heat capacities of the phosphates were measured between temperatures 7 and 650 K. The fractal dimensions
for the phosphates were calculated. The obtained thermodynamic characteristics of these phosphates and also literature data
for the compounds of NZP type structure are summarized.
In an adiabatic vacuum calorimeter the temperature dependence of the heat capacity Cp0 of 1,3,5,7-tetramethyl-1,3,5,7-tetrahydrocyclotetrasiloxane and polymethylhydrosiloxane on its basis was measured between
6 and 350 K mainly with accuracy of about 0.2%. Two-phase transitions corresponding, probably, to the fusion of cis-and trans-conformations of the monomer as well as the glass transition of the polymer were detected. The results obtained were used
to calculate the thermodynamic functions Cp0, H0(T)-H0(0), S0(T), G0(T)-H0(0) of the monomer and polymer in the range from T→0 to T=340 K, and to estimate the zero entropy S0(0) of amorphous polymer. Standard entropies of formation ΔSf0 of the tested monomer and polymer at T=298.15 K as well as the entropy of synthesis of polymethylhydrosiloxane from 1,3,5,7-tetramethyl-1,3,5,7-tetrahydrocyclotetrasiloxane
over the range from T→0 to 340 K were estimated. The value of fractal dimension D in the heat capacity function of the multifractal variant of
the Debye’s theory of heat capacity was found to be 1.5 for polymer in the 18–35 K range, that testifies to its layer-chain
The enthalpies of solution of l-proline have been measured in aqueous urea solutions at 0–6 mol urea kg−1 water at 288.15, 298.15, 308.15, and 318.15 K by the calorimetric method. The two-parameter relation connecting the values of solution enthalpies of proline with urea concentration and temperature has been obtained. The enthalpy and heat capacity parameters of pair interaction of l-proline with urea in water have been computed. Using the thermodynamic relations, the temperature changes of reduced enthalpy, and also the change of entropy and reduced Gibbs energy of solution of l-proline in aqueous solutions of urea at the temperature rise from 288 to 318 K have been determined. Their comparison with the data for glycine and l-alanine has been carried out. It has been shown that the entropy–enthalpy compensation (Barclay–Butler rule) takes place for dissolution and transfer processes.
The enthalpies of solution of tetraethyl- and tetra-n-hexylammonium bromides have been measured in mixtures of formamide with ethylene glycol at 298.15 and 313.15 K in the whole mole fraction range by the calorimetric method. The standard enthalpies of solution in binary mixtures have been calculated with Redlich–Rosenfeld–Meyer type equation. The enthalpy and heat capacity parameters of pair interaction of organic electrolytes with EG in FA and with FA in EG have been computed and discussed. The enthalpy interaction parameters of single ions with EG in FA medium have been evaluated and compared with those for ion–water and ion–MeOH interaction in FA. The standard heat capacities of solution have been evaluated. The excess enthalpies of solution, ΔsolHE, of Et4NBr, Bu4NBr, and Hex4NBr have been determined. The ΔsolHE values are positive for Et4NBr and negative for Bu4NBr and Hex4NBr and become more negative from Bu4NBr to Hex4NBr.
Enthalpies of solution of tetra-n-hexylammonium bromide in anhydrous methanol (MeOH), formamide (FA), and ethylene glycol (EG) have been measured at 298.15 and 313.15 K. The integral solution enthalpies (ΔsolHm) of Hex4NBr and literature data for Et4NBr and Bu4NBr have been extrapolated to infinite dilution using the Redlich–Rosenfeld–Meyer-type equation to give the corresponding standard enthalpies of solution (ΔsolH0). Linear correlation between ΔsolH0(Bu4NBr) and ΔsolH0 (Hex4NBr) has been obtained in MeOH, FA, and EG. Relations allowing to predict the ΔsolH0 value of Hex4NBr in FA, NMF, DMF, and NMA at various temperatures have been proposed. The integral heat method has been employed to obtain partial molar heat capacities of the tetraalkylammonium bromides in MeOH, FA, and EG. It has been shown that the values of Et4NBr and Bu4NBr in methanol and formamide determined by this method are in good agreement with values obtained by the flow calorimetry data.
In an adiabatic vacuum calorimeter, the temperature dependence of the heat capacity Cp of phenylated polyphenylene and initial comonomer 1,4-bis(2,4,5-triphenylcyclopentadienone-3-yl)benzene was studied between
6 and 340 K with an uncertainty of about 0.2%. In a calorimeter with a static bomb and an isothermal shield their energies
of combustion DUcomb were measured. From the experimental data, the thermodynamic functions Cp0 (T), H0(T)-H0(0), S0(T)-S0(0), G0(T)-H0(0) were calculated from 0 to 340 K, and standard enthalpies of combustion ΔHcomb0 and thermodynamic parameters of formation-enthalpies ΔHf0, entropies ΔHf0, Gibbs functions ΔGf0 - of the substances studied were estimated at T=298.15 K at standard pressure. The results were used to calculate the thermodynamic characteristics (ΔHf0 ,ΔSf0, ΔGf0) of phenylated polyphenylene synthesis in the range from 0 to 340 K.