Description:Field of the Invention
The present invention relates to,the process of creating natural composites using cashew nut shell liquid and coir fiber. A material with good mechanical characteristics was created by selecting various fiber and matrix mixes.

Objectives of the invention
The objective of this invention is to contribute to environmental conservation, reduce pollution, and promote sustainable development. Natural composites, derived from renewable resources, offer a promising alternative to synthetic materials in various applications.
Background of the invention
Derived from the outer husk of the coconut, coir is a natural lignocellulosic fiber. It originates from the fruit of the Cocos nucifera, a tropical plant belonging to the Arecaceae (Palmae) family. This fiber is coarse, rigid, and reddish-brown, consisting of fine threads that measure between 0.01 to 0.04 inches in length and 10 to 25 micrometers in diameter. The fiber cells are tiny, hollow, and have thick walls composed of cellulose (Fouladi, et al., 2011). When young, these fibers are lightweight, but as they mature, they become harder and turn yellow due to the development of a lignin layer on their walls. Mature brown coir fibers contain more lignin and less cellulose compared to flax and cotton fibers, making them stronger yet less pliable. They consist of tiny strands that are shorter than 0.05 inches and have diameters ranging from 10 to 20 micrometers. Coir fibers are notably water-resistant and stand as the only natural fiber resistant to damage from saltwater. Brown fibers are obtained by harvesting fully ripe coconuts when the surrounding nutritious layer is prepared for copra and dried coconut production. The fibrous husk is then manually removed from the tough shell by pressing the fruit onto a spike and splitting it open.
CNSL is a thick, reddish-brown liquid extracted from the shells of cashew fruits (Anacardium occidentale), which thrive in various tropical and subtropical climates. Originating from Brazil and coastal regions of Asia and Africa, the cashew tree is now cultivated extensively in countries like India, Vietnam, Mozambique, Madagascar, Tanzania, the Philippines, and other tropical areas.Methods such as roasting, immersion in hot oil, steam treatment at 270°C, rapid heating at 300°C, cold methods, and solvent extraction are employed to extract CNSL from the shell(Hughes, 1930)(Solomon, 1945). The extracted CNSL contains a range of valuable phenolic compounds combined with long-chain saturated/unsaturated hydrocarbons in a meta-substituted form, making them suitable for various polymerization processes through addition and condensation reactions. Additionally, the aromatic ring combined with a lengthy hydrocarbon chain provides an optimal balance of rigidity and flexibility in coatings. Due to their structural resemblance, CNSL and its derivatives can serve as safer alternatives to hazardous phenolic compounds used in resin production, such as phenols in phenolic resins and bisphenol-A in epoxy resins, offering improved properties.

