The hunt for reduced-energy consumption technologies and reduced environmental impact has needed the advancement of natural fiber-reinforced blends (NFRBs) in different diligence. Natural fibers show multifaceted advantages compared to synthetic fibers, like biodegradability, featherlight, low cost, low viscosity, sound sequestration, and enhanced life-cycle performance characteristics [1–3]. The choice of accouterments and design exerts an essential function in engineering design. The accouterments must have excellent physical, thermal, and mechanical properties to produce bettered papers and fulfill client conditions. The growth of ultramodern processes, growth in population, industrialization, and limited accommodation has touched off the emergence of construction and automotive diligence encyclopedically [4]. As a result of the attainability of ultramodern construction accouterments, there is a demand for indispensable structure accouterments. Exercising natural coffers to make biodegradable compound accouterments is one similar stride toward conserving the terrain. Blends fabricated from natural fibers as mounts are a volition in this line [5].
The matrix material is a demand in the product of NFRBs to hold natural fibers and paddings to form a compound structure [6]. Epoxy resin has been considerably applied as a matrix base in NFRBs owing to its remarkable bruise properties, good electrical separating quality and resistance to humidity and chemical attacks, better mechanical strength, and notable adaptability [7–9]. Epoxy resin cures without curing agent or heating at ambient temperature devoid of pressure [10]. Prileschajew [8] was the first to report epoxy resin in 1909. Still, the original marketable manufacture of epoxy resin started in the late 1940s. Epoxy resin bonds were commercially available in the early 1950s, and progressive inventions are achieving in multitudinous operations. In 1953, the Shell Chemical Corporation introduced field assessments to test for epoxy resin systems as surfacing accouterment on roadways [11]. Also, in 1953, the leading operation of epoxy resin seal coating as test doctoring in artificial shops was arrived at. In 1957, epoxy resin polymer concrete was employed as the original wearing route to amend mars and slivers on the shells of ground balconies in California [7]. Lately, epoxy resins have worked as a resin with natural fiber mounts in different construction operations and machine fields, like thin-subcaste non-skid surfacing for roads and islands, aerospace diligence, and casing [8].
During the harvesting season of crops, expansive quantities of bio-fiber wastes are generated yearly in agro-processing diligence, in addition to beast husbandry. These wastes come in solids, liquids, or slurries form, and their composition is determining by their colorful sources [12]. In the most industrialize economies, substantial quantities of these wastes are used as raw accouterments by other manufacturers to lessen their adverse effect on humans and the terrain [13, 14]. Again, in an underdeveloped and rising economy, the use of these wastes for bang-for-the-buck products is stingy. Although agrarian enterprises are on the rise in utmost arising husbandry to attain the target tone-reliance in food manufacture, multitudinous waste-accruing from this rigorous husbandry hasn't gained enough mindfulness, specifically in Africa. As a result, the peril owing to waste jilting and poor sanitation is necessary. Approximations of wastes arising from agrarian conditioning are unlimited. Still, they're considering subscribing to a remarkable quantum of the total waste matter in several metropolises worldwide [15]. Still, studies on the application of solid agro wastes are sluggishly gaining recognition from the exploration community with little or no zero attention from enterprises in developing countries. The application of these wastes as paddings in polymer blends [16], nanofillers in buttressing plastics and rubber [17, 18], lignin-grounded cellulose nanomaterials [19, 20] biodegradable polymer flicks [21], and multitudinous other functional accouterments described. The outstanding mechanical properties and biodegradability of agro-waste have positioned them as indispensable buttressing accouterments in polymer blends [22] and towel engineering [23].
Bambara nut shells are great bio-fiber agro-waste in Africa that are by-products deduced from the processing of Bambara seeds into flour for mortal consumption. The obtained fiber gotten after breaking the seeds in a waste shop to separate the shells through winnowing to bring out detached testa and transubstantiating the cotyledons into fine flour by mulling constantly, followed by sieving. In Nigeria and some African countries, large quantities of this nut are cultivated yearly (Table 1). The shells serve as refection for some beasts [24], therefore minimizing their operation, while a substantial volume is dumped in a waste caddy, giving rise to environmental hazards [25]. Using agro-waste as underpinning for thermoplastics and thermosets is a valorization pathway that will break the binary challenge of environmental and profitable sustainability.
Table 1
Approximated production of bambara nut in some African countries [26]
S/N | Country | Approximated production (metric tons) |
1. | Nigeria | 100000 |
2. | Botswana | 6000 |
3. | Togo | 4400 |
4. | Burkina Faso | 44712 |
5. | Cameroon | 24000 |
6. | DR. Congo | 10000 |
7. | Mali | 23165 |
8. | Zambia | 18750 |
9. | Zimbabwe | 750 |
10. | Ghana | 20000 |
11. | Niger | 30000 |
12. | Cote d’ivoire | 7000 |
13. | Chad | 20000 |
Multitudinous experiments are studying toughening/strengthening agents to ameliorate the properties of epoxy resin in structural and automotive operations [27–29]. Meanwhile, incorporating nano-silica, thermoplastic factors, inorganics, carbon fibers, graphene, clay, and carbon nanotubes enhances the durability of epoxy resin [30]. The usual physical and mechanical properties of epoxy resin shown in Table 2 [31–34]. The epoxy resin matrix bears resin and hardener that are generally in a rate of 10:1. The epoxy resin has an expansive range of operations, like those used for coatings, aerospace diligence, blends, the bio-medical sector, and electronic widgets. Applsci-13-05126
Table 2
Physical and mechanical properties of epoxy resin [31–34]
Appearance | Colorless to pale yellow liquid |
Flexural strength (MPa) | 40–67 |
Specific gravity (kg/m3) | 1120–1150 |
Viscosity at 25oC (kg/ms) | 0.25–0.75 |
Heat distortion temperature (oC) | 50 |
Solid content (%) | 84 |
Modulus of elasticity (MPa) | 3100–3800 |
Tensile strength (MPa) | 90–120 |
Max percentage elongation (%) | 4 |
Impact strength (kg/m2) | 9 |
Glass transition temperatures | 150-220oC |
As a result of their eco-friendly advantages, natural fibers play a vital part in colorful engineering operations, including automotive, structure, aerospace, and packaging. Compared to glass fiber and carbon fiber blends, which have limited exploration conducted on their reuse and recovery. Alamri and Low [35] reported colorful fiber ladings of different chance weights in advance to produce reinforced epoxy resin-reclaimed cellulose fiber blends. The results showed that flexural strength, flexural modulus, fracture durability, and impact strength increased when the fiber content increased. With 46 wt% fiber content, mechanical properties are at their optimum. The water immersion effect on the mechanical and physical properties of RCF/epoxy resin mixes is delve. The optimum water immersion and prolixity measure surged as the fiber content increased. As humidity immersion increased, the flexural strength, flexural modulus, and fracture durability reduced. But, with water immersion, the impact strength is observed to increase [36]. Paper wastes manufactured from recycled cardboard boxes, soya oil painting-grounded resin, and cellulose fibers are successfully applied to fabricate the compound structures. Epoxy resin mixtures produced from recycled ingredients generally have binary composites, and the first is to minimize destruction, and the second is to get high-strength compounds from these wastes.
This exploration ideal is to probe the effect of Bambara nut shell fiber lading on the physical, mechanical, thermal and morphological characteristics of epoxy resin blends filled with bio-fiber agro-waste deduced from Bambara nut shell fiber.