Electrical and Flexural Properties of Copper and Graphite Filled Phenolic Resin Composites

2011 ◽  
Vol 418-420 ◽  
pp. 1044-1047
Author(s):  
Mi Dan Li ◽  
Huan Niu ◽  
Shou Bin Wei ◽  
Hong Yang
Keyword(s):  
Electrical Conductivity ◽  
Flexural Strength ◽  
Copper Powder ◽  
Phenolic Resin ◽  
Dendritic Structure ◽  
Principal Factor ◽  
Resin Composites ◽  
Mechanical Mixing ◽  
Copper Particles ◽  
Copper Powders

Composites made of phenolic resin filled with graphite platelets and copper particles (copper powder, copper fiber or both mixture), are fabricated by mechanical mixing. The electrical conductivity of composite composed of 30 wt% resin, 50 wt% graphite and 20 wt% copper powder is up to 600S/cm. The efficiency of copper powder is compared with copper fiber. The results show that copper powder is more effective than copper fiber in improving electrical conductivity. The particle shape is also a principal factor in influencing flexural strength. In this study, the flexural strength of composites tends to increase with decreasing the ratio of copper fiber/copper powder because the dendritic structure of copper powder enhances the probability of graphite platelets embedded in the dendritic arms, which in fact help to distribute the external load from matrix to copper powders.

Effect of Ratio of Copper Fiber/Copper Powder on Electrical Conductivity and Hardness of Copper/Graphite/Phenolic Resin Composites

2012 ◽  
Vol 457-458 ◽  
pp. 11-14
Author(s):  
Mi Dan Li ◽  
Shou Bin Wei ◽  
Huan Niu ◽  
Hong Yang
Keyword(s):  
Electrical Conductivity ◽  
Copper Powder ◽  
Particle Shape ◽  
Phenolic Resin ◽  
Copper Particle ◽  
Principal Factor ◽  
Resin Composites ◽  
Mechanical Mixing ◽  
Copper Particles ◽  
Sem Micrograph

Composites made of phenolic resin filled with graphite platelets and copper particles (copper powder, copper fiber or both mixture), are fabricated by mechanical mixing, followed by compression molding. SEM micrograph indicates that the fillers are homogenously dispersed in composite. The electrical conductivity of composite composed of 30 wt% resin, 50 wt% graphite and 20 wt% copper particle (10/10 wt/wt copper powder/copper fiber) is up to 65S/cm. The efficiency of copper fiber is compared with copper powder. The results show that copper fiber is more effective than copper powder in improving electrical conductivity for copper homogenously dispersed composite. The particle shape is also a principal factor in influencing hardness. In this study, the hardness of composites tends to increase with decreasing the ratio of copper fiber/copper powder.

Effects of the Mould Pressure and Mould Pressing Time on the Properties of Graphite/Phenolic Resin Composites

2013 ◽  
Vol 706-708 ◽  
pp. 95-98
Author(s):  
Mi Dan Li ◽  
Dong Mei Liu ◽  
Lu Lu Feng ◽  
Huan Niu ◽  
Yao Lu
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Flexural Strength ◽  
Polymer Matrix ◽  
Phenolic Resin ◽  
Polymer Matrix Composites ◽  
Resin Composites ◽  
Matrix Composites ◽  
Natural Graphite ◽  
Pressing Time

Polymer matrix composites made from phenolic resin are filled with natural graphite powders. They are fabricated by compression molding technique. The density, electrical conductivity and flexural strength of composite are analyzed to determine the influences of mould pressure and mould pressing time on the physical, electrical and mechanical properties of composite. It is found that the density, electrical conductivity and flexural strength of composites increased with increasing mould pressure. Under pressure of 40 MPa for 60 min, the density, electrical conductivity and flexural strength of composites were 1.85 g/cm3, 4.35  103 S/cm and 70 MPa, respectively. The decreased gaps could be the main reason for the increasing of density, electrical conductivity and flexural strength as mould pressure increases. The results also show that the density of composites increased with increasing mould pressing time.

