EVALUATION OF HOT- GAS AND HEATED TOOL WELDMENTS OF POLYPROPYLENE/BONE PARTICULATE COMPOSITES

Thesis Overview

<p> </p><div><div><b>1.0 INTRODUCTION</b></div><div>The development of many technologies that make our existence so comfortable depends largely on the availability of suitable materials (Callister, 2007). However, most of these technologies require a material with unusual combination of properties (e.g. high specific strength, magnetic–transparent, conductive–transparent, catalytic–magnetic, huge yet invisible to human eye and so on), which indeed exceed the domain of our conventional metal alloys, ceramics, polymers, heat treatments etc (Luigi and Gianfranco, 2005;Hanemann and Vinga 2010).Nevertheless, the use of compositesas another class of engineering materials has proven to be vital and a promising candidate in the areas of these advanced technologies. Other answers to these contemporary developments include bio-technology, nanotechnology to mention a few.</div><div><br></div><div>Composites &nbsp;were &nbsp;developed &nbsp;to &nbsp;improve &nbsp;on &nbsp;the &nbsp;properties &nbsp;(strength &nbsp;to &nbsp;weight &nbsp;ratio, &nbsp;good</div><div><br></div><div>corrosion resistance, thermal stability etc) of a monolithic material so that it could be used in</div><div><br></div><div>sophisticated areas such as aviation (where high specific strength is desired), marine (where low</div><div><br></div><div>weight and high corrosion resistance guaranty safety), sporting equipment (where less weight is</div><div><br></div><div>appreciated), and many other applications which include high performance rocket-motor and</div><div><br></div><div>pressure vessels (Harris, 1999).</div><div><br></div><div>Composites are made up of primarily two major individual materials referred to as constituent materials. These constituent materials are termed as matrix and reinforcement. At least one portion of each type is required. The matrix material surrounds and supports the reinforcement materials by maintaining their relative positions; while the reinforcements impart their special mechanical and physical properties to enhance the matrix properties. The net effect is thus an attainment of a material with a unique combination of properties not common to either the matrix or the reinforcement (Matthews and Rawlings, 2005; Callister 2007). The common matrices used include metals/alloys, ceramics and polymers while the reinforcement can be in form of fibre (short or continuous) or particulate reinforcement (Hull and Clyne, 1981).</div><div><br></div><div>Depending on the matrix and the reinforcement used in composite formulation, properties of the composite are indeed direct interpolation of its constituents’ properties. As a consequence,thermoplastic composites display appreciable properties which are known to be inherent features of their matrices (Matthews and Rawlings, 2005). In line with this, thermoplastic reinforced composites enjoy high demand with increased interest to developing.....</div></div><br> <br><p></p>