A Transition above T<sub> g </sub> in Amorphous Polymers as Shown by the Spin-Probe Technique

Smith, Peter M.; Boyer, Raymond F.; Kumler, Philip L.

doi:10.1021/ma60067a013

Cited by 28 publications

(7 citation statements)

References 4 publications

(6 reference statements)

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“…These c r o s s comparisons of TBA data on PS, PMMA, PIB, and PBD suggests rather complete agreement with other methods and hence rule out the artifact charge as any major effect in the TIlp region with TBA data. liquid state behavior, The NMR data of Sillescu et al [93,94] cited earlier a r e pertinent. This is a high frequency method which further adds to the confusion.…”

Section: H I S T O R I C a L P E R S P E C T I V E O N T H E L I Q U mentioning

confidence: 94%

“…The NMR studies of Sillescu et al [93,94] on ring-and sidechaindeuterated PS's suggested a transition region above which motion of phenyl and chain segments a r e about equally rapid, the phenyl motion having been more rapid below this temperature. FTIR studies [go] of several anionic PS's show that asymmetric CH stretching (2924 cm-') and out-of-plane H motion (699 cm" a r e involved at T prominent at Tpp'.…”

Section: H I S T O R I C a L P E R S P E C T I V E O N T H E L I Q U mentioning

confidence: 96%

“…The Sanders and Ferry paper [66] indicates that butyl rubber of M = 200,000 is not self-supporting in the Fitzgerald apparatus, but requires some vulcanization, In the one systematic study reported thus f a r , Gillham et al [31] have demonstrated by TBA that T and TQQ a r e both lowered about the g same amount by a given level of diluent. This fact was utilized by Smith et al [94] t o lower TPQ of PS sufficiently so that the ESR spin probe would not suffer thermal damage. In principle, one can c a r r y out an experimental search for TPP isothermally by bringing the desired transition down and then below the selected temperature with increasing amounts of diluent.…”

Section: Qqmentioning

confidence: 99%

“…We suggest that this sample anneals at 20°C over long periods of time, giving r i s e to the sharp Axelson and Mandelkern [93] report for an atactic PP of unspecified molecular weight Tc = 30°C for a T /T of 1.20. Smith et al [94,95] Considering all experimental evidence, there is a T > T o r TpQ relaxation (transition) in atactic PP. TBA, ESR, and "C-NMR a r e not likely to be influenced by traces of crystallinity.…”

Section: S O T a C T I C P S ( I -P S )mentioning

confidence: 99%

“…The ESR study [94,95] with isotactic PB-1 showed no slope change in a log 7C-T plot even up to the melting point on a specimen of 64% crystallinity. This result verified expectations about the absence of TQp in a highly crystalline polymer.…”

Section: S O T a C T I C P S ( I -P S )mentioning

confidence: 99%

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Dynamics and thermodynamics of the liquid state (T < T_g) of amorphous polymers

Boyer

1980

Journal of Macromolecular Science, Part B

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A B S T R A C TThe liquid state behavior of the following atactic polymers has been reviewed: the alkyl and cycloalkyl methacrylates; polyisobutylene; polybutadiene, its random copolymers with styrene and acrylonitrile, and S-B diblocks; polystyrene; and the poly-cuolefins C3, C5, and C Just as T manifests itself through time-dependent (relaxational) and thermodynamic (transition) effects, so also does a T > T transition (relaxation) found generally in the range of 1.1 t o 1.3 T but mostly near 1 . 2 T This is designated as TQQ, a liquidl-liquid transition. T a~ is found, usually by a variety of dynamic, thermodynamic, and probe methods, in all of the above classes of polymers plus iso-PMMA, which also has a weak T < T o r T relaxation. With increasing syndiotactic content, PMMA's reveal strengthening T and T processes. Relaxation maps plotting log frequency-T TQQ. tion enthalpy about half that at T when both are observed some 50-100°K above their very low frequency values. Probe methods 6' g g g g' 2 g P P QQ-1 a r e presented for PBD and PIB, showing both T and g The latter exhibits non-Arrhenius behavior with an activag 461 Copyright 0 198 1 by Marcel Dekker, Inc. Downloaded by [Tulane University] at 09:04 05 January 2015 462 BOYER such as IR, "C-NMR, ESR with spin probes, depolarization of fluorescence, and thermally stimulated current seem unusually well suited to studies of the liquid state. The earliest concept of a TPL is that of Ueberreiter in 1943; the earliest experimental evidence is the torsion pendulum data of Schmieder and Wolf on PIB in 1953 and PMMA in 1957. TLP is inherently weak comparedto T and its strength is polymer specific, being relatively strong in PIB, weak in PBD. TLp is compared with the "slow process"of F e r r y and co-workers, ascribed t o slippage of dangling entanglements. TPQ occurs also below the entanglement molecular weightMc.Modern statistical methods such a s regression analysis are used to analyze T > T data for the presence o r absence of weak transitions, especially V-T and C -T data. The possibility of artifacts in some methods makes it imperative to search for T P p by many alternate methods, It is shown that isothermal V -P plots are more revelatory of TLL than a r e isobaric V-T plots. The use of Wood's variation of the Tait equation relating bulk modulus and pressure is useful in some cases for locating liquid state relaxations. Preliminary estimates of d(TQP)/dP, presented for PnBMA, P(cyclohexy1 MA) and a-PS, a r e in the range of 50-70 K/kbar, i.e. , 2-3 times the well known values for dT dP. A phase dualism hypothesis by Frenkel and Baranov suggests that TPL represents competition between segment-segment (liquid-like) behavior and the tendency of the macromolecule t o act as a gas at high temperature, Melt elasticity measurements on PS reveals a molecular weight dependent transition which appears to be TPQ ,The enthalpy of activation decreases by a factor of two from below to above TPp. The term "thermodynamic" in the title signifies use of quasi-equilibrium typ...

