N. N. Smirnova

Calorimetric study of thermodynamics of production of polybutene-1, polypentene-1, 4-methylpentene-1 and properties of reagents between 0 and 670 K

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.ZusammenfassungKalorimetrisch wurden im Temperaturintervall von 6 bis (500–700) K die WärmekapazitätenC0p von Polybuten-1, Polypenten-1, Poly-4-methylpenten-1 und 4-Methylpenten-1 untersucht. Dabei wurde die Schmelztemperatur, die Schmelzenthalpie verschiedener kristalliner Formen und die Parameter für die Glasumwandlung bestimmt. Für die Temperatur von 0 bis (500–700) K wurden die thermodynamischen FunktionenH0(T)−H0(0),S0(T) undG0(T)−H0(0) errechnet. Anhand der erhaltenen kalorimetrischen Werte und der Literaturangaben wurden die thermodynamischen Charakteristika der nachstehenden Prozesse für die entsprechenden Alken-1 sowiecis- undtrans-Alken-2 Verbindunge geschätzt: Polymerisierung von Alken-1, Monomerisomerisations-Polymerisierung voncis- undtrans-Alken-2 zu Polyalken-1 und die Isomerisation voncis- undrans-Alken-2 zu Alken-1 im selben Temperaturintervall unter Standarddruck.

Thermodynamics of an alternating carbon monoxide-ethylene-propylene copolymer in the region of T → 0 to 500 K

The heat capacity of a ternary alternating carbon monoxide-ethylene-propylene copolymer with a content of -CO-CH2-CH(CH3)- units of 13.3 mol % and the temperatures and enthalpies of its physical conversions are studied by adiabatic and differential scanning calorimetry in the region of 6–500 K. The combustion energy of the copolymer in the condensed state is measured calorimetrically at 298.15 K. The thermodynamic functions in the region of T → 0 to 455 K and the thermodynamic characteristics of the formation of this copolymer at T = 298.15 K and its synthesis within the range of T → 0 to 300 K are calculated.

Thermodynamics of triple alternating copolymer ethylene—carbon monoxide—propylene

The temperature dependence of heat capacity of triple alternating copolymer ethylene—carbon monoxide—propylene with 23.4 mol.% of propane fragments was studied for the first time by adiabatic and dynamic calorimetry over the range of 6–480 K. The energy of copolymer combustion at 298.15 K was measured in isothermic calorimeter with stationary bomb. The thermodynamic parameters of phase and physical transitions were determined. The standard thermodynamic functions Cp○(T), H○(T) − H○(0), S○(T) − S○(0) and G○(T) − H○(0), for region from T→ 0 to 320 K, the standard enthalpy of combustion and thermodynamic characteristics of formation of the studied compound at 298.15 K were calculated from the experimental data. The thermodynamic parameters of alternating copolymerization of CO with ethylene and propylene at standard pressure over 0–300 K region were detemined.

Influence of the molecular weight of polystyrene on its thermodynamic properties

The thermodynamic properties of a series of polystyrene samples with different molecular weights (Mw was varied from 2.5·103 to 6.57·104) were studied by precision adiabatic vacuum, high-accuracy dynamic, and combustion calorimetry: temperature dependences of the heat capacity in a wide temperature range, thermodynamic characteristics of glass transition and glassy state under standard pressure, and energy of combustion. The thermodynamic functions C○p(T), H○(T) - H○(0), S○(T) - S○(0), and G○(T) - H○(0) of polystyrene with different molecular weights, enthalpies of combustion ΔcH○, thermodynamic parameters of formation from simple substances ΔfH○, ΔfS○, and ΔfG○ at T = 298.15 K, and parameters of their synthesis from monomers were calculated from the experimental data. The temperature dependences of the heat capacity for a region of 0–380 K, glass transition temperatures, and thermodynamic characteristics of formation and synthesis of polystyrene depending on its molecular weight were examined.