Application of a TiO₂ 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.