The Acoustic Performance of Expanded Perlite Composites Reinforced with Rapeseed Waste and Natural Polymers

Silviu Nastac,Petronela Nechita,Cristian Simionescu,Carmen Debeleac,Mihai Seciureanu

doi:10.3390/su14010103

Abstract

Lignocelluloses residues from the post-harvest crop are receiving great scientific attention nowadays. Generally, the composite materials based on lignocelluloses waste present low density and weight, and better insulation properties compared with those petroleum-based. This study presents the results of experimental investigations regarding soundproofing capabilities for a composite material based on expanded perlite (EP) and natural polymers matrix (starch) reinforced with rapeseed stalks waste. The preparation of light-weight samples of composites was performed at room temperature through a mechanical mixing process of EP with starch polymers and rapeseed residues until optimum moisture content composition was obtained. Rapeseed stalks long fibers were avoided through the preliminary dry grinding procedure, and the composite was air-dried at room temperature for 48 h. Four samples of composites with different ratio of EP and rapeseed waste were considered. The evaluation of sample sound insulation characteristics was performed using the transfer-matrix method based on a four-microphone acoustic impedance tube. The paper concludes that the proposed composite provides comparative sound insulation capabilities to actual materials, with few particular aspects presented within the paper. Thus, these new materials are promising as a viable alternative to the actual large-scale utilization solutions in soundproofing applications.

Highlights

Received: 19 November 2021Currently, existing sound insulation materials are composed of petrochemical-based polystyrene or natural products of mineral origin, such as fiberglass and rock wool
The composite materials with expanded perlite matrix and corn starch polymer reinforced with rapeseed waste have been obtained at a laboratory scale
Depending on the rapeseed content in composite samples structure, these materials exhibit few particular aspects within their sound insulation characteristics, that the practical implementation has to consider the frequency spectrum of the source

Summary

Introduction

Existing sound insulation materials are composed of petrochemical-based polystyrene or natural products of mineral origin, such as fiberglass and rock wool. Keeping in mind the sustainability concerns, natural or recycled materials would be able to reduce the consumption of non-renewable resources and simplify the processes of reuse or recycling. There are indications that the materials based on renewable resources could compete with conventional materials, and the local availability of these materials could lead to a reduction of the economic and environmental impacts, mainly in the case of residues and by-products from agricultural and forestry industry [1]. Noise control is an important parameter to assure the environments with acoustical comfort. The utilization of materials with composite structures represents one of the most important factors in noise reduction. In order to meet the deficit between production and consumption, and to protect the environment without compromising the performance and quality of the product, recycling and waste recovery are considered viable solutions for the future [2]

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