Non-isothermal crystallization of polymers

Lorenzo, Maria Laura Di; Silvestre, Clara

doi:10.1016/s0079-6700(99)00019-2

Cited by 508 publications

(415 citation statements)

References 107 publications

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“…To quantitatively describe the evolution of crystallinity during non-isothermal crystallization, a number of models have been proposed in the literature [30]. The most common approach is that proposed by Lui et al [31] who combined the Avrami and Ozawa models [32][33][34][35] to analyze the non-isothermal crystallization kinetics.…”

Section: Lui Modelmentioning

confidence: 99%

Non-Isothermal Cold-Crystallization Behavior and Kinetics of Poly(l-Lactic Acid)/WS2 Inorganic Nanotube Nanocomposites

2015

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Abstract:In order to accelerate the crystallization of poly(L-lactic acid) (PLLA) biopolymer and enhance its crystallizability, biocompatible and environmentally friendly tungsten disulphide inorganic nanotubes (INT-WS 2 ) were introduced into the polymer matrix. The non-isothermal cold-crystallization and subsequent melting behaviour of pure PLLA and PLLA/INT-WS 2 nanocomposites were investigated in detail by varying both the heating rate and INT-WS 2 loading. The kinetic parameters of the cold-crystallization process of PLLA chains under confined conditions, successfully described using Liu model, shows that the addition of INT-WS 2 significantly increased the crystallization rate and reduced the total cold-crystallinity of PLLA, while the crystallization mechanism and crystal structure of PLLA remained unchanged in spite of the INT-WS 2 loading. Similarly, the final crystallinity and melting behaviour of PLLA were controlled by both the incorporation INT-WS 2 and variation of the heating rate. The differential isoconversional method of Friedman was applied to estimate the dependence of the effective activation energy on the relative crystallinity and temperature for PLLA and PLLA/INT-WS 2 . On the other hand, the double-melting peaks, mainly derived from melting-recrystallization-melting processes upon heating, and their dynamic behaviour is coherent with a remarkable nucleation-promoting effect of INT-WS 2 involved in accelerating the cold-crystallization of PLLA. These observations have considerable practical significance for the future sustainable, economic and effective technological utilisation of PLLA, as it will enable the development of novel melt-processable biopolymer nanocomposite materials.

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Section: Lui Modelmentioning

confidence: 99%

Non-Isothermal Cold-Crystallization Behavior and Kinetics of Poly(l-Lactic Acid)/WS2 Inorganic Nanotube Nanocomposites

2015

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“…The experimental facts indicate that the Ozawa equation is not suitable for describing the kinetics in the non-isothermal crystallization process of sPS and its composites. This result may arise due to the secondary crystallization and the dependence of the fold length on temperature for sPS, as well as instantaneous nucleation, rapid impingement and possibly secondary crystallization for the nanocomposites [55][56][57].…”

Section: Non-isothermal Crystallization Behaviormentioning

confidence: 99%

Non-isothermal crystallization kinetics of syndiotactic polystyrene polystyrene functionalized SWNTs nanocomposites

Xiong

Gao²,

Li³

2007

Express Polym. Lett.

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Carbon nanotubes (CNTs) are unique nanostructured materials with remarkable physical, mechanical and electronic properties [1][2][3][4]. These properties make them attractive for applications in many scientific and technological fields such as electronic structures [5], polymer composites [6], and biological systems [7]. Among these potential applications, the prospect of obtaining high-performance CNT based polymeric nanocomposites has attracted the efforts of researchers in both academia and industry [8]. The combination of organic polymer components with CNT fillers in a single material has extraordinary significance for the development of advanced materials with remarkable mechanical, electrical, thermal and multifunctional properties [9][10][11][12]. Moreover, polymer/CNT nanocomposites challenge traditional filled polymers (loadings of 20 wt% or more) in many of these areas by providing similar physical enhancements but with as little as about 1 wt% addition of dispersed nanotubes [13]. Previous CNT based polymeric nanocomposites reports include increased modulus, impact strength, heat distortion temperature, and barrier properties with decreased thermal expansivity [14][15][16]. In addition, these nanocomposites are finding potential applications such as electrostatically dissipative materials and aerospace materials [17]. Currently, several processing methods, including melt mixing, solution process and in-situ polymerization [18][19][20] Abstract. Non-isothermal crystallization kinetics were characterized by using differential scanning calorimetry (DSC) analysis on neat semicrystalline syndiotactic polystyrene (sPS) and its nanocomposites with polystyrene (PS) functionalized full-length single walled carbon nanotubes (SWNT-PS), which was prepared by copper (I) catalyzed click coupling of alkyne-decorated SWNTs with well-defined, azide-terminated PS. The crystallization behavior of neat sPS polymer was compared to its SWNT based nanocomposites. The results suggested that the non-isothermal crystallization behavior of sPS/SWNT-PS nanocomposites depended significantly on the SWNT-PS contents and cooling rate. The incorporation of SWNT-PS caused a change in the mechanism of nucleation and the crystal growth of sPS crystallites, this effect being more significant at lower SWNT-PS content. Combined Avrami and Ozawa analysis was found to be effective in describing the non-isothermal crystallization of the neat sPS and its nanocomposites. The activation energy of sPS determined from nonisothermal data decreased with the presence of small quantity of SWNT-PS in the nanocomposites and then increased with increasing SWNT-PS contents.

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“…PET is the best example of polymer where cold-crystallization occurs. Although of enormous importance from a scientific point of view, cold-crystallization has not played an important role in the technological application of polymers, since polymer processing occurs in the melt phase and it is the size, dimension and distribution of the crystallites developed upon cooling from the melt that determine the final properties of the material [1]. A number of papers have been published on this topic, so they were mainly concerned with the kinetic aspects of the process and the way it is influenced by the molecular weight, chain orientation, aging below and above T g and by exposure to the organic solvents [30].…”

Section: Cold-crystallizationmentioning

confidence: 99%

“…The subject of polymer crystallization has been of great interest for several decades due to the complex phenomena usually taking place, as well as its industrial importance [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Crystallization of Polypropylene: Application of Differential Scanning Calorimetry Part I. Isothermal and Non-Isothermal Crystallization

Raka¹,

Bogoeva‐Gaceva²

2017

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Non-isothermal crystallization of polymers

Cited by 508 publications

References 107 publications

Non-Isothermal Cold-Crystallization Behavior and Kinetics of Poly(l-Lactic Acid)/WS2 Inorganic Nanotube Nanocomposites

Non-Isothermal Cold-Crystallization Behavior and Kinetics of Poly(l-Lactic Acid)/WS2 Inorganic Nanotube Nanocomposites

Non-isothermal crystallization kinetics of syndiotactic polystyrene polystyrene functionalized SWNTs nanocomposites

Crystallization of Polypropylene: Application of Differential Scanning Calorimetry Part I. Isothermal and Non-Isothermal Crystallization

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