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ABSTRACT
The consumption of polypropylene and polyester makes up over 50% by weight in the nonwoven industry and consequently the waste generated from them increases gradually every year. In this study, the polyester and polypropylene nonwoven selvages were recycled to produce functional composites. First, the two kinds of selvages were shredded and mixed in the proportion 1:1, and then stirred well. The functional sound absorption composites were produced by a compress molding technique with proper parameters. Sawdust was also added in the composites to investigate the influence of processing parameters and materials on the sound absorption efficiency of the composites. The sound absorption coefficients were measured according to ASTM E 1050 by an impedance tube. The results revealed that the average of the sound absorption coefficients increased with the thickness of the composites, but decreased with the density. The effect of adding sawdust to the sound absorption efficiency of the composites was not obvious from this work.
Among the applications of textiles, nonwovens are one of the fastest-growing segments of the textile industry and constitute roughly one-third of the fiber industry. The worldwide yield of nonwovens made of synthetic fibers was about 3.3 million metric tons in 2000. The polypropylene non woven sector is about 63 %, equal to 2.1 million metric tons, and the polyester sector is about 22.5 %, equal to 0.7 million metric tons. The consumption of nonwovens is about 0.13 million metric tons in Taiwan every year [10]. However, the waste generated from the nonwovens industry has increased gradually every year and caused many serious problems. Factories that manufacture nonwovens normally dispose of the selvages by burying and burning, often leading to environmental pollution and destruction. Recycling and reusing fibrous waste is one of the most important environmental tasks that face the world, to reduce environmental loading and promote the most effective use of resources.
Noise has become serious environment pollution in our daily life and is an increasing public health problem according to the World Health Organization's Guidelines for Community Noise. Noise can have the following adverse health effects: hearing loss; sleep disturbances; feel tiredness; cardiovascular and psychophysiologic problems; performance reduction; annoyance responses; and adverse social behavior. Therefore, it is very important to control or reduce noise from traffic,...