Determination of percolation threshold and electrical conductivity of polyvinylidene fluoride (PVDF)/short carbon fiber (SCF) composites: effect of SCF aspect ratio

2016 ◽  
Vol 66 (4) ◽  
pp. 573-582 ◽  
Author(s):  
Ranvijai Ram ◽  
Mostafizur Rahaman ◽  
Ali Aldalbahi ◽  
Dipak Khastgir
Keyword(s):  
Electrical Conductivity ◽  
Carbon Fiber ◽  
Aspect Ratio ◽  
Percolation Threshold ◽  
Polyvinylidene Fluoride ◽  
Short Carbon Fiber ◽  
Short Carbon

Electrical and Mechanical Properties of Short-Carbon-Fiber Reinforced Polymerized Cyclic Butylene Terephthalate Composites

2015 ◽  
Vol 813 ◽  
pp. 278-284
Author(s):  
Bin Yang ◽  
Ji Feng Zhang ◽  
Lu Zhang ◽  
Shao Hua Fan ◽  
Li Min Zhou
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Percolation Threshold ◽  
Bending Test ◽  
Material System ◽  
Melt Mixing ◽  
Butylene Terephthalate ◽  
Short Carbon Fiber ◽  
Cyclic Butylene Terephthalate ◽  
Short Carbon

Polymerized cyclic butylene terephthalate (pCBT) resin casts filled with short carbon fibers were prepared by the melt-mixing approach. The electrical conductivity of short-carbon-fiber (SCF) reinforced thermoplastic pCBT resin casts were investigated with a special attention paid to the properties in the percolation threshold region and the mechanical properties of the composites were also studied. The percolation threshold value of the novel material system was determined which was also verified by SEM images and the thermoelectric behavior of the specimens. Even though the electrical properties of SCF/pCBT composites enhanced significantly, the material becomes more brittle than neat pCBT and all the specimens appear brittle fracture during the mechanical test. Moreover, fiber pull-out is the main damage form in three-point-bending test.

Electrical Conductivity of Barium-Ferrite-Vulcanized Polychloroprene Filled with Short Carbon Fiber

1992 ◽  
Vol 65 (1) ◽  
pp. 7-23 ◽  
Author(s):  
P. B. Jana ◽  
S. K. De ◽  
S. Chaudhuri ◽  
A. K. Pal
Keyword(s):  
Carbon Fiber ◽  
Aspect Ratio ◽  
Carrier Concentration ◽  
Barium Ferrite ◽  
Volume Resistivity ◽  
Positive Temperature ◽  
Short Carbon Fiber ◽  
Fiber Aspect Ratio ◽  
Mixing Method ◽  
Short Carbon

Abstract Short-carbon-fiber-filled polychloroprene composites, prepared by mill-mixing and cement-mixing methods were vulcanized by barium ferrite. The effects of concentration and aspect ratio (L/D) of short carbon fiber on volume resistivity have been studied. Composites prepared by the cement mixing method having high fiber aspect ratio (L/D 100) show higher hardness and modulus accompanied by lower elongation and volume resistivity than the composites prepared by the mill mixing method, which give low fiber aspect ratio (L/D 25). Experimental values of volume resistivity agreed reasonably well with the calculated values from the theory based on probability of formation of conductive network. The temperature dependence of volume resistivity of the composite shows a positive temperature coefficient. The shape of the hysteresis loop, observed during the heating and cooling cycle in the variation of volume resistivity with temperature, depends on the concentration and aspect ratio of short carbon fiber. Hall-effect studies indicate that increase in fiber concentration and aspect ratio in the composites causes increase in carrier concentration and decrease in mobility of the carriers. With increase in temperature, both conductivity and carrier concentration decrease and mobility of the carriers increases.

Properties of Graphite Matrix Composite Bipolar Plate Reinforced by Short Carbon Fiber

2011 ◽  
Vol 109 ◽  
pp. 105-109 ◽  
Author(s):  
Yan Ming Wang ◽  
Wei Qiang Wang ◽  
Ai Ju Li
Keyword(s):  
Electrical Conductivity ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Fracture Mode ◽  
Bipolar Plate ◽  
Resin Content ◽  
Graphite Composite ◽  
Short Carbon Fiber ◽  
Graphite Matrix ◽  
Short Carbon

Short carbon fiber is used to reinforce phenol formaldehyde (PF) resin/graphite composite. With carbon fiber by thick nitric acid liquid-phase oxidative surface treatment (TNALPOST) and its content 3.wt%~ 4.wt%, the composite flexural strength is increased highly and electrical conductivity is also increased on some degree. To PF resin/graphite matrix material without carbon fiber added, if PF resin content is 15.wt%, its flexural strength is 49.0MPa and electrical conductivity is 111S/cm. But with adding carbon fiber by TNALPOST and the same PF resin content , the composite flexural strength and electrical conductivity approach 68MPa、122S/cm respectively, both mechanical property and electrical property satisfy the requirement of USA Department of Energy on carbon filler/polymer composite bipolar plate. The PF resin/graphite composite without carbon fiber added presents brittle fracture mode, but with carbon fiber added, it presents ductile fracture mode. According to the fracture morphology by scanning electron microscopy, carbon fiber and matrix is on relatively weak boundary bonding state accompanied by fiber de-bounding、sliding、pulling-out and bridge-making to crack, they are main factors contributed to improving composite toughness.

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