Morphological, Electrical and Mechanical Properties of Ultrahigh Molecular Weight Polyethylene and Multi-wall Carbon Nanotube Composites Prepared in Decalin and Paraffin

Abstract

ABSTRACT:Ultrahigh molecular weight polyethylene (UHMWPE) and multi-wall carbon nanotube (MWNT) composites were prepared using either decalin or paraffin as solvent. Electrical conductivity measurements were performed for the original and heat-treated composites. The drastic increase in conductivity occurred at low MWNT content for the composite prepared in paraffin, while the conductivity of the composite prepared in decalin increased slightly up to 10 wt % MWNT content. Scanning electron microscopy observations revealed that the MWNTs within the composite prepared in decalin were covered by UHMWPE, and their average diameters were much greater than those of the original MWNTs, while the average diameter of the MWNTs within the composite prepared in paraffin was similar to the diameter of the original MWNTs. Such different morphology was found to be due to the different crystallization. The composites prepared in decalin had high drawability. Interestingly, the conductivities of the drawn (up to 50 times) and undrawn UHMWPE-MWNT composites were almost equal, independent of the MWNT content. As for the UHMWPE-MWNT composite (drawn up to 50 times) with 15 wt % MWNT content, the conductivity reached up to 10 À1 S/cm, and the modulus was higher than 50 GPa at ca. 25 C, indicating that a polymeric material with high modulus and relative high conductivity was successfully prepared.

Evaluation by tunneling effect for the temperature-dependent electric conductivity of polymer-carbon fiber composites with visco-elastic properties

“…[1][2][3][4][5][6][7][8][9][10][11][12] The conductivity increase up to 0 1C by the enhancement of electron transport has been attributed to two mechanisms, electron hopping [13][14][15][16][17] and electron tunneling. [2][3][4][5][18][19][20][21][22] Electron hopping is thought to occur by two mechanisms.…”

“…These major contradictions can be resolved by using a nonparabolic potential barrier (which is given by (11) later in the paper) and an estimated barrier width of 1.00 nm below 0 1C, which is a well-known rigorous value for metal-metal and metalsemiconductor junctions. 8,23 To further validate the application of the fluctuation-induced tunneling effect in polymer-filler composite systems using a nonparabolic potential barrier, we investigate another significant problem in using VRH to model insulating polymer semi-conductive filler (such as CF and carbon nanotube composites) composites. Mott's VRH analysis is completely appropriate for semiconducting phases such as TiO 2 doped by Co, Cr, Cd, Ce and Fe, 14 and the widespread application of VRH to doped semiconductors, amorphous conductors, glasses and conductive and semi-conductive polymers has also been successful.…”

Gelation mechanism of ultra-high-molecular-weight polyethylene (UHMWPE) chains in dispersion solutions containing multiwall carbon nanotubes (MWNTs) analyzed in terms of liquid-liquid phase separation

“…Figures 10a and b show the cross-section area of the composites after evaporating solvent, in which (a) and (b) are images of the composites before and after heat-treatment at ca. 150°C [22]. In comparison with the original MWNTs in Fig.…”

Effect of Heat Drawing Process on Mechanical Properties of Dry-Jet Wet Spun Fiber of Linear Low Density Polyethylene/Carbon Nanotube Composites

“…Because of high Young's modulus of 1-5 TPa and anisotropic properties, CNTs have been proposed as a material that can increase the elastic modulus and tensile strength of composite materials [20,21]. In addition, PE has been used as a matrix for preparing composites with CNTs using UHMWPE [22][23][24][25], HDPE [26,27], and LDPE [19,28] and as a thin film [29][30][31].…”