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The microstructure (i.e., fibre volume fraction, void content, and fibre misalignment) of unidirectional carbon fibre-reinforced polymer (CFRP) composites was optimised by controlling several parameters during manufacture, namely: (i) compressive pressure (0.25~1.25 MPa, in steps of 0.25 MPa), (ii) vacuum pressure (−0.15, −0.20, −0.30, −0.45, and −0.65 MPa), and (iii) holding temperature (100~140 oC, in steps of 10 oC), applied during autoclave curing with the holding time being 30 minutes for all specimens. Optical micrographs captured from cross-sectional, through-the thickness areas, and in-plane areas of the resulting composites were evaluated and analysed in order to describe their microstructural characteristics.

The flexural behaviour of 6-ply unidirectional hybrid fibre-reinforced polymer (FRP) matrix composites containing a mixture of E-glass and S2-glass fibres was investigated. A high performance epoxy system comprising of Kinetix® R240 epoxy resin (combined with Kinetix® H160 epoxy hardener) was utilised for the composite matrix. Flexural testing was conducted in accordance with Procedure A of the ASTM D790-03 test standard on a universal testing machine equipped with a three-point bend test rig. In addition to varying the stacking configurations of the composite prepregs, the influence of span-to-depth ratio on the flexural properties and failure mechanisms was also studied. The failure mechanisms of the resulting fractured specimens were characterised using optical microscopy and compared with those noted by the authors in previous work.

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The current work deals with the tensile and flexural properties of bamboo fiber/epoxy composites. Tensile and flexural property evaluations were carried out in accordance with the ASTM D638 and ASTM D790 standards, respectively. Bamboo fiber was obtained from local bamboo by means of degumming process. The matrix being used is Eposchon general purpose Bisphenol A-epichlorohydrin epoxy resin mixed with Eposchon general purpose Polyaminoamide epoxy hardener supplied by P.T. Justus Kimiaraya. The specimens were cut from five bamboo fiber/epoxy composite panels. Five different fiber volume fractions, Vf, i.e. 0, 10, 20, 30 and 40 vol%, have been considered. All mechanical and physical characterization were carried out at the Mechanical Engineering laboratory, Universitas Muhammaiyah Yogyakarta. Photo macrographs of selected samples were analyzed to describe their failure modes. Physical property evaluation revealed that a slight fiber content deviation from their expected results was observed. Whilst tensile strength, modulus and strain to failure, as well as flexural strength and modulus were found to increase with the increase of fiber content up to 29.8%, maximum flexural strain to failure was being at Vf = 21.1%. Tensile specimens were mostly failed by debonding followed by fiber breakage, while flexural specimens were mostly failed by debonding followed by fiber breakage and fiber pull-out at tension sides.

Antimicrobial and anti-diabetic of Curcuma mangga Val properties have attracted research interest. Curcuma mangga Val extract (CME) and poly (vinyl alcohol) (PVA) were blended and fabricated to the fibrous membranes by the electrospinning method. The effects of CME concentration on the fiber morphology and tensile properties of CME/PVA membranes are the goal of the current study. Scanning electron microscopy (SEM) of the membranes revealed bead-free fibers with straightly/continuously orientation formed in all CME/PVA membranes. The average fiber diameter increased from 186 nm to 297 nm, with the CME concentration from 0 to 3 wt.%, respectively. The addition of 1% CME resulted in a relatively high tensile strength of 24.96 ± 0.20 MPa, which is the highest among the CME/PVA membrane specimens. However, very high tensile modulus and low elongation showed in these results lead to reducing the functionality of the CME/PVA fibrous membrane due to the brittleness. The CME properties may contribute to those shortages.

Sisal, carbon, and poly-methyl methacrylate (PMMA) are the component materials that have been developed for the biomedical composite. However, characterization of the mechanical properties of the composites affected by some modified treatments is still opened for discussion. Sisal/poly-methyl methacrylate (PMMA) and sisal/carbon/PMMA composites with 30% fiber content and 6 mm fiber length were manufactured using a cold press molding at room temperature for about 60 min curing time. Tensile and bending properties of the composites were investigated by the influence of alkalization, the addition of maleic-anhydride-grafted polypropylene (MAPP) and hybridization of sisal and carbon fibers. The results indicated that the addition of MAPP (3, 5 and 10 wt. %) increases the tensile and flexural strengths of sisal/PMMA composites which are higher than the composites reinforced with alkali-treated and untreated sisal fibers. The addition of 5 % MAPP resulted in more effective improvement in mechanical properties compared to the effect of alkalization. However, a significant enhancement of tensile properties was shown by the hybridization effect of sisal and carbon with a ratio of 1:1 and 1:2 in sisal/carbon/PMMA composites. Scanning electron microscopy (SEM) of tensile fracture surfaces confirmed the presence of a functional relationship between the high mechanical strength of the composites with excellent adhesion between sisal fiber and PMMA by introducing 5% MAPP. Relatively homogeneous fiber dispersion in the matrix either sisal fibers or mixed sisal and carbon fibers within the PMMA matrix with sisal/carbon ratio of 1:2 have also contributed to the improvement of the mechanical strength. The use of alkali-treated sisal and HNO3-treated carbon fibers had promoted a remarkable increase in tensile strength of the sisal/carbon/PMMA hybrid composites.