Work

Development of Wool–Noil/ CWPU Composite Nonwovens With Enhanced Thermal, Mechanical, and Sound Absorption Properties

Year: 2026

Type: article

Abstract: ABSTRACT To address the poor low‐frequency sound absorption performance of traditional fibrous sound‐absorbing materials, this study prepared wool noil‐based multilayer composites by a lamination technique to enhance sound absorption and noise reduction. In the present work, the influence of the CWPU addition on the physical, thermal, and acoustic properties of the resulting nonwoven composite has been evaluated. Castor‐oil‐based waterborne polyurethane (CWPU) was synthesized utilized an acetone‐assisted technique, which is frequently applied to produce stable waterborne polyurethane dispersions with controlled viscosity and good reproducibility. The physical properties of the nonwoven composite, such as thickness, density, porosity, and air permeability, were analyzed for all samples in accordance with ASTM standards. The untreated WN sample exhibited a GSM of 1487.4 g/m 2 , 7.5 mm thickness, 0.198 g/cm 3 bulk density, and 84.8% porosity. WN/C05 and WN/C10 showed reduced bulk density (0.173–0.170 g/cm 3 ) and increased porosity (86.9%). FTIR confirmed successful CWPU formation through characteristic peaks at 1536 and 1235 cm −1 , indicating well‐developed urethane bonds. Furthermore, SEM analysis demonstrated that CWPU treatment kept the porous fiber network of the wool nonwoven intact, even at higher concentration, without causing pore collapse. CWPU addition allowed to improve thermal stability of the nonwoven composite. The WN sample exhibited the highest tensile strength (1.17 MPa) and elongation (60.92%). CWPU composites showed lower elongation (37.26%–53.79%) with similar tensile strength (0.94–0.95 MPa), indicating increased stiffness. The sound absorption coefficient was measured according to ISO 10534‐2 using the Impedance tube method. The incorporation of CWPU significantly improved the sound absorption coefficient of the nonwoven composite. Low CWPU improved low‐to‐mid frequency absorption, while high CWPU improved high‐frequency performance. NRC increased with CWPU concentration, with WN/C10 highest due to better fiber stabilization, optimized airflow, resistance, and greater energy dissipation.

Source: Journal of Applied Polymer Science

DOI: 10.1002/app.71419