Development and characterization of recycled high density polyethylene (rhdpe)/natural fibre composites

Project Abstract

<p> </p><p>Fiber-reinforced polymer composites have played a dominant role for a long time in a variety of applications for their high specific strength and modulus. The fiber which serves as a reinforcement in reinforced plastics may be synthetic or natural. This research focuses on natural plant and animal fibres (palm kernel, locust bean husk, goat fur and sheep wool). It deals with the production and characterization of composites of these fibres reinforced with recycled high density polyethylene. The physical properties such as density, water absorption and thickness swelling were determined. The tensile strength, flexural strength, hardness, impact energy, and wear properties were investigated. Thermal, chemical and microstructural analyses were also carried-out on the developed samples. The study revealed the result of the variation of the engineering properties with %wt composition of fibre reinforcements. It also presented the effect of variation of fibre length on engineering properties showing 10 mm as the critical length of fibres. The thermal analysis showed the destruction temperature range of the composites to lie between 400 and 500</p><p>&nbsp;</p> <br><p></p>

Project Overview

<p> 1.0 INTRODUCTION<br>1.1 Background of the Study<br>Over the last thirty years, composite materials, plastics and ceramics have been the dominant emerging materials but it is noted that the volume of different compositions and the number of applications of composite materials have been growing steadily, penetrating and conquering world markets relentlessly. Modern composite materials constitute a significant proportion of newly fabricated products ranging from domestic products to sophisticated products (Prakash, 2009; Hull, 1996).<br>Efforts to produce economical and attractive composite components have resulted in several innovative manufacturing techniques currently used in the composites industry. It is obvious, especially for composites, that the improvement in manufacturing technology alone is not enough to overcome the cost hurdle. It is essential that there be an integrated effort in design, materials processing, tooling, quality assurance, manufacturing, and even program management for composites to become competitive with metals. The use of composites has not been limited to aircraft industries but to other commercial applications in recent years. This is possible due to the introduction of new polymer resin matrix materials and high performance reinforcement fibers (Nayak, 2009; Prakash, 2009).<br>Natural fiber composites are emerging as realistic alternatives to glass-reinforced composites in many applications. Natural fiber composites such as hemp fiber-epoxy, flax fiber-polypropylene (PP), and china reed fiber-PP are particularly attractive in automotive applications because of lower cost and lower density. Glass fibers used for composites have density of 2.6 g/cm3 and cost between $1.30 and $2.00/kg. In comparison, flax fibers have a<br>2<br>density of 1.5 g/cm3 and cost between $0.22 and $1.10/kg (Joshi et al, 2004). While, natural fibers traditionally have been used to fill and reinforce thermosets, natural fiber reinforced thermoplastics, especially polypropylene composites, have attracted greater attention due to their added advantage of recyclability (Joshi et al, 2004). Natural fiber composites are also claimed to offer environmental advantages such as reduced dependence on non-renewable energy/material sources, lower pollutant emissions, lower greenhouse gas emissions, enhanced energy recovery, and end of life biodegradability of components.<br>As industry attempts to lessen the dependence on petroleum based fuels and products there is an increasing need to investigate more environmentally friendly, sustainable materials to replace the existing glass fiber and carbon fiber reinforced materials (Zampaloni et al, 2007). Therefore, attention has recently shifted to the fabrication and properties of natural fiber reinforced materials. The automotive and aerospace industries have both demonstrated an interest in using more natural fiber reinforced composites, for example, in order to reduce vehicle weight, automotive companies have already shifted from steel to aluminum and now are shifting from aluminum to fiber reinforced composites for some applications.<br>This has led to predictions that in the near future plastics and polymer composites will comprise approximately 15% of total automobile weight (Mohanty et al, 2002; Zampaloni et al, 2007). In this work, some natural fibers were utilized as reinforcement with HDPE waste using physico-mechanical and thermal property as criteria.<br>1.2 Problem Statement<br>Natural fibre reinforced polymer composites have raised great interest among material scientists and engineers in recent years due to the need for developing environmentally friendly materials, and partly replacing currently used glass fibers for composite reinforcement. Glass fibres are widely used to reinforce plastics due to their low cost and<br>3<br>fairly good mechanical properties. However, these fibres have serious drawbacks with respect to health and safety during handling and processing of fibre products. They can cause acute irritation of the skin, eyes and the upper respiratory tract. Concerns have been raised for long-term development of lung scarring (i.e., pulmonary fibrosis) and cancer. When released, glass fiber does not degrade and results in environmental pollution and threatens animal life and nature significantly (Neeraj and Geeta, 2013; Wambua et al., 2003).<br>1.3 The Present Work<br>It is against this backdrop (the stated problem) that the present research has developed and characterized recycled high density polyethylene (RHDPE)/Natural fiber composites: an alternative to conventional glass fiber reinforced composites.<br>1.4 Aim and Objectives<br>The aim of the present research is centered on the development and characterization of composites from recycled high density polyethylene (RHDPE) reinforced with plant fibre (locust bean husk and palm kernel) and animal fibre (sheep wool and goat fur). To achieve this aim, the following specific objectives are necessary:<br>i. To study the composition of the plant and animal fibres: palm kernel, locust bean husk, goat fur and sheep wool).<br>ii. To develop the composites using the polymer-fibre mix for each of the natural fibres.<br>iii. To study the mechanical and physical properties (tensile strength, flexural strength, hardness, impact energy, wear resistance, density, thickness swelling and water absorption) of the developed composites.<br>iv. To determine the effect of fibre length on the physical and mechanical properties of the developed composites<br>4<br>v. To study the microstructure of the composites using scanning electron microscope (SEM)<br>vi. To study the thermal properties of the developed composites.<br>1.5 Scope of the Study<br>The scope of this present research will be limited to the following areas:<br>i. Preparing the natural fibres and RHDPE prior to compounding.<br>ii. Formulation by varying the fibre amounts (5-25 wt %).<br>iii. Development of the composite by the compounding and heat pressing method.<br>iv. Testing the physical and mechanical properties of the developed composite.<br>v. Microstructural analysis of the developed composites.<br>vi. Thermal analysis of the developed composites.<br>vii. Comparative analysis of the natural fibers (plant and animal).<br>1.6 Significance of the Research<br>The new paradigm in the preparation of fiber reinforced composites is the use of natural fibers in place of petroleum-based synthetic fibers. Even though glass-fiber-reinforced composites have good mechanical properties, they exhibit shortcomings such as higher density, difficulty to machine, and poor recycling properties. Natural fibers have special advantages such as low cost, low energy consumption, low density, high specific mechanical properties, and non-abrasive and biodegradable properties when compared to synthetic fibers like glass. The use of natural fibers to make low cost and eco-friendly composite materials is a subject of green importance. <br></p>