CHAPTER 5. Flame Retardant Characteristics of Natural Fibre Composites

There is an increasing need for more environmentally-friendly composites, both in terms of the raw materials used and the end of life disposal methods. The concept of using natural fibres as reinforcing elements dates back to prehistoric times when straw or animal hair was used to reinforce mud houses, later used as reinforcement in bricks. In recent years there has been a renewed interest in these fibres due to their biodegradable nature and hence, positive environmental impact. Fibres such as hemp, flax, jute, etc. are increasingly being used with synthetic thermoplastics (eg polypropylene, polyethylene etc), thermosets (unsaturated polyester, epoxy) or resins from natural sources. Fire resistance and smoke generation properties of composite materials are major issues these days because, depending on applications, they must pass some type of regulatory fire test in order to assure public safety. Thus, it is important to understand how individual components of the end-products burn and how best to modify materials to make them flame-resistant without compromising their uniquely valuable low weight to high mechanical property ratios. This chapter reviews the effect of different natural fibres on the thermal stability and flammability of thermoplastic/thermoset composites. Potential fire retardant solutions are also suggested.