1. Introduction
Due to the plastic thrash, the land, water, and air are polluted [
1]. If the plastics are dumped in the landscapes, they will block the percolation of rainwater into the land which leads to a decrease in the groundwater levels. If the plastics are thrown into water bodies, it leads to leaching, and the water gets polluted. We cannot burn the plastics, as it would release harmful gases into the atmosphere. To avoid the degradation of the earth, the used plastics have to be reused in some way. In the growing world, the need for alternate materials is increasing. At the same time, lots of landscapes are occupied by Prosopis juliflora plants, which makes it difficult to cultivate crops and also it absorbs the water and nutrients from the land and makes it uncultivable [
2,
3]. A lot of research works are undergoing to use these plants effectively for various applications. Kailappan et al. produced the activated carbon from Prosopis juliflora using a chemical method and proved it can be used in oil, food, and pharma industries [
4]. As the plastics are used in this composite, it can be used in automobile, marine applications where lightweight and less corrosive materials are required. Plastics have moisture repelling property and the Prosopis juliflora thorn powder provides hardness to the composites and also it fills the minute pores produced during the production of composites.
When Saravanakumar and his colleagues analysed the parameters of the fibres, they found that they had an average microfibril angle of 10.64 and utmost elongation strength of 558 MPa. It was found that the aspect ratio of the PJ fibres had a significant impact on the mechanical qualities of the finished product. A fibre aspect ratio of 136 and fibre loading of 23.53 wt. percent were found to yield the best mechanical properties. [
5]. The tensile and thermal properties of treated PJ fibres were shown to be superior to those of untreated fibres in a study by Madhu et al. [
6].
Structural applications may benefit from the properties of PJ fiber- and glass-fiber reinforced polymer composites, according to Manoj Kumar et al. [
7]. Due to the presence of lignin, researchers led by Luis Valencia found functional nanomaterials with a mean radius of 10 nm and a length of 150 nm in the PJ [
8]. Filler-reinforced epoxy composites can improve mechanical properties by as much as 45 percent, according to research by Santhosh et al., who studied the morphology and properties of PJ and RH—reinforced composites [
9]. PJ ash powder can be used as a substitute for cement up to 20%, according to Parthiban Kathirvel et al., and they were able to attain the same strength for their newly designed concrete [
10]. An onion-like porous carbon made from the PJ has been advocated as an efficient electrode material by Sathyanarayanan Shanmugapriya and his colleagues [
11].
The novel composites’ mechanical, tribological, and water absorption properties must be thoroughly investigated. It was discovered by Sakthi Balan et al. that adding 30 wt percent of waste plastic particle to jute fibre and waste plastic-filled composites resulted in high resistance to water absorption [
12]. Water absorption and tribological properties were increased by the inclusion of filler and fibres to the composite, which was made of plastic waste, fiber glass, and silica sand fillers. It has been reported that the thermal and mechanical characteristics of epoxy composites manufactured with 20% fibres and NaOH treatment have been improved [
13] by Arthanarieswaran and colleagues. Using dates palm seeds and glass fibre reinforced polymer composite, Heba I. Elkhouly et al. demonstrated an increase in the composite’s wear resistance and toughness. Tapas by Priyadarshi Tapas Ranjan Swain et al. made a composite out of jute fibres and studied how it wore. The wear resistance has been modified by the chemical treatment [
14]. They observed that the abrading distance was the most important element in determining the wear of waste silk fiber-reinforced epoxy composites [
15], followed by the loading of fibers.
Taguchi is an effective strategy for designing experiments. Materials scientists use it to their advantage when examining the effects of various process variables. Polymer-based composites are being made using the Taguchi method. Boron nitride reinforcement of Nylon composite was studied by Shiva Kumar and Chennakesava Reddy using the Taguchi approach and it was found that the composite’s wear resistance was improved by the addition of boron nitride [
16]. It was proposed by Wahid Ferdous et al. that the bond length and thickness for higher strength be studied using Taguchi design in polymer-based composites [
17]. Polymer composites with various reinforcements such kevlar, carbon, and glass fibers were subjected to the Taguchi technique by Karthik et al. in order to optimize the wear parameters [
18]. They found that the hybrid composites had improved wear behaviors. As a result of the Taguchi approach and ANOVA, Siva Prasad and Chaitanya were able to optimize the drilling parameters for the GFRP composites [
19].
Natural fibers have gained popularity and are beginning to supplant synthetic fibers, owing to their contribution to sustainable practices. As a result of environmental, social, and economic development, numerous industries have altered their manufacturing processes, materials, and procedures in order to ensure a sustainable future. While natural fibers have significant disadvantages, they can be overcome with appropriate chemical treatments and fiber processing. Numerous goods composed of natural fibers are developed and used in sports, electronics, and musical instrument manufacturing [
20]. Natural fibers exhibit comparable wear resistance to synthetic fibers. The wear resistance of natural fibers can be increased by reinforcing them with synthetic fibers [
21]. Recent research has concentrated on green fillers such as date seed powders, coconut and cashew nut shell powders, and rice and maize husks. Natural fibers and fillers are used in composites because they are inexpensive, widely available, biodegradable, recyclable, and lightweight [
22]. Researchers are becoming more interested in starch-based bioplastics due to their environmentally beneficial characteristics. Starches have been isolated from a variety of plants, including PJ plants, and bio composites have been constructed and tested for mechanical properties and biodegradability. The results indicated that composites might be used as a substitute material in the packaging industry [
1].
Plastic trash and PJ thorn granules are both included into the polymer matrix in this study. The motive of this work is to investigate the influence of chemical treatment, the amount of waste plastics, and PJ thorn powders on the composite’s hardness and moisture absorption and wear capabilities using the Taguchi technique.
4. Conclusions
PJ fibers are mixed with a variety of natural and synthetic fibers to create enhanced-property hybrid composites. Natural fibers’ high strength-to-weight ratio, longevity, and inexpensive cost make them an excellent choice for polymer composites. Natural fiber composites are widely used in defense, automotive, and marine applications. A composite is made and tested using glass fiber and PJ in powder form. The results indicate that adding 6% PJ powder to glass fiber composites leads in increased impact and compressive strengths, as well as increased hardness [
34].
In this study, the composite was created by combining waste plastic particles with Prosopis juliflora thorn powder according to Taguchi’s full factorial design and laying it out by spraying. The trials are carried out in accordance with ASTM standards, and the results are entered into a software programme for further optimization. According to the optimal values, the additions of thorn powder improves the hardness and wear resistance property, and the inclusion of waste plastics improves the resistance to moisture absorption and the tensile properties of the material. A material with a high hardness will have a higher resistance to wear due to friction and abrasion. The use of fillers increases the composite’s hardness, which is reflected in the composite’s wear rate [
35].
It is necessary to have a 30 weight percent composition of plastics, a 15 weight percent addition of thorn powder, and it must be silane treated in order to get maximum hardness. In order to get the lowest possible water intake while maintaining the highest possible tensile property, 30 weight percent waste plastic particles and 5 weight percent thorn powders must be incorporated. Due to the natural nature of the filler powder, its inclusion must be kept to a minimum to ensure optimal resistance to moisture absorption. Even if chemically treated, they will lose their hydrophobic properties in extreme circumstances and for extended periods of time, allowing water to permeate through the composites. Overall, chemical treatment had little effect on the hardness, tensile strength, or moisture intake characteristics of the material. Finally, in order to get the lowest possible abrasion wear, the maximum amount of polymers and thorn powder should be used. The validation tests are carried out for hardness in accordance with the projected levels, and it is discovered that the error value falls below the acceptability criteria.