P ractical 6

P ractical Theme Thermal property and inflammability of fabrics Task Burning test on various fabrics and analysis of its type Purpose of the Activity: Inflammability of fabrics will help to test the behaviour of fabrics in flame and while approaching flame. This will help consumer in taking special care when in use. This is also a way of identifying fibre content of fabrics which are in five composition. Heat affects different fibres in different ways. Some fibres scorch and flame, others melt and/or flame or shrink. Some fibres are self extinguishing, others are completely non-combustible. Burning Characteristics of Fibres Fibre Approaching flame In flame Removed from flame Odour Ash or residue Cotton and Linen Does not shrink, catches fire Burns quickly Continues burning, has an afterglow Burning paper Light, soft ash, retains shape Wool and silk Curls away from flame Burns slowly Self extin­ guishing Burning hair Brittle, curled, small amount, crushable ash Rayon Does not shrink, catches fire Burns quickly Continues to burn rapidly Burning paper Light, fluffy residue, very small amount Nylon Shrinks Melts, catches fire Continues melting Acrid Hard, tan coloured bead Polyster Shrinks Melts, catches fire Continues melting Plastic burn­ ing Hard, black coloured bead Acrylic Does not shrink, catches fire Burns rapidly with melting Continues burning Acrid Hard, black coloured, crinkly bead Conduct of the practical . Take a narrow strip of the fabric ( ½ cm X cm) . Hold the strip with a forceps or tongs and do the burning test by bringing it near a burning candle, or low flame of spirit lamp. Precaution Perform this experiment on a very low flame of a candle or spirit lamp under the supervision of a teacher. . Repeat the process by taking - samples of different fabrics and record the observations. Appro- aching flame In flame Removed from flame Odour Residue (colour and texture) Conclusion