Freezing of conformational states of poly(vinyl chloride) under pressure

O’Reilly, James M.; Mosher, R. A.

doi:10.1002/pol.1979.130171109

Cited by 16 publications

(2 citation statements)

References 13 publications

(3 reference statements)

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“…An increase in temperature therefore has the same effect on A V as an increase in pressure or a decrease in the compression rate /c. It is produced by the fast local readjustment of the macromolecular structure (collapse of the free volume via deformation of the bond angles) which freeze out the high energy conformations populated at 4 0 -6 0 K above Tg [12]. The increased number of molecular contacts hinder the changes in position of the atoms and molecules, this intra-and inter-molecular effect on the polymer vibrations being larger the higher the run temperature.…”

Section: Effect Of Temperaturementioning

confidence: 98%

“…A statistical analysis of these data, using the method of least squares [1], provided the following second order polynomials to describe these effects: logtlt(T, lc)=Ao+Ai(logar, lc)+Az(logaT, l<) 2, (12) in which the coefficients have the following values: A0 = 6.967410, AI = 0.009903 and A 2 = 0.002678.…”

Section: Combined Effect Of Temperature and Compression Ratementioning

confidence: 99%

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Longitudinal volume viscosity of poly (vinyl chloride)

Sanchez-Sancha¹,

Alemán²

1984

Rheol Acta

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Abstract:The volume flow of poly (vinyl chloride) (21~, = 45,000, To = 350 K) has been measured in an Instron Capillary Rheometer.The elastic modulus in longitudinal compression, the longitudinal volume viscosity and initial longitudinal volume viscosity, and retardation times were determined at temperatures both below (324-343 K) and above (403-453 K) the glass transition temperature Tg, and at compression rates between approximately 10 -5 and 200" 10-Ss -j.An increase in the longitudinal volume viscosity was observed for decreases in the volume deformation, increases in the compression rate and increases in temperature. T o decreased at 0.16 K/MPa. The volume flow activation energy was found to be equal to that for shear flow with a constant value of 91.37 kJ/mol.

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Section: Effect Of Temperaturementioning

confidence: 98%

Section: Combined Effect Of Temperature and Compression Ratementioning

confidence: 99%

Longitudinal volume viscosity of poly (vinyl chloride)

Sanchez-Sancha¹,

Alemán²

1984

Rheol Acta

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Non‐equilibrium processes in poly(vinyl chloride) glasses vitrified at elevated pressures

Prest

O’Reilly

Roberts

et al. 1981

Polymer Engineering & Sci

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The conformational and enthalpic changes that occur in poly(vinyl chloride) (PVC) glasses that have been vitrified from the melt under pressure have been examined by Fourier transform infrared spectroscopy and quantitative differential scanning calorimetry. It is shown that these pressures freeze in the high energy states that are characteristic of the vitrification temperature and increase the apparent glass transition temperature of the polymer. In addition, pressures in excess of the vitrification pressure, cause intermolecular effects that can be relaxed out below Tg. Both of these processes create characteristic endothermic and exothermic changes in the apparent heat capacity of the glass that appear over a period of time and are sensitive functions of the glass formation. processes as well as the subsequent annealing history. The endothermic events are interpreted as the stress perturbed volumetric relaxation process while the exotherms are associated with the release of the frozen in stresses.

show abstract

Non‐equilibrium processes in poly(vinyl chloride) glasses vitrified at elevated pressures

Prest

O’Reilly

Roberts

et al. 1981

Polymer Engineering & Sci

View full text Add to dashboard Cite

The conformational and enthalpic changes that occur in poly(vinyl chloride) (PVC) glasses that have been vitrified from the melt under pressure have been examined by Fourier transform infrared spectroscopy and quantitative differential scanning calorimetry. It is shown that these pressures freeze in the high energy states that are characteristic of the vitrification temperature and increase the apparent glass transition temperature of the polymer. In addition, pressures in excess of the vitrification pressure, cause intermolecular effects that can be relaxed out below Tg. Both of these processes create characteristic endothermic and exothermic changes in the apparent heat capacity of the glass that appear over a period of time and are sensitive functions of the glass formation processes as well as the subsequent annealing history. The endothermic events are interpreted as the stress perturbed volumetric relaxation process white the exotherms are associated withh the release of the frozen in stresses.

show abstract

Freezing of conformational states of poly(vinyl chloride) under pressure

Cited by 16 publications

References 13 publications

Longitudinal volume viscosity of poly (vinyl chloride)

Longitudinal volume viscosity of poly (vinyl chloride)

Non‐equilibrium processes in poly(vinyl chloride) glasses vitrified at elevated pressures

Non‐equilibrium processes in poly(vinyl chloride) glasses vitrified at elevated pressures

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