Mechanical and Electrical Properties of Graphite/Carbon Fiber/Phenolic Resin Composite

2011 ◽  
Vol 418-420 ◽  
pp. 1452-1455
Author(s):  
Mi Dan Li ◽  
Dong Mei Liu
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Phenolic Resin ◽  
Resin Composite ◽  
Low Carbon ◽  
Mechanical Mixing ◽  
Mechanical And Electrical Properties ◽  
Resin Loading

Composites made of phenolic resin filled with natural graphite platelets and carbon fibers are fabricated by mechanical mixing, followed by compression molding. The flexural strength and electrical conductivity of composite are analyzed to determine the influence of phenolic resin and carbon fiber on mechanical and electrical properties. It is found that there is a marked dependence of the electrical conductivity and flexural strength on phenolic resin content. The electrical conductivity decreases and flexural strength increases with the increasing of phenolic resin loading. The presence of carbon fiber helps improve the flexural strength of composite such that 4 wt% CF increases the flexural strength of composite about 90%. However, an excess amount of carbon fiber reduces the flexural strength due to poor dispersion of carbon fiber in composite. The result also shows that the addition of carbon fiber exhibits a slight effect on the electrical conductivity of composite at low carbon fiber loadings.

Effects of Particle Size of Copper on the Electrical Property and Hardness of Copper/Graphite/Carbon Fiber/Phenolic Resin Composites

2013 ◽  
Vol 661 ◽  
pp. 120-123 ◽  
Author(s):  
Mi Dan Li ◽  
Yao Lu ◽  
Lu Lu Feng ◽  
Huan Niu ◽  
Ya Wen Kong
Keyword(s):  
Electrical Conductivity ◽  
Particle Size ◽  
Carbon Fibers ◽  
Considerable Increase ◽  
Phenolic Resin ◽  
Conductive Filler ◽  
Copper Particle ◽  
Natural Graphite ◽  
Copper Powders ◽  
Marked Dependence

Composites made from phenolic resin are filled with conductive filler mixtures containing copper powders, natural graphite powders and carbon fibers. They are fabricated by compression molding technique. The density, electrical conductivity and hardness of composite are analyzed to determine the influence of copper particle size on the physical, electrical and mechanical properties of composite. It is found that there is a marked dependence of the electrical conductivity and hardness on copper particle size. The hardness decreases with the decreasing of copper particle size. However the electrical conductivity increases with the decreasing of copper particle size. The decreasing of copper particle size from 75 µm to 48 µm promotes a considerable increase in electrical conductivity by about 427%. The increased continuous conductive metal networks could be the main reason for the increasing of electrical conductivity as copper particle size decreases. The results also show that composites containing copper particles of different sizes have the nearly same density.

Effects of the Mould Temperature on the Properties of Graphite/Carbon Fiber/Copper/Phenolic Resin Composites

2013 ◽  
Vol 470 ◽  
pp. 31-34
Author(s):  
Mi Dan Li ◽  
Yao Lu ◽  
Xin Guo
Keyword(s):  
Electrical Conductivity ◽  
Carbon Fiber ◽  
Phenolic Resin ◽  
Conductive Polymer ◽  
Resin Composites ◽  
Large Decrease ◽  
Mould Temperature ◽  
Compression Moulding ◽  
Natural Graphite ◽  
Conductive Polymer Composites

Natural graphite, carbon fiber and copper powder as fillers are incorporated into phenolic resin to fabricate conductive polymer composites by hot compression moulding. The effects of the preparing method and mould temperature on the density, electrical conductivity and hardness of composites are investigated. It is found that the density, electrical conductivity and hardness of composites increase as mould temperature increase from 150 °C to 180 °C. Up to 200 °C, the hardness of composite shows a large decrease. At 170 °C, the density, electrical conductivity and hardness of composites are 1.904 g/cm3, 3.43 × 103S/m and 54 HS, respectively. Oxidation action occurring in the phenolic resin could be the main reason for the large decrease of hardness as temperature increases up to 200 °C.

Effects of the Preparation Parameters on the Properties of Graphite/Carbon Fiber/Copper/Phenolic Resin Composites

2013 ◽  
Vol 483 ◽  
pp. 115-118
Author(s):  
Mi Dan Li ◽  
Huan Niu ◽  
Hong Yang
Keyword(s):  
Electrical Conductivity ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Phenolic Resin ◽  
Hot Compression ◽  
Curing Temperature ◽  
Compression Moulding ◽  
Natural Graphite ◽  
Skeleton Structure ◽  
Properties Of Composites

