Transcrystallinity effects in thin polymer films. Experimental and theoretical approach

Billon, Noëlle; Magnet, C.; Haudin, Jean‐Marc; Lefebvre, Denis

doi:10.1007/bf00659278

Cited by 69 publications

(83 citation statements)

References 34 publications

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“…3- 5 The ture. 8,12,13 On the other hand, although it has been specific morphology of the polymer in the transfound that the glass fiber increases the nucleation crystalline zone is expected to influence the adhedensity, 9 the existence of a transcrystalline zone sion at the interface, due to an increased nucleation density as well as the mechanical properties was not proved by microscopic investigations.…”

Section: Introductionmentioning

confidence: 99%

Isothermal crystallization of iPP in model glass-fiber composites

Janevski¹,

Bogoeva‐Gaceva²

1998

J. Appl. Polym. Sci.

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Isothermal crystallization of iPP in model glass-fiber composites is studied by DSC, and the basic energetic parameters of crystallization are determined. Unsized untreated and thermally treated glass fibers are used in model composites to determine the role of the surface on nucleation and crystallization processes. Thermally treated glass fibers are found to exhibit a predominant nucleating effect as compared to unsized untreated ones, and the crystallization proceeds faster, resulting in lower values for the halftime of crystallization (10-120 s). The energy of formation of a nuclei of critical dimensions at a given T c is also lower, and it decreases as the content of the fibers in the composite increases. The surface free energy of folding, s e Å 140 1 10 03 J/m 2 , was determined for iPP in the composite containing 50% glass fibers, while for pure iPP, s e Å 170 1 10 03 J/m 2 was found.

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Section: Introductionmentioning

confidence: 99%

Isothermal crystallization of iPP in model glass-fiber composites

Janevski¹,

Bogoeva‐Gaceva²

1998

J. Appl. Polym. Sci.

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“…Some of its particular effects have been discussed in previous articles. 3,12,13 The crystallization traces and, accordingly, any data deduced from them depend on the cooling rate, the surface nucleation, the bulk nucleation, and the thickness of the sample. A theoretical model was developed 12 and applied to this technique to explain some experimental observations.…”

Section: Introductionmentioning

confidence: 99%

“…3,12,13 The crystallization traces and, accordingly, any data deduced from them depend on the cooling rate, the surface nucleation, the bulk nucleation, and the thickness of the sample. A theoretical model was developed 12 and applied to this technique to explain some experimental observations. 12,13 Unfortunately, this model, when expressed in its most general form, remains difficult to use for the interpretation of experimental results and for the extraction of intrinsic characteristics of the polymer.…”

Section: Introductionmentioning

confidence: 99%

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Transcrystallinity effects in high‐density polyethylene. II. Determination of kinetics parameters

Billon

Henaff

Haudin

2002

J of Applied Polymer Sci

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International audienceTranscrystallinity may occur during differential scanning calorimetry analysis at the surfaces of the samples. In such a case, measurements may be unsuitable. We propose simple methods for the determination of intrinsic crystallization data that are accurate for the polymer and for the determination of the nucleating ability of the surfaces. These methods are based on the experimental analysis of the crystallization of samples with different and calibrated thicknesses during experiments at different constant cooling rates. Analysis of thin samples allowed the characterization of transcrystallinity, whereas analysis of at least three samples of different thicknesses allowed us to determine the true crystallization kinetics of the bulk material. These two techniques were independent of each other and were successfully applied to the case of a high-density polyethylene. The determinations were verified with simple analytical models. A further extension could be the study of the nucleating ability of different substrates

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“…Except the coefficient of thermal conductivity, physical parameters of the polymeric material and kinetic parameters of crystallization show only weak effects compared to cooling conditions. developed to predict the morphology evolution during isothermal crystallization [14][15][16][17] . For non-isothermal crystallization, Chan and Isayev 10) reported experimental results of the crystallinity distribution throughout the thickness direction of a quenched slab.…”

Section: Introductionmentioning

confidence: 99%

FEM simulation of nonisothermal crystallization, 1 Crystallinity distribution on 2 D space

Yan¹,

Jiang

2000

Macromol. Theory Simul.

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This work employs the relaxed Stefan model and Nakamura crystallization kinetics to describe the nonisothermal crystallization process of polymeric materials by finite element discretization method (FEM) simulation, giving the evolution of crystallinity distribution on 2 D space. Numerical results show that the final crystallinity and its distribution are mainly dependent on the cooling rate. Crystallinity decreases with increasing cooling rate, but the influence is negligible as long as the cooling rate is below a critical value (ca. 30°C·min–1 for poly(ethylene terephthalate) (PET)). If the cooling rate is higher than this critical one, crystallinity drops sharply. It is also concluded that the crystallization behavior of polymeric samples in a mild cooling medium is quite different from that in a strong cooling medium. In the first case (for example, in silicon oil), crystallinity of the article is relatively high and its distribution is fairly uniform. During the initial short period, the crystallinity on the surface is higher than that on the inside. Crystallinity increases slowly with time, and finally, the crystallinity of the internal part exceeds the crystallinity on the surface. In the second case (for instance, in water), crystallinity is relatively low, and there is a serious gradient of crystallinity. The crystallinity on the surface reaches a very low equilibrium value in a short time and changes little afterwards. Although the crystallinity of the inside part can be improved by changing the shape of the polymeric article, the crystallinity on the surface essentially remains constant, which leads to a significant gradient. Geometrical shape and dimension of the article are also important to the crystallinity and its distribution, and the ratio of surface area to volume can be used as a rough index to estimate the shape/dimension influence on crystallinity. Except the coefficient of thermal conductivity, physical parameters of the polymeric material and kinetic parameters of crystallization show only weak effects compared to cooling conditions.

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Transcrystallinity effects in thin polymer films. Experimental and theoretical approach

Cited by 69 publications

References 34 publications

Isothermal crystallization of iPP in model glass-fiber composites

Isothermal crystallization of iPP in model glass-fiber composites

Transcrystallinity effects in high‐density polyethylene. II. Determination of kinetics parameters

FEM simulation of nonisothermal crystallization, 1 Crystallinity distribution on 2 D space

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