Comparative Study of Epoxy Composites Reinforced with Kenaf Fiber and Different Types of Microparticles

Abstract

Reinforcement of both fibrous and particulate materials can improve composite properties for various applications, such as biomedical applications. The alkali-treated kenaf fibers and (SiO2, bentonite, and CaCO3) microparticles 400 mesh in size reinforce the epoxy matrix for hybrid composites. The bending and impact properties of hybrid composites, as well as their water absorption, are compared. The hybrid composites were prepared in a compression mold using a hand lay-up technique at 100°C for 20 – 50 minutes consisting of 28 vol.% of short kenaf fibers ~5 mm in length, 2 vol.% of each type of microparticle, and 70 vol.% the epoxy resin. The flexural and impact properties of kenaf/silica/epoxy composite indicated the highest flexural strength (58.37±3.9 MPa), flexural modulus (4.68 ± 0.17 MPa), and impact strength (7.49 kJ/m2). The addition of the microparticles reduced water absorption in the composites. The water absorption of kenaf/silica/epoxy composite appeared to be stable for immersion time near 216 hours. Other microparticle-filled composites did not show this pattern. The incorporation of silica microparticles to the kenaf/epoxy composite potentially enhanced the mechanical properties of the composite, with the expectation of using it to be developed for biomedical composite material.

Changes in the properties of kenaf/silica/epoxy hybrid composites by variations in silica particle sizes and contents

“…Our prior investigation has reported an optimum silica content of 2 vol.% for impact strength and flexural properties of alkali-treated kenaf/silica/epoxy hybrid composite [9]. Additionally, adding silica microparticles to alkali-treated kenaf/epoxy could increase mechanical strength more effectively than calcium carbonate and bentonite microparticles [13]. Moreover, the untreated-woven kenaf and silica nanoparticles reinforced epoxy composite′s tensile strength increased with the silica nanoparticle concentrations (0, 5, 13, and 25 wt.%).…”

“…It is caused by partially dissolving the non-cellulosic substances in the alkali solution, increasing the fiber surface roughness, which improves the mechanical strength [8,11,12]. In addition, kenaf/silica/epoxy composite showed higher properties than other particulate reinforcement at a similar particle size and concentration [13].…”

The mechanical and physical properties of microcrystalline cellulose (MCC)/sisal/PMMA hybrid composites for dental applications

“…It used a specimen dimension of 127 mm×12.7 mm×3.2 mm, and the depth of the notch was 10.16 ± 0.05 mm with an angle of 45 ± 1°. The test was conducted according to the ASTM D6110 standard [22]. A hardness Vickers (Hardness Testing Machine Mitutoyo HM-200) was utilized for hardness testing on the specimen with a dimension of 30 mm×10 mm x 3.2 mm, in which the load was fixed at 50 g for 15 s [23].…”

“…A water absorption test was conducted following the ASTM D570 standard, with a specimen dimension of 76.2 mm×25.4 mm×3.2 mm [22]. Before immersing in distilled water at room temperature for 216 h, the weight of the specimens was measured.…”