The rheological behavior and thermal conductivity of melt-compounded polycarbonate/vapor-grown carbon fiber composites

Nithikarnjanatharn, Jittiwat; Ueda, Hisai; Tanoue, Shuichi; Uematsu, Hideyuki; Iemoto, Yoshiyuki

doi:10.1038/pj.2011.149

Cited by 9 publications

(3 citation statements)

References 32 publications

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“…We reported that the number average length of CF decreased by 60-70 percent when mixed with a co-rotating twin screw extruder, irrespective of CF content. 49 When it was assumed that the average length of CF decreased by 60-70 percent, the values of TR calculated from equation 1were 3.8-5.1. Therefore, CF may be well dispersed in the PE matrix, given that the experimental data approximately coincided with Batchelor's theoretical equation.…”

Section: Uniaxial Elongational Viscositymentioning

confidence: 99%

Effect of carbon fiber on the capillary extrusion behaviors of high-density polyethylene

Uematsu

Horisawa

Horikida

et al. 2012

Polym J

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The capillary extrusion behaviors of high-density polyethylene (PE) containing carbon fibers (CF) were investigated from a viewpoint of their rheological properties. For values of CF content ranging from 0 to 5 wt%, the oscillatory moduli of PE slightly increased with CF content. Transient shear flow measurements showed that the steady shear viscosity and first normal stress difference of PE also slightly increased with the addition of CF. Conversely, the strain hardening behaviors of PE were suppressed by CF addition. It was found that CF becomes well dispersed in the PE matrix and that the elongation of the PE chain can be prevented by the presence of CF. The swell ratio of PE, which is the ratio of the diameters of the extrudate and the die, decreased with CF. Using a wide entrance angle die, PE/CF exhibited helical distortion at a higher output rate than that of PE. Using a narrow entrance angle die, sharkskin failure was observed in PE/CF at a higher output rate than in PE, although the helical distortion of PE was inhibited by CF. We discuss the origin of the helical distortion as an effect of CF on the swell behavior and the flow instabilities of PE in reference to the rheological behavior.

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Section: Uniaxial Elongational Viscositymentioning

confidence: 99%

Effect of carbon fiber on the capillary extrusion behaviors of high-density polyethylene

Uematsu

Horisawa

Horikida

et al. 2012

Polym J

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“…It was reported that the length of the fiber was decreased using twin screw extruder [10]. To confirm the length of fibrous fillers after compounding, the length of fibrous fillers was evaluated.…”

Section: Origin Of Swell Decrease By Presence Of Fillermentioning

confidence: 99%

Origin of Reduction in Extrudate Swell of Molten Polymer by Adding of Rigid Fillers

2018

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The effect of rigid fillers having various shapes and sizes on the extrudate swell of molten polymer was investigated. High-density polyethylene (PE) was used as the matrix polymer to quantify the swell behaviors. The shear viscosity of PE was almost unaffected via the addition of any fillers. However, the swell ratio decreased in the presence of fillers. In particular, the swell ratio was decreased by increasing the aspect ratio of fibrous fillers and the suppression of the swell hardly changed with the size of particle fillers. The first normal stress difference that can quantify the extension of polymer chains under shear flow, changed negligibly in spite of the presence of particle and fibrous fillers. On the other hand, the orientation of fibrous fillers along flow direction was clearly demonstrated based on their dispersion state in the extrudate. The swell of molten polymer containing fillers was greatly reduced by increasing the aspect ratio of fibrous fillers, because the constriction of the oriented polymer chains at die exit was suppressed by sticking on the surface of oriented fibrous fillers.

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“…Gojny et al [8] studied the thermal conductivity of epoxy resin as a matrix and multi-walled carbon nanotubes and single-walled carbon nanotubes as fillers. Jittiwat et al [9] studied the thermal conductivity of polycarbonate as a matrix and carbon fibers with two aspect ratios of 40 µm and 100 µm as fillers. It was found that fillers with larger aspect ratios were more effective in improving the thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

Performance Study of Diamond Powder-Filled Sodium Silicate-Based Thermal Conductive Adhesives

et al. 2023

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With the development of miniaturized, highly integrated, and multifunctional electronic devices, the heat flow per unit area has increased dramatically, making heat dissipation a bottleneck in the development of the electronics industry. The purpose of this study is to develop a new inorganic thermal conductive adhesive to overcome the contradiction between the thermal conductivity and mechanical properties of organic thermal conductive adhesives. In this study, an inorganic matrix material, sodium silicate, was used, and diamond powder was modified to become a thermal conductive filler. The influence of the content of diamond powder on the thermal conductive adhesive properties was studied through systematic characterization and testing. In the experiment, diamond powder modified by 3-aminopropyltriethoxysilane coupling agent was selected as the thermal conductive filler and filled into a sodium silicate matrix with a mass fraction of 34% to prepare a series of inorganic thermal conductive adhesives. The thermal conductivity of the diamond powder and its content on the thermal conductivity of the adhesive were studied by testing the thermal conductivity and taking SEM photos. In addition, X-ray diffraction, infrared spectroscopy, and EDS testing were used to analyze the composition of the modified diamond powder surface. Through the study of diamond content, it was found that as the diamond content gradually increases, the adhesive performance of the thermal conductive adhesive first increases and then decreases. The best adhesive performance was achieved when the diamond mass fraction was 60%, with a tensile shear strength of 1.83 MPa. As the diamond content increased, the thermal conductivity of the thermal conductive adhesive first increased and then decreased. The best thermal conductivity was achieved when the diamond mass fraction was 50%, with a thermal conductivity coefficient of 10.32 W/(m·K). The best adhesive performance and thermal conductivity were achieved when the diamond mass fraction was between 50% and 60%. The inorganic thermal conductive adhesive system based on sodium silicate and diamond proposed in this study has outstanding comprehensive performance and is a promising new thermal conductive material that can replace organic thermal conductive adhesives. The results of this study provide new ideas and methods for the development of inorganic thermal conductive adhesives and are expected to promote the application and development of inorganic thermal conductive materials.

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The rheological behavior and thermal conductivity of melt-compounded polycarbonate/vapor-grown carbon fiber composites

Cited by 9 publications

References 32 publications

Effect of carbon fiber on the capillary extrusion behaviors of high-density polyethylene

Effect of carbon fiber on the capillary extrusion behaviors of high-density polyethylene

Origin of Reduction in Extrudate Swell of Molten Polymer by Adding of Rigid Fillers

Performance Study of Diamond Powder-Filled Sodium Silicate-Based Thermal Conductive Adhesives

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