Effect of Polyurethane Resin Addition on Acoustic Performance of Natural Coconut Coir Fiber

Abstract

During the last few years remarkable efforts were taken for the development of natural sound-absorbing material. Recent advances in acoustic materials lead to a variety of natural sound-absorbing materials like jute, arenga pinnata, hemp, corn husk, to name a few. This article speaks for the sound absorption characteristics of coconut coir fibers with polyurethane resin. Results of this study revel sound-absorbing characteristics of coconut coir fiber and polyurethane resin with the help of impedance tube setup as per ISO 10534–2 and ASTM E1050-98 standards for the frequency range 100–5000 Hz. The acoustic performance of coconut coir fiber is measured by the addition of polyurethane resin with varying weight percentages such as 10%, 20%, 30%, and 40%. The absorption coefficient of 0.95 is achieved at high frequency 3200 Hz for 40 mm thickness with 70% fiber and 30% resin composition without air gap which is comparable with many synthetic materials. Same sample exhibit better result in comparison with another sample for low and medium frequency region showing a sound absorption coefficient of 0.4 (100–500 Hz) and 0.81 (500–1900 Hz). Finally, alongside the effect of the air gap of 0 mm, 10 mm, 15 mm, 20 mm, and 30 mm on sound absorption coefficient were measured.

Keywords

• coconut coir fibers
• polyurethane resin
• sound absorption coefficient
• resin fiber composition
• air gap
• natural fiber material