Dilatometric study on the melting of polypropylene at elevated pressure

Leute, U.; Dollbopf, W.; Liska, E.

doi:10.1007/bf01383587

Cited by 31 publications

(29 citation statements)

References 25 publications

(19 reference statements)

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“…Moreover, results at low cooling rates are in accordance with results presented by Ito [8], Moldflow [14] and Zoller [22], results at elevated pressures are in accordance with results presented by He [6], Ito [10] and Leute [12] and results at high cooling rates show a resemblance with the work of Piccarolo [15]. The results moreover stress that standard techniques are not able to characterize the specific volume of semi-crystalline polymers.…”

Section: Influence Of Cooling Rate and Pressuresupporting

confidence: 90%

Influence of cooling rate on pVT‐data of semicrystalline polymers

Zuidema

Peters

Meijer

2001

J of Applied Polymer Sci

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For numerical simulations of the injection moulding process, an accurate description of the specific volume is needed to predict differential shrinkage during and after moulding, which causes thermally induced stresses and controls the dimensional accuracy and long term dimensional stability. For amorphous polymers, for which often it can be assumed that cooling rate dependence can be ignored, standard techniques enable measurements of the specific volume as a function of temperature and pressure. For semi-crystalline polymers the situation is more complicated since the specific volume depends strongly on the degree of crystallinity which itself depends on the thermo-mechanical history, i.e. temperature and pressure (for quiescent crystallization). This requires the use of a combined experimental-numerical technique to interpret the data and to determine the specific volume. Standard equipment can only be used at relatively low cooling rates. Since high cooling rates are present during injection moulding, improved experimental techniques must be designed. A setup based on the confining fluid technique is build, which can reach cooling rates up to 60[Ks −1 ] and pressures up to 20 · 10 6 [P a]. During an experiment, the specific volume is measured together with the temperature history and pressure. Using an accurate model to calculate the crystalline structure, together with a specific volume model which depends on this structure, enables the determination of model parameters. Comparing both the measurements and the model predictions, leads to the conclusion that modeling of the crystallization kinetics, results in accurate predictions of the specific volume.

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Section: Influence Of Cooling Rate and Pressuresupporting

confidence: 90%

Influence of cooling rate on pVT‐data of semicrystalline polymers

Zuidema

Peters

Meijer

2001

J of Applied Polymer Sci

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“…The pressure (usually elevated-positive) on the melting temperature of semicrystalline polymers was analysed in the past obtaining usually linear correlation between the change of melting temperature of crystals with the change of applied pressure. For isotactic polypropylene several such values were obtained (k ¼ dT m /dP): 0.338 K/MPa [45], 0.380 K/MPa [46], 0.395 K/ MPa [47]. Therefore, from the observed change of melting temperature (Fig.…”

Section: Samplementioning

confidence: 89%

Physical state of the amorphous phase of polypropylene-influence on thermo-mechanical properties

Krajenta

Różański

2015

Polymer

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“…The high pressure dilatometers, described in more detail in [1,2], are piston-cylinder devices of 6 mm and 22 mm diameter respectively. The former attains a pressure of about 2 kbar, measured in the sample, but not controlled.…”

Section: Apparatusmentioning

confidence: 99%

“…In this series one of our aims is to provide -besides accurate p VT-data -information about the influence of pressure on phase transitions. The first five papers dealt with PE [1,3,4], PEO [1], PP [1,2], poly(trans-l,4-butadiene) [5] and n-alkanes [4]. Now we have chosen poly(1-butene), (-CH2-CHC2Hs-),, subsequently called simply polybutene, as the topic of the present study for the two following reasons.…”

Section: Introductionmentioning

confidence: 98%

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High pressure dilatometry on polybutene-1

Leute

Dollhopf

1983

Colloid & Polymer Sci

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High pressure dilatometry is used to study the melting processes and the melt of isotactic polybutene-1. Evaluating a great number of isobaric V(T)-curves determined in the range of a few hundred bar the pressure dependence of the melting temperature is accurately determined for modifications I and II.Extrapolation to 1 bar yields dTJdp = 43.6 K/kbar and a heat of fusion AHm=8.0 kJ/ mol for modification I. The values for modification II are 21.4 and 6.9 resp. Up to 4.25 kbar data of melting temperature, volume, entropy and enthalpy as a function of pressure are reported and also the compressibility of the melt. Finally the relative thermodynamic stability of the different modifications is discussed.

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Dilatometric study on the melting of polypropylene at elevated pressure

Cited by 31 publications

References 25 publications

Influence of cooling rate on pVT‐data of semicrystalline polymers

Influence of cooling rate on pVT‐data of semicrystalline polymers

Physical state of the amorphous phase of polypropylene-influence on thermo-mechanical properties

High pressure dilatometry on polybutene-1

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