OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 3 2024 matrix. The fibers in the matrix can be either woven or non-woven, with woven patterns typically consisting of continuous perpendicular yarns. Depending on its arrangement in the matrix, the fibers are classified as unidirectional or bidirectional. Depending on the type of fibrous reinforcing component used, green composites can also be divided into materials with continuous reinforcing fibers in unidirectional and bidirectional forms and materials with dispersed reinforcing fibers [6]. Natural fibers come in various types, including bast fibers, leaf fibers, seed fibers, fruit fibers, and stem fibers. Understanding the chemical composition and interfacial adhesive bonding of these fibers is important for optimizing the performance of natural fiber-reinforced composites. The key components of these fibers include cellulose, hemicellulose, lignin, pectin, waxes, and water-soluble substances. Despite its advantages, natural plant fibers have several disadvantages, such as high moisture absorption, which can lead to fiber swelling and dimensional changes in the final composite material. In addition, the irregular geometry of natural fibers poses challenges in modeling and predicting the behavior of green composites. These factors need to be carefully controlled to fully utilize the potential of natural fibers in green composites [7]. Matrices in Green Composites In green composites, the matrix plays a vital role as a homogeneous phase that determines the overall properties of the composite. It acts as the final component in the composite structure, anchoring the reinforcing fibers in place, forming the structure and uniformly distributing the load throughout the composite [8]. The matrix is important for the mechanical properties of the green composite, which significantly depend on the properties of the polymer matrix. There are two main types of matrices used in green composites: thermoplastics and thermosetting plastics. Thermosetting plastics usually include phenols and polyesters, while polyvinyl chloride, polypropylene and polyethylene are commonly used as thermoplastics. The use of these materials instead of traditional ones is due to the improvement of the specific properties of the composites [9]. In addition to providing structure, the matrix also prevents abrasion and the formation of new surface defects. The matrix maintains the arrangement of the fibers, allowing the composite to deform under load, transmitting and uniformly distributing the stress along the fibers. The choice of matrix materials can vary from petroleum-derived non-biodegradable polymers such as epoxy resins, polyethylene and polypropylene to biopolymers such as epoxy resins, polyhydroxybutyrate and PLA. These polymers determine the performance and environmental impact of green composites, among which polyethylene, polypropylene and polylactic acid are widely used [10]. Manufacturing of Green Composites The manufacturing green composites has evolved along with advances in materials science. Currently, various technologies are used, including hand lay-up, vacuum molding, injection molding, polymer transfer molding, pultrusion, and compression molding. Each method affects the mechanical properties of the composite by changing the integrity of the fiber bond and the surface morphology. Compression molding and hand lay-up are widely used for the production of thermosetting matrices, while injection molding and screw extrusion are widely used for thermoplastic matrices. The chosen manufacturing technology significantly affects the behavior of the material, ensuring that the mechanical properties are optimized without causing damage or cracks [11]. Botanical Description of Sida cordifolia Sida cordifolia, a member of the Malvaceae family and native to India, is an attractive plant due to its constant availability throughout the year. It is an annual or perennial woody subshrub that typically attains a height of 0.5–1.0 m. It features a softly hairy or greyish-green appearance and is characterized by its pubescent texture. The leaves of Sida cordifolia are simple, downy, and alternate, measuring 2.5–5 cm×1.8– 3 cm as shown in Figure 1. The stipules are arranged linearly on the petioles. The flowers are bisexual,
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