Investigation on sound absorption coefficients of betel nut fiber reinforced polymer matrix composites

This research investigates the sound absorption coefficients of betel nut fibers (Areca Fibers) reinforced with thermoplastic (Polypropylene) and thermoset (Unsaturated polyester) matrix composites with different fiber loadings and frequencies. In this research we used 5%, 10%, 15%, and 20% of betel nut fibers in the polymer matrix and the test frequencies are from 400 Hz to 1800 Hz. There are two standardized methods used for measuring the normal incidence sound absorption coefficient of composites namely, standing wave method (ISO 10534-1) and two fixed microphone method (ISO 10534-2). From this research, betel nut fibers reinforced with polymer matrix composites have good sound absorption coefficients at high frequency although the overall sound absorption coefficient is quiet low. The Increase in fiber loading increases the sound absorption coefficients of composites. The types of polymer did not have significant influences on sound absorption coefficients. Both methods of measurement show the same results where the two fixed microphone method is much quicker than standing wave method