Application of a TiO 2 nanocomposite in earplugs: a case study of noise reduction.

BACKGROUND: Use of hearing protection devices has become necessary when other control measures cannot reduce noise to a safe and standard level. In most countries, more effective hearing protection devices are in demand.

OBJECTIVE: The aim of this study was to examine the effects of titanium dioxide (TiO2 ) nanoparticles on noise reduction efficiency in a polyvinyl chloride (PVC) earplug.

METHODS: An S-60 type PVC polymer as the main matrix and TiO2 of 30-nm size were used. The PVC/TiO2 nanocomposite was mixed at a temperature of 160 °C and 40 rpm and the samples were prepared with 0, 0.2 and 0.5 wt% of TiO2 nanoparticle concentrations.

RESULTS: Earplug samples with PVC/TiO2 (0.2, 0.5 wt%) nanoparticles, when compared with raw earplugs, showed almost equal noise attenuation at low frequencies (500-125 Hz). However, at high frequencies (2-8 kHz), the power of noise reduction for earplugs containing TiO2 nanoparticles was significantly increased.

CONCLUSIONS: The results of the present study showed that samples containing nanoparticles of TiO2 had more noticeable noise reduction abilities at higher frequencies in comparison with samples without the nanoparticles.