Carbon nanotubes induced nonisothermal crystallization of ethylene–vinyl acetate copolymer

Li, Sha-Ni; Li, Zhong‐Ming; Yang, Ming‐Bo; Hu, Zongqian; Xu, Xiaotong; Huang, Rui

doi:10.1016/j.matlet.2004.09.005

Cited by 68 publications

(30 citation statements)

References 23 publications

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“…One is that the tubes act as nucleating agents and may accelerate the non-isothermal crystallization of sPS. On the other hand, SWNT-PS may also adsorb sPS molecular segments and restrict the movement of chain segments, thereby making crystallization difficult [66]. Since the SWNTs surfacebound PS is compatible with sPS.…”

Section: The Activation Energy For Non-isothermal Crystallizationmentioning

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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Section: The Activation Energy For Non-isothermal Crystallizationmentioning

confidence: 99%

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

Xiong

Gao²,

Li³

2007

Express Polym. Lett.

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“…CNTs with high aspect ratios have attracted serious and extensive attention owing to their desire physical and mechanical properties [23][24][25]. Furthermore, CNTs develop heat and solvent resistance, crystallinity, microstructure, thermal expansion coefficient, and dielectric constant (DC) [26][27][28][29][30]. As a result of CNTs' reinforcing ability, it is verified efficiently for producing nanocomposites with excellent properties [31].…”

Section: Introductionmentioning

confidence: 99%

Properties and characterization of ethylene-vinyl acetate filled with carbon nanotube

2015

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Ethylene-vinyl acetate (EVA) containing carbon nanotubes (CNTs) were prepared by melt blending. Morphological observation showed well dispersion of CNTs in EVA. Effect of CNTs on crystallization of EVA was studied by differential scanning calorimetry (DSC). The beginning and maximum crystallization temperatures for CNT/EVA composite resulted 10 and 5°C higher than pure EVA, respectively, showing high nucleation capability of CNTs in EVA matrix. The morphologies were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM), whereas, flammability properties were assessed by thermogravimetric analysis (TGA), natural burning and cone calorimetry. It was resulted that when nanodimensional material was not well dispersed, degradation products were not changed significantly. Unlike, CNT/EVA nanocomposites gave reasonably good reductions in peak heat release even when well nano-dispersed has not been obtained due to formation of low permeable char containing graphitic carbon. It was noticeable that CNT addition to EVA reduced surface cracks of chars which improved barrier resistance to evolution of flammable volatiles and oxygen access to condensed phase. The CNTs declined heat release rates and mass loss rate by 50-60 %, prolonged combustion time to two times in CNT/EVA samples. The TGA data also displayed that CNTs increased thermal degradation temperatures and final & Maziyar Sabet charred residues of CNT/EVA samples. The experimental observations from the torque, morphological evolution tests, and SEM resulted that CNTs are utilized for (1) increase of melt viscosity due to network structure formation of CNTs in the EVA matrix; (2) the enhancement of thermoxidation stability as a result of the CNTs' mechanical strength and integrity of the charred layers in the CNT/EVA nanocomposites; (3) the formation of compact charred layers promoted by CNTs acted as heat barrier and thermal insulation.

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“…In evaluating our SWNT-polymer nanocomposite systems, we also find evidence of nanotube induced polymer crystallization. It is well known that nanotubes are one of the most effective nucleation agents for the heterogeneous crystallization of polymers, particularly for crystalline and semicrystalline polymers [17][18][19][20]. Li et al demonstrated, for example, that selected polyethylene (PE) oligomers at a low molecular weight, 800 g/mol, demonstrated evidence of crystallization at nanotube sites [17].…”

Section: Introductionmentioning

confidence: 99%

Viscosity and Morphology Modification of Length Sorted Single-Walled Carbon Nanotubes in PIB Matrices

Huang

Simien

et al. 2017

Journal of Nanomaterials

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This work evaluates the effectiveness of nanoscale particulates in producing non-Einstein-like responses in polymer matrices, to reduce their negative effects in low shear rate processing. This is of value to material processing applications which encompass extrusion, flow into cold mold, and generalized processing of nanocomposites. Through control and understanding of the structure processing relationships entailed through nanoscale additive materials, we begin to manage dispersion characteristics for more reliable and defect-free product development. In pursuit of identifying system characteristics that produce non-Einstein-like responses we isolate and characterize homogenous fractions of single-walled carbon nanotubes (SWNTs) with singular lengths. This enables the definition of a well-defined nanoscale particulate phase, within the polymer matrices. The effect of nanotube length and weight fraction on the polyisobutylene (PIB) matrices was evaluated with thermal and rheological testing. Our findings show that the viscosity of the produced nanocomposite systems has a length dependence and does not demonstrate the expected monotonous increases in the viscosity with an increase in weight fraction of nanotube additive within the matrix, demonstrating a non-Einstein-like viscosity response. Furthermore, we demonstrate length dependent crystallization in the studied systems, as an intermediate length nanotube initiates crystallization of polyisobutylene (PIB) affecting viscosity and mechanical properties.

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Carbon nanotubes induced nonisothermal crystallization of ethylene–vinyl acetate copolymer

Cited by 68 publications

References 23 publications

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

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

Properties and characterization of ethylene-vinyl acetate filled with carbon nanotube

Viscosity and Morphology Modification of Length Sorted Single-Walled Carbon Nanotubes in PIB Matrices

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