Changes in free volume and mechanical properties of PVC films incurred by quenching and aging

Lee, Howard H. D.; Garry, Frederick J. Mc

doi:10.1080/00222349008212333

Cited by 18 publications

(5 citation statements)

References 28 publications

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“…The solid lines were calculated by eqs and for the TNM parameters reported for polyvinyl chloride, PVC (β = 0.23, σ = 1.571 K –1 ), selenium glass, Se (β = 0.58, σ = 0.257 K –1 ), and As 2 S 3 glass (β = 0.82, σ = 0.095 K –1 ) . Points correspond to experimental data for dilatometric experiments − (open symbols) and calorimetric experiments ,− (closed symbols).…”

Section: Discussionmentioning

confidence: 99%

Structural Relaxation Rate and Aging in Amorphous Solids

Málek

2023

J. Phys. Chem. C

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The structural relaxation in amorphous materials is discussed within the Tool−Narayanaswamy−Moynihan model (TNM), the Kovacs−Aklonis− Hutchinson−Ramos model (KAHR), and the entropy-based Adam−Gibbs− Scherer−Hodge model (AGSH). These three phenomenological models are most frequently used for the description of experimental structural relaxation data by a suitable set of parameters obtained by curve fitting. The parameter sets reported in the literature for 250 different amorphous material compositions are analyzed on the basis of the isothermal relaxation rate R depending on the nonexponentiality parameter β and the nonlinearity contribution, defined for the TNM, KAHR, and AGSH models as σ = −(dln τ/dT f ) i . The R 10 calculated at 10 K below T g represents a scale for the structural relaxation rate. It describes the structural relaxation kinetics in very different amorphous materials such as organic polymers, epoxy resins, sugars, hydrated starch, simple organic molecules, oxide glasses, chalcogenide glasses, halide glasses, metallic glasses, volcanic glasses, and tektite. This approach can be used for the kinetic comparison of structural relaxation behavior in different amorphous materials as well as in the assessment of the aging treatment and composition design for their future applications.

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Section: Discussionmentioning

confidence: 99%

Structural Relaxation Rate and Aging in Amorphous Solids

Málek

2023

J. Phys. Chem. C

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“…It has been proposed that physical aging takes place in the temperature range between the β relaxation, T β , and T g , where T β refers to the first (i.e., highest) secondary transition associated with the small-scale, subsegmental, local intramolecular motions about the flexible linkages in the polymer chain in the glass state . However, some evidence that physical aging is possible at temperatures below the β relaxation has been reported . In any case, the β relaxations for the glassy polymers studied in this work are far below room temperature (see Table ), and investigation of how these relaxations may affect the aging process is beyond the scope of this study.…”

Section: Introductionmentioning

confidence: 88%

Effect of Temperature on Physical Aging of Thin Glassy Polymer Films

2005

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The effect of temperature on the kinetics of physical aging of thin films formed from two amorphous glassy polymers, polysulfone based on bisphenol A and poly(2,6-dimethyl-1,4-phenylene oxide), was investigated by monitoring the changes in gas permeability and refractive index. Films with different thicknesses were subjected to isothermal aging at three temperatures, ranging from 35 to 55 °C, for a period of aging of more than 200 days. The rate of permeability loss and the rate of densification determined from the refractive index change by using the Lorentz−Lorenz equation were found to increase with aging temperature. Similar qualitative trends of aging rate were noted by the two measurements. The combination of effects of aging temperature and film thickness on aging behavior were studied and compared with previous research.

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“…Many studies have been presented on the kinetics of this process. Some of them are based on the measurement of the rate of evolution of polymer thermodynamics properties like volume ,− and enthalpy ,− during the aging process, while others deal with the strong effect on the polymer mechanical properties like creep, stress relaxation, yield, and dynamic behavior. − Other attempts to clarify the aging process have been done through fluorescence spectroscopy, − electron spin resonance spectroscopy, and various scattering techniques. − A review of all these methods is given by Hutchinson …”

Section: Introductionmentioning

confidence: 99%

Positron Annihilation Lifetime Spectroscopy for Measuring Free Volume during Physical Aging of Polycarbonate

et al. 2002

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Free volume relaxation of polycarbonate (PC) as a function of aging time was investigated by means of positron annihilation lifetime spectroscopy at three different temperatures below the PC glass transition temperature. A clear decrease of the intensity of orthopositronium (o-Ps) was observed, while the o-Ps lifetime remained substantially unchanged. This was attributed to a decrease in the number of cavities in the system. The process was successfully modeled according to the Struik model, which describes a relaxation time dependent on both the temperature and the distance from equilibrium.

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Changes in free volume and mechanical properties of PVC films incurred by quenching and aging

Cited by 18 publications

References 28 publications

Structural Relaxation Rate and Aging in Amorphous Solids

Structural Relaxation Rate and Aging in Amorphous Solids

Effect of Temperature on Physical Aging of Thin Glassy Polymer Films

Positron Annihilation Lifetime Spectroscopy for Measuring Free Volume during Physical Aging of Polycarbonate

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