THE EFFECT OF FABRIC SCOURING ON FIRE AND MECHANICAL PERFORMANCE OF FLAME RETARDED FLAX/PP AND FLAX/PLA COMPOSITES

摘要

Natural fibre composites are becoming popular in automotive industry due to their biodegradability, renewability, and hence more environmental friendly properties [1-5]. However, natural fibres have low fire resistance, which has restricted their growth in applications where the fire regulations are stringent. Therefore, flame retardant (FR) treatments are required to improve their fire resistance. The common method of application of flame retardants to fabrics is to pad-dry and/or cure. Fabrics containing natural fibres, in particular cellulosics are usually scoured prior to any finish. This increases fabric wettability and hence pickup of the finish. Scouring usually removes sizing, hemicelluloses, lignin, pectin, waxes etc from cellulosic fibres. In composites, however the presence of lignin, pectin etc could be advantageous as they are reported to have better thermal stabilities than cellulosic structures [4,5]. However, not much is known about the effect of scouring on physical, mechanical and flammability properties of the composites. The aim of this work is to study the effect of scouring on the FR uptake levels of flax/PP and flax/PLA woven fabric, and fire and mechanical performance of composites prepared from these fabrics. For textile related applications flax fibres are usually scoured with sodium hydroxide (NaOH), sodium bi-carbonate (Na_2CO_3) or a detergent (sodium phosphate, Na_3PO_4) solutions prior to other treatments in order to remove the impurity present in the fibres, hence also resulting in improvement in the absorption of fibres for dyes and other finishes [6]. There is however, no literature available on the use/effect of these scouring agents on properties of hybrid fabrics such as flax/polypropylene (PP) or flax/polylactic acid (PLA). To study the effect of different scouring agents on hybrid fabrics, these scouring agents have been used at different concentrations. Mono-ammonium phosphate (AP), one of the commonly used flame retardants (FR) for cellulosic materials, has been chosen as a flame retardant for this study. The optimized scouring conditions for maximum FR pickup and minimum fibre mass loss were chosen to scour fabrics, which were then melt pressed to produce composite laminates.