Effect of eggshell as a filler on the mechanical properties of flexible polyurethane foam

Thesis Overview

<p> </p><p><strong>1.0 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</strong><strong>INTRODUCTION</strong></p><p>A brief review of the research work is given in this chapter.</p><p><strong>1.1 Background of the Study</strong></p><p>Solid foam is formed when gas is blown through solidifying plastic. Depending on its ability to retain original shape after compression, it can be classified as either flexible or rigid, Isa <em>et</em>&nbsp;<em>al.,</em>(2012). The foam can either be closed or open cell foams. In closed cell foams, the foam cellsare isolated from each other while the open cell foams are made up of broken cell walls, Babalola and Dominic, (2012).</p><p>Flexible polyurethane (PU) foam is one of the major productions from urethane material. Flexible polyurethane foams are used as cushioning material for automotive seat, mattress, furniture, and in packaging etc. According to Klempner and Sendijarevic (2004), flexible polyurethane material has become such widely usedbecause of its excellent light weight, strength to weight ratio performance and the most important is, it offers degree of comfort, protection and utility not matched by other single materials. This usefulness prompts the increase in the prices of polyurethane products consistently over the years which in turn necessitated the incorporation of variety of fillers into foam samples.</p><p>Also, the prices of flexible polyurethane foams are becoming increasingly high due to the high cost of raw materials (Onuegbu<em>et al.,</em>&nbsp;2010). The raw materials are mostly liquid reagents and chemicals obtained from petrochemicals and agro-products. The raw materials needed for the production of flexible polyether foam include polyol poly isocyanate, blowing agents, catalysts surfactants and additive such as fillers (Onuegbu<em>et al.,</em>&nbsp;2005).</p> <br><p></p>