EP-4177300-B1 - MULTI-STAGE FOAM SOUND-ABSORBING BLACK BODY MATERIAL, AND PREPARATION METHOD THEREFOR

EP4177300B1EP 4177300 B1EP4177300 B1EP 4177300B1EP-4177300-B1

Inventors

XU, ZHEN
PANG, Kai
GAO, CHAO
LIU, Xiaoting

Dates

Publication Date: 20260506
Application Date: 20220413

Claims (1)

A preparation method for a multi-stage foam sound-absorbing black body material comprising the steps of: immersing the polymer foam into a 10mg/ml aqueous 20µm graphene oxide dispersion for 2 hours, adding the obtained dried foam in 30% hydrazine hydrate for foaming for 2 h, and natural drying after foaming to obtain the sound-absorbing black body foam material, wherein the polymer foam is melamine foam with a thickness of 20 mm.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a Continuation Application of PCT Application No.PCT/CN2022/086668, filed on April 13, 2022, which claims the priority of Chinese Patent Application No. 202110398409.3, filed on April 14, 2021. TECHNICAL FIELD The invention belongs to the technical field of functional materials, and particularly relates to a preparation method for a multi-stage foam sound-absorbing black body material. DESCRIPTION OF THE PRIOR ART Sound-absorbing materials are widely used and play an important role in many fields, such as personal protection, electrical protection and architectural design. About 1/5 people around the world are suffering from hearing impairment and the number is growing rapidly. Therefore, it is very important to explore acoustic sound-absorbing materials having high performance. As a traditional sound-absorbing material, polymer foams have been widely used in various fields because of their highly porous structure, and the basic principle of its sound-absorbing property depends mainly on the friction of sound waves inside the porous holes to produce attenuation. At present, many researches have been carried out to optimize the sound-absorbing performance of polymer foams by controlling the pore size and the pore structure thereof, but the traditional materials are difficult to meet the increasing acoustic requirements. By adding functional nanomaterials such as graphene, carbon nanotubes, nanofibers and the like to the polymer foam, the sound-absorbing performance can also be enhanced. However, the sound-absorbing performance increased by the addition of nano-fillers is based on the increase of the contact area between sound wave and skeleton, thereby further increasing the friction loss of sound wave. Essentially, there is no fundamental breakthrough in sound absorption. Graphene was discovered in 2004 by Konstantin Novoselov and Andre K. Geim from the University of Manchester, England. It is a monatomic layer structure of graphite, with a regular hexagonal network and a honeycomb-like two-dimensional structure of sp2 hybrid carbon atoms, showing many charming characteristics. In the field of nanomechanical vibration, graphene has a low in-plane rigidity and a thickness of a monatomic layer, so that the resulted graphene drums can generate a greater out-of-plane deformation, with an obvious resonance effect from low frequency to ultra high frequency. Therefore, it is an ideal candidate to ultilize its vibration effect to attenuate the sound wave. However, graphene drums as an acoustic absorbing material still exists some disadvantages. First, ultra-thin graphene drums are difficult to be assembled into macroscopic materials for daily use. Although the aerogel can assemble the graphene of nanometer thickness in the three-dimensional porous material, the sheets with a poor connection therebetween are not fixed to form the nanographene drums, so that sheet slippage are likely to occur when vibrating, affecting its sound-absorbing ability. Further, due to the high cost of graphene, it is still not ideal to use graphene alone for large-scale production. By directly fixing the sheets of graphene inside the polymer foam, graphene tends to pile up layer by layer, which seriously breakdowns the ultra-thin vibration characteristic of graphene. Therefore, there are still great challenges in the preparation of new sound-absorbing materials with high performance. CN107652624 discloses a preparation method for a composite material comprising a three-dimensional porous melamine foam as a matrix uniformly loaded with graphene. The invention provides a composite material using polymer foam and graphene drum to improve the sound-absorbing performance significantly and can be used as an acoustic black body. By embedding the graphene oxide into the polymer foam, and then using solvent plasticizing and foaming technology to achieve the foaming of graphene oxide in the foam walls, thereby forming an ultra-thin graphene drum structure, fully utilizing the vibration characteristic of graphene drum on the commercial foam. Not only the black body material obtained has the best sound-absorbing effect and the widest sound-absorbing frequency by now, but also the method is simple and the cost is low, which is conducive to the large-scale application of the sound-absorbing black body in daily life. SUMMARY OF THE DISCLOSURE The invention provides a preparation method for a multi-stage foam sound-absorbing black body material comprising the steps of:immersing the polymer foam into a 10mg/ml aqueous 20 µm graphene oxide dispersion for 2 hours, adding the obtained dried foam in 30% hydrazine hydrate for foaming for 2 h, and natural drying after foaming to obtain the sound-absorbing black body foam material, wherein the polymer foam is a melamine foam with a thickness of 20 mm. The preparation method enables to provide a multi-stage foam sound-absorbing black body material