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Section: H I S T O R I C a L P E R S P E C T I V E O N T H E L I Q U mentioning

confidence: 94%

Section: H I S T O R I C a L P E R S P E C T I V E O N T H E L I Q U mentioning

confidence: 96%

Section: Qqmentioning

confidence: 99%

Section: S O T a C T I C P S ( I -P S )mentioning

confidence: 99%

Section: S O T a C T I C P S ( I -P S )mentioning

confidence: 99%

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Dynamics and thermodynamics of the liquid state (T < T_g) of amorphous polymers

Boyer

1980

Journal of Macromolecular Science, Part B

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Regression analysis studies of polymer transitions II. T_II from specific heat and other data for polyisobutylene

Boyer¹,

Enns²

1986

J of Applied Polymer Sci

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SynopsisLinear regression analysis studies with residuals of heat capacity vs. temperature C C , vs. T) data above the glass transition temperature (T,) for polyisobutylene (PIB) T,, is plausible in terms of the Frenkel-Baranov phase dualism mechanism. A complete relaxation map (log f vs. 1IT) has been assembled with frequencies from lo-* to 1O'O Hz and temperatures from 150 to 500 K. It shows T p , T,, TI, and methyl group rotation, all based on data in the literature. The molecular weight dependence of T, and T,, and the low resiliency of butyl rubber as it relates to T,, are discussed in the appendices.

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Contributions of torsional braid analysis to T_u

Boyer

1979

Polymer Engineering & Sci

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The accomplishments of Borden Award Winner John K. Gillham and his colleagues using Torsional Braid Analysis (TBA) and Differential Scanning Calorimetry (DSC) to investigate the T, and T > T, or Tll regions of anionic and thermal polystyrenes (PS) are evaluated and related to work on PS and other polymers and to controversies surrounding TBA and the T,, transition. Arguments are presented to refute the contention that Tll by TBA is an artifact produced by the braid and the contention that T I , has a relaxational nature but no thermodynamk basis. Two distinct behavior patterns are found for T,, vs log M , plots: quasi-static methods such as DSC on fused films show T,, to level off above M , and approach an asymptotic value of -435K; dynamic methods involving melt flow show that T I , increases without limit above M , because of entanglements. A compilation is presented of25 investigations ofT,, on polybutadiene, poly(methy1 methacry late) (PMMA), PS, plasticized PS, and atactic polypropylene, involving twenty experimental techniques. The behavior of zero shear melt viscosity for PS is summarized. Gillham's work has not only led to clarification of many isolated papers in the literature but has also inspired various parallel experimental and literature studies on TI!. We conclude that Tl, is a molecular level transition which, like T,, exhibits both kinetic (relaxational) and thermodynamic aspects. It is shown that heat capacity should be a more sensitive method than dilatometry for studying the T,, transition.

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A Transition above T_g in Amorphous Polymers as Shown by the Spin-Probe Technique

Cited by 28 publications

References 4 publications

Dynamics and thermodynamics of the liquid state (T < T_g) of amorphous polymers

Dynamics and thermodynamics of the liquid state (T < T_g) of amorphous polymers

Regression analysis studies of polymer transitions II. T_II from specific heat and other data for polyisobutylene

Contributions of torsional braid analysis to T_u

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A Transition above T g in Amorphous Polymers as Shown by the Spin-Probe Technique

Cited by 28 publications

References 4 publications

Dynamics and thermodynamics of the liquid state (T < Tg) of amorphous polymers

Dynamics and thermodynamics of the liquid state (T < Tg) of amorphous polymers

Regression analysis studies of polymer transitions II. TII from specific heat and other data for polyisobutylene

Contributions of torsional braid analysis to Tu

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Product

Resources

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A Transition above T_g in Amorphous Polymers as Shown by the Spin-Probe Technique

Dynamics and thermodynamics of the liquid state (T < T_g) of amorphous polymers

Dynamics and thermodynamics of the liquid state (T < T_g) of amorphous polymers

Regression analysis studies of polymer transitions II. T_II from specific heat and other data for polyisobutylene

Contributions of torsional braid analysis to T_u