ABSTRACT
This study investigated the absorptive properties of non woven cotton and Poly lactic acid materials. The non woven materials used in this study are batts and fabrics made from 100 percent cotton and 100 percent poly lactic acid fibers. These are biodegradable from natural source and are environmentally friendly. The fibers were characterized for their properties by subjecting them to different characterization tests. Twenty samples were produced from the fibers using the non woven processing. Layering was achieved by tacking layers of batts in various sequences of 100%, 75%, 50% and 25% of batts respectively to form blend ratios of the fibers of 800g/m2 area weights (eight layers). The method used for measuring the acoustical properties of the samples is the impedance tube method whereby; sound absorption coefficient is determined at each of the eleven frequency range in accordance with the ASTM 1050 - 08 standards; which tested five specimens from each sample. Both fiber types achieved good absorption, but the results obtained show that eight (8) layers cotton batts absorbed better than cotton fabric and PLA batts and fabric, since its absorption coefficient is closest to one. The results also show that physical parameters such as; fiber type, size, density, cross section, are significant to level of absorption. These parameters and other variables such as: thickness, resistance, layering order, porosity and air permeability were all investigated and their influence on material absorption is found to be positive and significant. This study suggests that these fibers (cotton and PLA) which are environmentally friendly and cost effective will serve as good alternatives to petroleum based fibers which are currently in use.