Mechanical and Thermal Properties of Al2O3-Filled Epoxy Composites

The paper presents studies of influences of platelet-shape alumina content on the morphology, mechanical and thermal properties of Al2O3/epoxy composites. The alumina particles were pre-treated with surface modifier, and its addition contents were ranged from 17 to 40vol.%. It was found that tensile strength and thermal conductivity increased with the increase of the alumina contents. The fracture surface investigation showed that several strengthening mechanisms, including particles pull-out, crack pinning, plastic void growth and deformation were the main factors for the increments of the tensile strength of the Al2O3/epoxy composites. Comparing with pure epoxy polymer, the creep strain values at 70 °C for 1800 s and recovery strain after 3600 s of 40vol.%Al2O3/epoxy composites was lower as 0.23% and 70%, respectively. It was due to effective prohibition of the slippage and disentanglement of epoxy polymer molecules by the rigid Al2O3.

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The Effect of Alkali Treatment on Physical, Mechanical and Thermal Properties of Kenaf Fiber and Polymer Epoxy Composites

Polymers ◽

10.3390/polym13122005 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2005

Author(s):

Nur Farhani Ismail ◽

Nabilah Afiqah Mohd Radzuan ◽

Abu Bakar Sulong ◽

Norhamidi Muhamad ◽

Che Hassan Che Haron

Keyword(s):

Tensile Strength ◽

Composite Materials ◽

Alkali Treatment ◽

Epoxy Composites ◽

Effect Of Temperature ◽

Mechanical And Thermal Properties ◽

Compression Moulding ◽

Kenaf Fiber ◽

Pull Out ◽

Kenaf Fibers

The use of kenaf fiber as a reinforcement material for polymer composites is gaining popularity, especially in the production of automotive components. The main objective of this current work is to relate the effect of alkali treatment on the single fiber itself and the composite material simultaneously. The effect of temperature condition during mechanical testing is also investigated. Composite materials with discontinuous natural kenaf fibers and epoxy resin were fabricated using a compression moulding process. The epoxy composites were reinforced with 50 wt% untreated and treated kenaf fibers. The kenaf fiber was treated with NaOH solution (6% by weight) for 24 h at room temperature. Kenaf fiber treated with NaOH treatment had a clean surface and no impurities. For the first time we can see that alkali treatment had a damaging effect on the mechanical properties of kenaf fibers itself and the treated kenaf/epoxy composites. The composite reinforced with untreated kenaf fiber and treated kenaf fiber showed increased tensile strength (72.85% and 12.97%, respectively) compared to the neat epoxy. Reinforcement of the composite with treated kenaf fiber decreased the tensile strength due to the fiber pull out and the formation of voids which weakens the adhesion between the fibers and matrix. The temperature conditions also play an important role in composites with a significant impact on the deterioration of composite materials. Treated kenaf fiber has thermal stability and is not sensitive to temperature and as a result reinforcement with treated kenaf gives a lower loss value of 76%.

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