Mechanical and Tribological Behaviour of Natural Fiber (Eulaliopsis Binata) Reinforced Polymer Composite

Abstract

Environmental awareness today motivates the researchers, worldwide on the studies of natural fiber reinforced polymer composite and cost effective option to synthetic fiber reinforced composites. The availability of natural fibers and ease of manufacturing have tempted researchers to try locally available inexpensive fibers and to study their feasibility of reinforcement purposes and to what extent they satisfy the required specifications of good reinforced polymer composite for different applications. With low cost and high specific mechanical properties, natural fiber represents a good renewable and biodegradable alternative to the most common synthetic reinforcement, i.e. glass fiber. Despite the interest and environmental appeal of natural fibers, there use is limited to non-bearing applications, due to their lower strength compared with synthetic fiber reinforced polymer composite. The stiffness and strength shortcomings of bio composites can be overcomed by structural configurations and better arrangement in a sense of placing the fibers in specific locations for highest strength performance. Accordingly, extensive studies on preparation and properties of polymer matrix composite (PMC) replacing the synthetic fiber with natural fiber like Jute, Sisal, Pineapple, Bamboo, Kenaf and Bagasse were carried out. These plant fibers have many advantages over glass fiber or carbon fiber like renewable, environmental friendly, low cost, lightweight and high specific mechanical performance. There are many potential natural resources, which India has in abundance. Most of it comes from agriculture or forest. Eulaliopsis Binata (EB) fiber (locally known as “sabai fiber”) is one of such fiber whose potential as a reinforcement material in the PMCs has not been studied to an extent that comparable to jute, banana, bamboo, sugarcane etc. This fiber plant belongs to “poacceae” family of plant kingdom, which is known for its good fiber quality. These plants are grown in the eastern part of India along with some Asian countries such as China, Nepal, Pakistan, Myanmar, Thailand, Philippines, and Malaysia etc. The eulaliopsis binata (EB) fiber plant is generally grown on waste lands and also contributes to the soil conservation of the inclined and waste lands. The fiber quality of this plant could be recognized by its existing applications of the fibers as rope, mats, carpets, sofa sets, wall hangings and other sophisticated, fashionable articles, which have proved its worth as a structural material with reasonably good mechanical properties. A fiber to be used as reinforcement material must possess cellulose, hemicellulose and lignin along with other constituents like carbon, which makes it lighter. This fiber structure consists of 52% cellulose, 27% hemicellulose and 17% lignin along with other constituents such as ash and moisture etc. The constituents of the fiber material conform the requirements to be used as a reinforcement material in polymer based composites for structural and other applications. In India, the EB plants are cultivated in various parts of India such as Odisha, Uttar Pradesh, Bihar, West Bengal, Punjab, Haryana and Himachal Pradesh. The availability of EB fiber in India is about 3, 50,000 tons out of which only 82,000 tons are used in paper industry. The EB fiber is provides 25% of total fiber raw material requirement of India for various applications. These plants once grown, provide yield for 10-15 years and the cost of cultivation per acre decreases with progressing years from 47.89 dollar from the 1st year to 5.44 dollar in the 12th year due to lower maintenance requirements. From the economic point of view, EB plantation is very economical with an average net return 323 dollars per annum from the degraded lands whose opportunity cost is almost zero. The cost of EB long fibers per kilogram varies between 5-8 Indian rupees. The EB plants are considered to be the “money plants” due to cheap and profitable cultivation throughout the year. Against this background, the present research work has been undertaken with an objective to explore the use of natural fiber Eulaliopsis Binata as a reinforcement material in epoxy base. The work presented in this dissertation involves investigation of three distinct problems of natural fiber composites: i. A study of favorable mechanical properties of Eulaliopsis Binata fiber in thermosetting matrix composite. ii. Investigation of weathering behavior of Eulaliopsis Binata fiber composites and its influence on the mechanical performance iii. An experimental investigation of tribological properties (abrasive and erosive) of Eulaliopsis Binata reinforced epoxy composite. To study the mechanical properties of the composite, different weight fractions of fiber have been taken. Usual hand-lay-up technique has been adopted for manufacturing the composite. To have a good compatibility between the fiber and matrix, chemical modification of fibers such as acetone,
alkali, and benzoyl-chloride and treatments has been carried out. It was found that benzoyl-chloride treated fiber composite exhibits favorable strength and stiffness in comparison to other treatments. Moisture absorption behavior of both treated and untreated fiber composite was also carried out. The moisture absorption kinetics of the composite has also been studied. The study confirms that the Fickian’s diffusion can be used to adequately describe the moisture absorption in the composite. The EB fiber epoxy composites exhibited better abrasive wear resistance properties as compared to neat epoxy. However, it is limited to twenty weight percent in comparison to thirty weight percent for strength and modulus under all tested conditions. The formation of fibrils and debonding between fiber and matrix material due to low load transfer is the main cause of reduction in fiber content for wear analysis. To study the tribo-potential of Eulaliopsis Binata fiber, solid particle erosion behavior by air jet erosion test rig have been carried out. All these tests have been carried out as per ASTM standard. The solid particle erosion test clearly indicates that the composite behavior is semi-ductile in nature. There are other fabrication techniques available like injection moulding, compression moulding and extrusion, where the volume fraction of reinforcement can be increased. In addition, there are other chemical methods by which the fiber surface modification could be carried out. This work can be further extended to those techniques. However, the results reported here can act as a starting point for both industrial designer and researchers to design and develop polymer matrix composite components using Eulaliopsis Binata fiber as reinforcement. The whole dissertation has been divided in to seven chapters to put the analysis independent of each other as far as possible. Major works on mechanical characterization, moisture absorption characteristics, abrasive and erosive wear characteristics of EB-epoxy composite is given in chapter 3, 4, 5, and 6 respectively.