Characterization of earplugs based on porous polyurethane (PU) and polyvinyl-chloride (PVC) polymers for human ear protection

Abstract

Personal ear protection (PEP) is a device designed to reduce the effects of ambient noise on humans, thus limiting the risk of hearing damage. This damage mainly affects the entire auditory chain (from the tympanic membrane to the cochlea). The aim of this work is to carry out a study of the mechanical properties of the PEP studied to model it subsequently using the finite elements method (FEM). To this end, the aim of this paper will be the study of the morphological and mechanical performance of porous polymers to protect the human ear from vibrations. The influence of air content (Porosity rate, pore size and shape) on the elastic matrix and mechanical properties of porous polymers (Young's modulus and Poisson's ratio) produced from available commercial Polyurethane (PU) and Polyvinyl-Chloride (PVC) were examined and discussed. The authors present a mathematical model that is able to predict the Young’s modulus of porous polymers as a function of matrix characteristics, mechanical excitation and porosity percentage. Porosimeter, Scanning Electron Microscope (SEM) and Light Microscope (LM) techniques are used for morphological characterizations. PU and PVC earplugs are effective for sound reduction, so they can be used for other applications.