Summary of the Invention
In the present innovative invention, tensile, flexural, and hardness tests were used to thoroughly evaluate the mechanical characteristics of composite materials made of coir fibers and a CNSL-polymer matrix.
The ultimate aim is to increase the strength and other mechanical characteristics of the composite material made up of coir fiber and a CNSL-polymer matrix.
The key features of the fabricated material observed in this invention depended upon the weight percentage of coir fiber and its orientation and also the amount of resin penetrated into the fiber which eventually increases the mechanical characteristics of the material.
Detailed description of the invention
Natural fibers are categorized as either derived from plants or animals. Plant-based fibers are primarily composed of polysaccharides, while animal-based fibers consist mainly of proteins. To use these fibers effectively as reinforcements, they need to be separated from any binding substances present in the raw materials, such as hemicelluloses, lignin, waxes, and proteins. Nature abundantly synthesizes a wide range of fibers with varying thermal and mechanical characteristics, making them suitable for the creation of high-performance bio-composites. Unlike their synthetic counterparts, vegetable fibers exhibit a wider range of mechanical properties influenced by factors like plant maturity, geographical location, climate conditions during growth, harvesting techniques, and refining processes. Furthermore, the availability of significant amounts of a certain kind of bast fiber is geographically dependent: Flax and hemp are commonly found in cooler climates, while jute and kenaf are more prevalent in tropical areas.
When used as reinforcement in composites, natural fibers are typically combined with a matrix material like thermoset or thermoplastic polymers to enhance mechanical properties. These resulting composites, known as natural fiber-reinforced materials (NFRCs), find applications in consumer goods, packaging, automotive components, and construction materials. As natural fibers can vary in strength, moisture absorption, and dimensional stability, one of the difficulties in employing them as reinforcement is guaranteeing constant quality and qualities. Ongoing research and development initiatives, however, are concentrated on resolving these issues and enhancing NFRC performance for a variety of applications. Current studies are concentrating on the mechanical properties of the adaptable coir natural fiber.
The main constituents of CNSL differ based on the tree's geographical location, mainly comprising anacardic acid, cardanol, and cardol, with anacardic acid making up 70 to 80% of the content. When heated, anacardic acid undergoes decarboxylation to produce anacardol, which can then be hydrogenated to form cardanol. THe cardanol's aliphatic side chains usually contain one, two, or three double bonds. It consists of four components with varying degrees of side-chain unsaturation. Due to its phenolic nature, cardanol can undergo condensation polymerization with formaldehyde to produce cardanol formaldehyde (CF) resins. CF resins exhibit distinct characteristics, including resistance to high temperatures, retention of stiffness at elevated temperatures, resilience to chemicals and detergents, high surface durability, and cost-effectiveness.
The cardanol produced from bio-organic CNSL and formaldehyde was used to make cardanol resin when sodium hydroxide, a basic catalyst, was present. As a result, the resin was made utilizing a precise ratio of CNSL, HCHO, and NaOH reactants to 1: 2: 0.2, or 200:50: 5.5 by weight (grams). 200 grams of CNSL were placed in a bottle, and 5.5 grams of NaOH were dissolved more slowly over 30 minutes with the use of a magnetic stirrer as the primary catalyst. The extra mixture was removed and let to rest at room temperature for a day in a separating funnel. Over time, a poly-condensation process occurs, leading to the formation of a settling mud-colored resin and an unreacted dark brown liquid layer on top. The reactive resin was then isolated using a magnetic stirrer and transferred to a double-neck round-bottom flask. This flask was placed in an oil bath and heated to temperatures ranging from 100 to 150 degrees celsius for three hours to enhance viscosity. Subsequently, the resin was collected and allowed to cool to room temperature. Different amounts of CNSL and hardener were used in a similar manner.
The coir fibers are frequently subjected to alkali treatment, also referred to as mercerization, to improve their characteristics and increase their compatibility with polymer matrices in composite materials. Impurities such as lignin, pectin, waxes, and other non-cellulosic materials can be found in coir fibers. Cleaner and more consistent fibers are the outcome of the alkali treatment's assistance in removing these contaminants. By hydrolyzing lignin and hemicellulose, alkali treatment modifies the surface chemistry of coir fibers, introducing hydroxyl groups and raising surface roughness. In composites, this alteration improves the adherence of fibers to polymer matrix. The coir fibers' cellulose microfibrils expand as a result of the alkali treatment, increasing the fiber's diameter and roughening its surface. The enhanced roughness of the surface boosts both the overall strength and stiffness of the composite, facilitating better mechanical bonding between the fibers and the polymer matrix. Alkali treatment of coir fibers results in the development of hydroxyl groups on their surface, which encourages hydrogen bonding with polymer matrices like thermoset resins (like epoxy) or thermoplastic polymers (like polypropylene). This enhanced adhesion allows for improved load transfer between the fibers and the matrix, resulting in a composite with enhanced mechanical properties. By partly eliminating hemicellulose and lignin, an alkali treatment can lessen the hydrophilicity of coir fibers, hence decreasing their propensity to absorb moisture. This characteristic is especially helpful in situations where the absorption of moisture may cause dimensional instability and mechanical property loss. Coir fibers of 0.15 to 0.30 diameter,100 to 200 mm long were soaked in aqueous solution of NaOH (30 w%) for an hour. Approximately 30 grams of coir was soaked in alkali solution. After soaking for an hour, the fiber was taken out of the solution and washed with distilled water to eliminate any remaining NaOH on its surface. Subsequently, the processed alkali-treated fiber was air-dried for 24 hours.
The specimens for the tensile test were sized using emery paper after being cut from the fabricated composite. Testing was conducted on the three samples using a Universal Testing Machine following ASTM D 638 guidelines. There are around 54, 13, and 13 examples of each length, breadth, and thickness, respectively. The graph below displays the relationship between representative load, yield stress, yield load, and elongation, and is directly loaded from the machine. It is important to observe that all of the curves in this image represent the specimen's first grip adjustment up to 146N or the linear elastic stage. The graph in this region will demonstrate a linear connection between the load and displacement/strain. The elastic modulus, also called Young's modulus, is a linear region whose slope indicates how stiff the material is; it is possible to determine the material's stiffness from this region. The elastic area is followed by the material's yield point. Following this, the material undergoes plastic deformation, meaning it doesn't revert to its initial shape once the load is removed. A brief decrease near the conclusion of the elastic area shows that there was little plastic expansion when the rupture happened. This indicates that the composite material is ductile.The peak of the curve indicates the material's ultimate or tensile strength, representing the maximum stress or strain the material can withstand before breaking. Here the ultimate strength recorded for the three specimens is mentioned in the table with the other tensile properties which are calculated from the load vs elongation graph.
Lastly, it's worth noting that compared to composites with 85% coir fiber volume fraction, the material with 80% coir fiber has a higher Ultimate Tensile Strength (UTS) of 1.35 MPa, whereas the 85% coir fiber composite has a UTS of 0.96 MPa. A higher UTS indicates that material with 80% coir fiber can withstand higher loads before breaking.Material with 85% coir fiber has a slightly higher yield stress (0.91 MPa) compared to Material with 80% coir fiber (0.86 MPa). A higher yield stress indicates that Material with 85% coir fiber can withstand higher loads before undergoing plastic deformation.Material with 80% coir fiber has a higher elongation (7.24%) compared to Material with 85% coir fiber (4.2%). Higher elongation indicates better ductility, meaning Material with 80% coir fiber can undergo more deformation before breaking.Taking these factors into account, Material with 80% fiber seems to have superior overall mechanical qualities, particularly if the application calls for high tensile strength and ductility. The "better" material, therefore, partly relies on the particular specifications and circumstances of the application. Material with 85% can be preferred if yield stress or a balance of characteristics is more important for the application
The samples, measuring 8 mm in diameter and 50 mm in length, were readied for the Shore-D Hardness test following the ASTM D 2240-2015(2021) standards applicable to composites. Two significant elements that influence the composite's qualities are the volume percentage and fiber configuration. The configuration allowed for this test is restricted to discontinuous and randomly oriented fibers. Through the application of an indentation load normal to both the fiber's diameter and length, the hardness characteristics of the composites are investigated. In general, fibers that raise a composite's modulus also raise the composite's hardness. This is so because relative fiber volume and modulus determine hardness.
Brief Description of Drawing
Thefigures which are illustrate exemplary embodiments of the invention.
Figure 1 SEM images of untreated and treated coir.
Figure 2 The fabrication process.
Figure 3 Mechanical property graphs of the produced material.