The polymer composites consist of phenolic resin, natural graphite, carbon fiber and copper powder, are fabricated by hot compression moulding or compression moulding followed by post-curing. The density, electrical conductivity and flexural strength of composites are analyzed to determine the influences of post-curing temperature and preparing method on the physical, electrical and mechanical properties of composites. It is found that the density, electrical conductivity and flexural strength of composites increase with increasing post-curing temperature for composites prepared by compression moulding followed by post-curing. The flexural strength is more strongly dependent on post-curing temperature. At 170 °C, the density, electrical conductivity and flexural strength of composites were 1.85 g/cm3, 2.94 × 103S/m and 40 MPa respectively. The cross-linking skeleton structure well established in the composites could be the main reason for the largely increasing of flexural strength as post-curing temperature increases. The results also show that the properties of composites prepared by hot compression moulding are higher than those of composites prepared by compression moulding followed by post-curing.

scholarly journals Electrical conductivity of poly (L lactic acid) and poly (3-hydroxybutyrate) composites filled with galvanostatically produced copper powder

2018 ◽  
Vol 72 (5) ◽  
pp. 285-292
Author(s):  
Zoran Jankovic ◽  
Miroslav Pavlovic ◽  
Marijana Pantovic-Pavlovic ◽  
Nebojsa Nikolic ◽  
Vladan Zecevic ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Lactic Acid ◽  
Copper Powder ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Dendritic Structure ◽  
Electrolytic Copper Powder ◽  
Particle Size And Morphology ◽  
Percolation Thresholds ◽  
Size And Morphology

This manuscript presents experimental studies of composite materials based on poly (L lactic acid) (PLLA) and poly (3-hydroxybutyrate) (PHB) matrices filled with electrolytic copper powder, having a very high dendritic structure. Volume fractions of the copper powder used as filler in all prepared composites were varied in the range 0.5-6.0 vol.%. Samples were prepared by hot moulding injection at 170 ?C. Influence of particle size and morphology, as well as the influence of matrix type on conductivity and percolation threshold of the obtained composites were examined. Characterization included: electrical conductivity measurements using AC impedance spectroscopy (IS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and Fourier-transform Infrared spectroscopy (FTIR). Presence of three-dimensional conductive pathways was confirmed. The obtained percolation thresholds of 2.83 vol.% for PLLA and 3.13 vol.% for PHB composites were measured, which is about three times lower than the ones stated in the literature for similar composites. This property is ascribed to different morphologies of the filler used in the present investigation.

scholarly journals Effect of Accelerated Aging on Some Mechanical Properties and Wear of Different Commercial Dental Resin Composites

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2769
Author(s):  
Jonne Oja ◽  
Lippo Lassila ◽  
Pekka K. Vallittu ◽  
Sufyan Garoushi
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Accelerated Aging ◽  
Wear Depth ◽  
Resin Composites ◽  
Expiration Date ◽  
Dental Resin ◽  
Hydrothermal Aging ◽  
Dental Resin Composites

The aim of current in vitro research was to determine the effect of hydrothermal accelerated aging on the mechanical properties and wear of different commercial dental resin composites (RCs). In addition, the effect of expiration date of the composite prior its use was also evaluated. Five commercially available RCs were studied: Conventional RCs (Filtek Supreme XTE, G-aenial Posterior, Denfil, and >3y expired Supreme XTE), bulk-fill RC (Filtek Bulk Fill), and short fiber-reinforced RC (everX Posterior). Three-point flexural test was used for determination of ultimate flexural strength (n = 8). A vickers indenter was used for testing surface microhardness. A wear test was conducted with 15,000 chewing cycles using a dual-axis chewing simulator. Wear pattern was analyzed by a three-dimensional (3D) noncontact optical profilometer. Degree of C=C bond conversion of monomers was determined by FTIR-spectrometry. The specimens were either dry stored for 48 h (37 °C) or boiled (100 °C) for 16 h before testing. Scanning electron microscopy (SEM) was used to evaluate the microstructure of each material. Data were analyzed using ANOVA (p = 0.05). Hydrothermal aging had no significant effects on the surface wear and microhardness of tested RCs (p > 0.05). While flexural strength significantly decreased after aging (p < 0.05), except for G-aenial Posterior, which showed no differences. The lowest average wear depth was found for Filtek Bulk Fill (29 µm) (p < 0.05), while everX Posterior and Denfil showed the highest wear depth values (40, 39 µm) in both conditions. Passing the expiration date for 40 months did not affect the flexural strength and wear of tested RC. SEM demonstrated a significant number of small pits on Denfil’s surface after aging. It was concluded that the effect of accelerated aging may have caused certain weakening of the RC of some brands, whereas no effect was found with one brand of RC. Thus, the accelerated aging appeared to be more dependent on material and tested material property.

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