The dependence of the glass transition temperature on molecular weight for polyvinylchloride

Pezzin, G.; Zilio‐Grandi, F.; Sanmartín, Patricia

doi:10.1016/0014-3057(70)90038-8

Cited by 88 publications

(35 citation statements)

References 17 publications

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“…The glass transition temperature (Tg) was taken to be the temperature at the first change in slope of the enthalpy versus temperature curve obtained from a Dupont 900 differential scanning calorimeter at a heating rate of 5 K/minute. It was found to be 350 K, in good agreement with another measurement for PVC of equal 3~,, reported in [6].…”

Section: Introductionsupporting

confidence: 84%

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: Introductionsupporting

confidence: 84%

Longitudinal volume viscosity of poly (vinyl chloride)

Sanchez-Sancha¹,

Alemán²

1984

Rheol Acta

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“…A similar deviation has been found by other authors for poly(a-methylstyrene) [90] and poly(vinyl chloride) [91] with M n < 3 000. Our results contradict their observations.…”

Section: Glass Transition Temperature Of Uniform Polymerssupporting

confidence: 72%

Synthetic Uniform Polymers and Their Use for Understanding Fundamental Problems in Polymer Chemistry

Hatäda

Kitayama

Ute

et al. 2004

Macromol. Rapid Commun.

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Summary: A uniform polymer is a polymer composed of molecules that are uniform with respect to molecular weight and constitution. Besides natural uniform polymers such as nucleic acids and polypeptide, synthetic uniform polymers have been obtained by a variety of approaches. In particular, a combination of living polymerization and supercritical fluid chromatography (SFC) separation is one of the promising ways for the preparation of uniform polymers. End‐functionalized uniform polymers enabled us to prepare uniform polymer architectures such as block, graft, comb, and star polymers. Their use for understanding the fundamental problems in polymer chemistry is discussed; topics include crystallization of polymers, chain conformation in solution, and association of stereoregular polymers in solution.

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“…If we adopt the data of Quach and Simha, the end becomes far softer. Pezzin et al 20 suggested that in order to explain the behavior of 0 for many kinds of polymers, it would seem reasonable to take into account the molecular flexibility rather than the difference in the chain ends. This may be a reasonable suggestion, since the meaning of the 802 excess is relative to the entity of the chains.…”

Section: Resultsmentioning

confidence: 99%

Effect of Pressure on the Relation between Glass Transition Temperature and Molecular Weight for Monodispersed Polystyrenes

Toratani

Takamizawa

1994

Polym J

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ABSTRACT:The glass transition temperatures T• of monodispersed polystyrenes possessing different number-averaged molecular weights M. were determined by high pressure DTA of up to 500 MPa. The measurements were performed using samples glassified at a cooling rate of 20 K/min -1 under differing pressures. T• was satisfactorily fitted against P according to the Simon-type equation, which is usually applied to the relation between melting points and P. The linear relation of T• against M. -1 was found to hold even under high pressure. The slope of this relation increased from 0.98 x 10 5 K at atmospheric pressure to 1.19 x 10 5 K at 500 MPa. When the slope was analyzed by means of Bueche's model, the excess free volume of the chain ends decreased with increasing pressure and seemed to have an asymptotic value above 350 MPa, which was one-third of the value at atmospheric pressure.KEY WORDS Glass Transition Temperature / Molecular Weight Dependence/ Polystyrene/ Free Volume/ Pressure/ The linear relation of Tg against Mn -l has been established for many linear polymers, ever since the fundamental work by Fox and Flory1 was published. The relation is represented by:( 1) where Tgoo corresponds to the Tg of a polymer with infinite molecular weight. The slope K represents the characteristics of the polymer chain. For monodispersed polystyrene, two studies using DTA 2 and dilatometry 3 have been reported. Although these studies were based on different properties of heat capacity and volume, and although the freezing-in rate of glassification differed greatly, the K values which were obtained were nearly identical. The difference in Tgoo could be reasonably interpreted in terms of the freezing-in rate, based on a linear correlation between Tg and the logarithm of the glassification rate. 4 , 5 It has, moreover, been noted that an almost identical value of K was also reported for the molecular weight fractions of thermally polymerized polystyrenes. 1 It is concluded that K can be used as a reliable parameter reflecting chain character.Many studies on the pressure change of Tg have been carried out, partly because they would provide information which could shed light on the intrinsic nature of polymeric glass. However, it would seem that few studies on the pressure dependence of Khave been carried out. Using high pressure DT A, we have continued to study the relation of Tg vs. Mn -l under high pressure

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The dependence of the glass transition temperature on molecular weight for polyvinylchloride

Cited by 88 publications

References 17 publications

Longitudinal volume viscosity of poly (vinyl chloride)

Longitudinal volume viscosity of poly (vinyl chloride)

Synthetic Uniform Polymers and Their Use for Understanding Fundamental Problems in Polymer Chemistry

Effect of Pressure on the Relation between Glass Transition Temperature and Molecular Weight for Monodispersed Polystyrenes

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