The time temperature position of the glass-rubber transition of amorphous polymers and the free volume

Schwarzl, Friedrich Rudolf; Zahradnik, F.

doi:10.1007/bf01521925

Cited by 76 publications

(28 citation statements)

References 9 publications

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“…Below the glass transition temperature of poly(vinyl butyral), the shift factor only moderately decreases with temperature ( Fig. 11(c)) and a temperature shift influences the mobility of the polymer chains to a lower extent, see also the data for polystyrene in the work of Schwarzl and Zahradnik [41].…”

Section: Resultsmentioning

confidence: 98%

Viscoelastic and dielectric properties of composites of poly(vinyl butyral) and alumina particles with a high filling degree

Handge

Wolff

Abetz

et al. 2016

Polymer

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Filler-filler and filler-matrix interactions in polymer composites increase with filler concentration and strongly influence the mechanical and rheological properties of polymer composites. By means of the spouted bed spray granulation process polymer composites with an extremely high concentration of inorganic fillers can be prepared. In this work, the viscoelastic properties of highly filled composites of poly(vinyl butyral) (PVB) and alumina particles are studied in the glassy, entanglement and terminal flow regime of poly(vinyl butyral). Ceramic-polymer composites with a volume concentration of inorganic particles between 61 vol% and 77 vol% were prepared. Such large filler fractions imply a strong effect of filler-filler interactions on the viscoelastic properties of the composite. Dynamic-mechanical thermal analysis reveals that the composites are characterized by a predominantly elastic behaviour below and above the glass transition temperature of the polymer phase because of strongly pronounced filler-filler and polymer-filler interactions. A phenomenological equation is proposed in order to describe the reinforcement effect which implies an increase of storage modulus by a factor of up to four orders of magnitude. The results of frequency and strain sweeps in the oscillatory mode show that the polymer phase strongly influences the deformation of the contact network of inorganic particles. Differential scanning calorimetry and broadband dielectric spectroscopy indicate that the glass transition temperature of poly(vinyl butyral) does not significantly differ within experimental resolution for pristine PVB and the PVB phase in the composites.

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Section: Resultsmentioning

confidence: 98%

Viscoelastic and dielectric properties of composites of poly(vinyl butyral) and alumina particles with a high filling degree

Handge

Wolff

Abetz

et al. 2016

Polymer

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“…The location of the glass-rubber transition is defined by the logarithmic midpoint of the transition in creep compliance. It had been determined by means of the TNO torsional-creep apparatus for the polystyrene under investigation earlier [22]. The location of the network transition is defined by the logarithmic midpoint of the corresponding transition step in storage compliance.…”

Section: Time-temperature Shift Of the Network Transitionmentioning

confidence: 99%

Dynamic shear properties of a technical polystyrene melt

1984

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A dynamic viscometer of the Couette type is described which permits the determination of storage and loss shear modulus of polymer melts with high accuracy. For a technical polystyrene, results of measurements of storage and loss moduli are reported in the temperature interval between the rubbery plateau and degradation. From these data, the courses of storage and loss compliances and the course of the time-dependent shear compliance are derived and compared with the results of creep measurements.The frequency dependence of the storage compliance shows clearly the presence of the so-called network transition between the end of the glass transition and the onset of flow. The time-temperature shifting laws for the flow process and for the network transition are shown to obey the WLF shift equation, but with different sets of parameter values. Consequently, the complete data do not obey the timetemperature superposition law.Comparison with non-Newtonian viscosities, measured by means of a slit and a capillary viscometer attached to an extruder, shows the excellent validity of the Cox-Merz rule, provided either the absolute dynamic viscosity or the stressing viscosity are used for this comparison.

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“…(1) for polystyrene at various temperatures as indicated; applied shift-function determined in the flow region Figure 11 shows the mastercurve of the recoverable creep compliance above the glass transition, obtained by applying the time-temperature shifting law in terms of the VFTH equation [10] or WLF equation [11]. So, even when a semi-logarithmic plot is chosen for the representation of the mastercurve, figure 11 clearly demonstrates an excellent superposition of the measured curves to a mastercurve at the reference temperature To = 126.7 °C.…”

Section: Shifting Law Of the Network Transitionmentioning

confidence: 99%

Shear creep and recovery of a technical polystyrene

Link

Schwarzl

1987

Rheol Acta

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Abstract." The torsional creep and recoverable bahaviour of a technical polystyrene is reported over seven orders of magnitude of the value of the compliance from 10 -8 to 10 -1 Pa -1 and over more than seven decades in time. The results for the recoverable compliance JR(t) reveal a dispersion region seen between the glass transition and the steady-state recoverable compliance Je. The limiting value of the final dispersion Je = 4.7 • 10 -4 Pa -1 indicates a broad molecular-weight distribution. The steady-state recoverable compliance Je is independent of the temperature. The temperature dependence of the final dispersion was found to be indistinguishable from that of viscous flow. However, this temperature dependence differs significantly from that of the glass-rubber transition. A proposal has been made for the construction of creep compliance and recoverable compliance over an extended time scale.

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The time temperature position of the glass-rubber transition of amorphous polymers and the free volume

Cited by 76 publications

References 9 publications

Viscoelastic and dielectric properties of composites of poly(vinyl butyral) and alumina particles with a high filling degree

Viscoelastic and dielectric properties of composites of poly(vinyl butyral) and alumina particles with a high filling degree

Dynamic shear properties of a technical polystyrene melt

Shear creep and recovery of a technical polystyrene

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