Abstract
Bamboo fibre and bamboo yarn as reinforcing material in polymer composites has received global interest in the last two to three decades regarding its development and application using modern technology and equipment to produce objects with fewer adverse effects on the environment. Bamboo yarn-reinforced polymer composite products are derived from bamboo fibres which are readily globally available; they are biodegradable and eco-friendly with relatively low production cost and easy to fabricate compared to metals and synthetics. Bamboo yarns are renewable and provide an advantage to the environment since they reduce greenhouse gas emissions during their life cycle. The thermal, mechanical and surface morphologies of bamboo fibres/yarn are mostly modified for the manufacture of internal and external parts in automobile vehicles, aerospace, electronic gadgets, building and construction components due to its capacity for sustainable innovations through advanced technology.
This research presented a multidimensional study on the application of bamboo fibre and bamboo yarn as a polymer reinforced composite material by investigating optimal fibre extraction, treatment and yarn process methodologies by critically addressing techniques of culm harvesting and post-harvest treatment. Modern techniques and usage of eco-friendly chemicals in the extraction and treatment of the cellulose fibre, yarn production and yarn usage as a reinforcement in a polymer matrix to fabricate laminate plates were also addressed. Three selected bamboo species from Ghana (Bambusa vulgaris, Bambusa vulgaris vitata and Dendrocalamus strictus) with the first two being employed for the fibre extraction which was processed into yarn using sodium hydroxide and other acetic acid treatments in concentrations of 10%, 20%, and 30%. The treated bamboo fibres were further processed into yarn employing an eco-friendly alkaline solution. The processed bamboo yarn was innovatively handwoven into fabric using the Ghanaian traditional
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Kente weaving technique to enhance its mechanical stability with varying woven orientations of 45o, 90o or 180o. The innovative handwoven bamboo yarn fabric was employed as reinforcement in the polymer matrix composite for the manufacture of plates for structural works. Vacuum-assisted resin transfer moulding was employed for the fabrication of two varying woven orientations, 45o and 90/180o. The fabricated samples were characterised to evaluate the influence of chemical treatment and the woven orientations on the mechanical and thermal properties of the woven bamboo yarn reinforced polymer composites. Various characterisation tests were conducted on the (raw bamboo fibre and yarn) and on the produced laminate plate samples which include chemical, morphological, mechanical and thermal analyses. These analyses were performed using Raman microscopy and Fourier transform infrared spectroscopy, Nuclear magnetic resonance spectral analysis (solid-state microscopy), X-ray diffraction, Scanning electron microscopy and Brunauer-emmet-teller (BET). Further tests included tensile, bending/flexural, ballistic, impact, thermal analysis, elemental and chemical analyses. The test results showed there was a significant improvement in the chemical, mechanical and thermal properties on the BF and BY treated with NaOH and other acetic acid treatments, and the 30% NaOH treated fibre showing superior improvement compared to the 20% and 10%. Also, the 45o innovative hand woven orientation shows significant superior mechanical properties in tensile, compression, flexural and impact strength compared to that of 90o or 180o woven orientation. Significant interfacial bonding improvement existed between epoxy resin (matrix) and the woven bamboo yarn (reinforcement) but showed cracks/fractured surfaces in its interlaminar bonding. To quantify the test samples (laminate plate) parameters and sensitivity, statistical and finite element analysis on tensile, flexural/bending and compressive tests showed that optimal tab design configuration was necessary for minimising stress concentration. To minimize stress
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concentration effectively, a significantly lower tab stiffness and tab taper angle values were required while increasing the adhesive thickness. In summary, this work contributed to the scientific body of research in polymer composite by addressing a critical area of bamboo fibre and bamboo yarn as reinforcing material in polymer composites where characterisation and evaluation were conducted from harvesting, post-harvesting, fibre extraction, chemical treatment, yarn and fabric processing, weaving and fabrication of composite laminate. This results are highly commendable and can be commercialise in Ghana and other parts of the African continent to enhance human capacity building.
Keywords: Bamboo; Bamboo Yarn; Characterisation; Chemical Treatment; Polymer Composite.