Green Sound-Absorbing Composite Materials of Various Structure and Profiling

Abstract

This article presents thermoplastic sound-absorbing composites manufactured on the basis of renewable raw materials. Both the reinforcing material and the matrix material were biodegradable and used in the form of fibers. In order to mix flax fibers with polylactide fibers, the fleece was fabricated with a mechanical system and then needle-punched. The sound absorption of composites obtained from a multilayer structure of nonwovens pressed at different conditions was investigated. The sound absorption coefficient in the frequency ranging from 500 Hz to 6400 Hz was determined using a Kundt tube. The tests were performed for flat composites with various structures, profiled composites, and composite/pre-pressed nonwoven systems. Profiling the composite plate by convexity/concavity has a positive effect on its sound absorption. It is also important to arrange the plate with the appropriate structure for the incident sound wave. For the composite layer with an added pre-pressed nonwoven layer, a greater increase in sound absorption occurs for the system when a rigid composite layer is located on the side of the incident sound wave. The addition of successive nonwoven layers not only increases the absorption but also extends the maximum absorption range from the highest frequencies towards the lower frequencies.

Sound Absorption Performance and Mechanical Properties of the 3D-Printed Bio-Degradable Panels

“…In recent times, with the development of modern industry and air and road traffic, noise has become one of the countless factors affecting human health and the environment worldwide. Noise has become a major problem that causes harmful effects on human health, and combating it requires urgently finding the best solutions through increasingly restrictive regulations and legislation [ 1 , 2 ]. Lately, the improvement of living conditions by regulating noise in the fields of aviation (by reducing the interior noise of passenger aircraft), railways, automobiles and buildings is a requirement forced on industrial companies [ 3 ].…”

Combined effects of linseed oil and heat treatment on the properties of cypress and maple wood Part 1: Water absorption, mechanical properties, and sound absorption capacity

“…Mineral-based sound insulation materials may pose a risk to human health because they contain mineral particles that can become airborne (Berardi and Iannace 2017). Synthetic materials may cause environmental pollution during their production and disposal (Yang et al 2020;Gliscinska et al 2021). Synthetic materials turn into micro plastics and pose risk especially to marine life and humans (Almroth et al 2018).…”

Influence of surface finishing of hardwood cross-section on sound absorption performance

“…Synthetic fibers are prone to break down into microplastics, which can pose a threat to marine life and humans who consume them (Almroth et al 2018). Thus, research of sound absorption solutions using eco-friendly (green) materials is active (Bhingare et al 2019;Yang et al 2020;Gliscinska et al 2021). Most green soundabsorbing materials are fibrous materials produced as agricultural by-products (Bhingare et al 2019;Yang et al 2020;Gliscinska et al 2021).…”

“…Thus, research of sound absorption solutions using eco-friendly (green) materials is active (Bhingare et al 2019;Yang et al 2020;Gliscinska et al 2021). Most green soundabsorbing materials are fibrous materials produced as agricultural by-products (Bhingare et al 2019;Yang et al 2020;Gliscinska et al 2021). Some of these materials have been reported to have sound absorption performance as good as that of commercial synthetic fibers (Lim et al 2018;Putra et al 2018), However, natural fibers are less durable than synthetic fibers and they are difficult to commercialize.…”