Study on the Mechanical and Electrical Properties and Creep Behaviour of Carbon Fiber Nano-Composites

In recent years, the influence of surface modification of carbon nanotubes (CNTs ) on CNT’s dispersion among epoxy resin, mechanical properties and electrical conductivities of CNTs has been observed. On account of above-mentioned effects, that CNTs treated with oxidizing in organic acids, a kind of surface modification, generates functional groups on the surface of CNTs is a major investigation in this study to enhance mechanical properties and electrical conductivities of CNTs. In this study, CNTs dispersed among epoxy resin well by adopting ultrasonication method and then the nano-prepreg was fabricated by mixing CNTs/Epoxy resin into carbon fiber. The influence of the different proportion contents of CNTs added into Epoxy resin on mechanical properties and electrical conductivities of composites is investigated. The strength of material tested under different circumstance is also observed. Furthermore, the creep behavior of carbon fiber/epoxy resin thermosetting composites tested under different circumstance and stress is also concerned to be analyzed.

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Mechanical Properties and Creep Behavior of Carbon Fiber Nano-Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.233-235.2794 ◽

2011 ◽

Vol 233-235 ◽

pp. 2794-2799

Author(s):

Yi Luen Li ◽

Wei Jen Chen ◽

Ming Yuan Shen ◽

Chin Lung Chiang ◽

Ming Chuen Yip

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Surface Modification ◽

Carbon Fiber ◽

Epoxy Resin ◽

Creep Behavior ◽

Primary Creep ◽

Sem Image ◽

Creep Stress ◽

Electrical Conductivities

Recently, it has been observed that surface modification of carbon nanotubes（CNTs）influences on CNT’s distribution among epoxy resin and affects the mechanical properties and electrical conductivities of CNTs. Owing to above-mentioned effects, carbon nanotubes treated with oxidizing in organic acids, a kind of surface modification, generates functional groups on the surface of CNTs taht is a major investigation in this study to enhance mechanical properties and electrical conductivities of CNTs. The influence of the different proportion contents of CNTs added into epoxy resin on mechanical properties and electrical conductivities of composites was investigated, and strength of material tested under different temperature environments was observed. Moreover, the creep behavior of carbon fiber（CF）/epoxy resin thermosetting composites tested under different temperature and stress were also concerned to be analyzed. The resulting creep behavior consists of only two stages, including primary creep and steady-state creep. The effects of creep stress, creep time, different humidity treatment on the various temperature creep of composites containing different proportion contents of CNTs were investigated. It is believed that the increased creep strains can be attributed to higher applied stresses, longer creep times, higher humidity, higher temperature and lower hardnesses. The test results also exhibit that mechanical strength and electrical conductivity increase with the increase of CNTs content added into composites. In the influence of temperature effect on specimen, because of different coefficient of expansion among matrix, fiber and CNTs, the overexpansion of matrix caused by high temperature results in crack occurred among matrix. From observation of the fracture surface by SEM image, the debonding occurs and longitudinal fibers are pulled out due to poor interfacial bonding of fiber and matrix, which also results in entire strength degeneration.

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Study on the Mechanical Properties and Creep Behaviour of Carbon Fiber Nano-Composites

MRS Proceedings ◽

10.1557/opl.2011.146 ◽

2011 ◽

Vol 1312 ◽

Author(s):

Yi-Luen LI ◽

Wei-Jen Chen ◽

Chin-Lung Chiang ◽

Ming-Chuen Yip

Keyword(s):

Mechanical Properties ◽

Carbon Fiber ◽

Epoxy Resin ◽

Creep Behaviour ◽

Primary Creep ◽

Sem Image ◽

Electrical Conductivities ◽

The Matrix ◽

Different Temperatures ◽

Creep Time

ABSTRACTThe surface modification of carbon nanotubes（CNTs）has been recently observed to influence the distribution of CNTs in epoxy resin and the mechanical properties and electrical conductivities of these CNTs. Accordingly, the treatment of CNTs with organic acids to oxidize them generates functional groups on the surface of CNTs. This investigation studies the consequent enhancement of the mechanical properties and electrical conductivities of CNTs. The influence of adding various proportions of CNTs to the epoxy resin on the mechanical properties and electrical conductivities of the composites thus formed is investigated, and the strength of the material is tested at different temperatures. Moreover, the creep behavior of carbon fiber （CF）/epoxy resin thermosetting composites was tested and analyzed at different temperatures and stresses. The creep exhibits only two stages- primary creep and steady-state creep. The effects of creep stress, creep time, and humidity on the creep of composites that contain various proportion of CNTs were investigated at various temperatures.Creep strain is believed to increase with applied stress, creep time, humidity, and temperature. It also increases as hardness decrease. The test results also indicate that mechanical strength and electrical conductivity increase with the amount of CNTs added to the composites. Different coefficients of expansion of the matrix, fiber and CNTs, are such that overexpansion of the matrix at high temperature results in cracking in it. An SEM image of the fracture surface reveals debonding and the pulling out of longitudinal fibers because of poor interfacial bonding between fiber and matrix, which reduce overall strength.

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