Detailed description of the drawing
As described above the present invention relates to
The surface morphology of both untreated and treated coir fibers is captured using a scanning electron microscope, as Figure 1 illustrates.

Figure 2 depicts images of the steps involved in creating a material using CNSL resin and coir fiber.

The graphs between the mechanical parameters that were noted for the manufactured material are displayed in Figure 3. , Claims:The scope of the invention is defined by the following claims:

Claim:
1. The fabrication process of a natural composite material, wherein the the modified composite material comppsing cashew nut shell liquid and coir fiber comprising the following steps,
a) The resin was made utilizing a precise ratio of CNSL, HCHO, and NaOH reactants to 1: 2 by weight (grams).
b) The coir fibers are frequently subjected to alkali treatment, also referred to as mercerization, to improve their characteristics and increase their compatibility with polymer matrices in composite materials.
c) The hand lay-up method was employed to fabricate the composite material. The designated quantity of coir fiber (50% by weight) was obtained, along with a mixture of CNSL, HMTA (hardener), and epoxy resin (50% by weight).
2. As mentioned in claim 1, the reactive resin was isolated using a magnetic stirrer and transferred to a double-neck round-bottom flask. The flask was placed in an oil bath and heated to temperatures ranging from 100 to 150 degrees Celsius for three hours to enhance viscosity. Subsequently, the resin was collected and allowed to cool to room temperature.
3. According to claim 1, the composite with 80% coir fiber exhibits an ultimate tensile strength (UTS) of 1.35 MPa, a yield stress of 0.86 MPa, and an elongation of 7.24%. The composite with 85% coir fiber has a UTS of 0.96 MPa, a yield stress of 0.91 MPa, and an elongation of 4.2%.
4. As per claim 1, the composite's Shore-D Hardness is influenced by fiber loading and post-curing time, with both compositions exhibiting varying hardness levels.