THE EFFECT OF FIBRE CONTENT ON THE THERMAL AND FIRE PERFORMANCE OF POLYPROPYLENEGLASS COMPOSITES

摘要

Thermoplastic composites demand constant improvements in fire retardant and mechanicalproperties to fulfil their full market potential, especially in demanding sectors such as rail, aerospace andinfrastructure where fire performance is critical. The aim of this work is to understand the effect ofreinforcing fibres on flammability of polypropylene-glass (P-G) composites and means of improving theirfire performance in a cost effective manner. A number of polypropylene – glass composites with 0, 10and 20% (w/w) glass fibre have been prepared by co-extruding polypropylene and short length glassfibres and then hot-melt-pressing the pellets into plaques/laminates. The effect of fibre content on thethermal stability, flammability and mechanical performance of the polypropylene-glass without and inpresence of conventional fire retardants, has been studied. It has been observed that while the presence ofglass fibre lowers down the limiting oxygen index (LOI) value of the composite, the rate of flame spreadin a UL-94 equivalent test is also lowered. The reduction in LOI is due to the fact that glass fibre reducesthe melt dripping behavior of polypropylene (PP) and does not let the polymer (PP) move away fromflame, which then burns. Cone calorimetric study indicated that the glass fibre act as a thermal insulator,reducing the overall flammability of the composite laminate.