Fabrication of Millable Polyurethane Elastomer/Eucommia Ulmoides Rubber Composites with Superior Sound Absorption Performance

• Published in: Materials 2021-12, Vol.14 (23), p.7487
• Main Authors: Dong, Yuhang, Yin, Dexian, Deng, Linhui, Cao, Renwei, Hu, Shikai, Zhao, Xiuying, Liu, Li
• Format: Article
• Language: English
• Subjects: Absorbers (materials); Absorptivity; Acoustic absorption; Composite materials; Crystallization; Damping; Deformation; Elastomers; Frequency ranges; Mechanical properties; Microstructure; Noise control; Noise pollution; Polyurethane resins; Rubber; Scanning electron microscopy; Sound; Sound transmission; Storage modulus; Vibration
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma14237487

Sound absorbing materials combining millable polyurethane elastomer (MPU) and eucommia ulmoides rubber (EUG) were successfully fabricated via a physical blending process of EUG and MPU. The microstructure, crystallization performances, damping, mechanical and sound absorption properties of the prepared MPU/EUG composites were investigated systematically. The microstructure surface of various MPU/EUG composites became rough and cracked by the gradual incorporation of EUG, resulting in a deteriorated compatibility between EUG and MPU. With the increase of EUG content, the storage modulus (E') of various MPU/EUG composites increased in a temperature range of -50 °C to 40 °C and their loss factor (tanδ) decreased significantly, including a reduction of the tanδ of MPU/EUG (70/30) composites from 0.79 to 0.64. Specifically, the addition of EUG sharply improved the sound absorption performances of various MPU/EUG composites in a frequency range of 4.5 kHz-8 kHz. Compared with that of pure MPU, the sound absorption coefficient of the MPU/EUG (70/30) composite increased 52.2% at a pressure of 0.1 MPa and 16.8% at a pressure of 4 MPa, indicating its outstanding sound absorption properties.