Graphene Drum Foam Structure for Wideband Sound Absorption

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Solution Overview

Problem

Existing sound-absorbing materials, particularly those using polymer foams enhanced with graphene, face challenges such as poor assembly, high cost, and loss of ultra-thin vibration characteristics, limiting their performance and scalability.

Innovation Solution

A method involving immersion of polymer foam in a graphene oxide dispersion followed by foaming with a hydrazine hydrate solution to create a multi-stage foam structure with graphene resonant cavities, enhancing sound absorption through friction and resonance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional sound-absorbing materials are used, then sound absorption performance is achieved, but flame resistance and structural stability deteriorate

Engineering Contradiction:
Improvesound absorption performanceVSAvoidflame resistance and structural stability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent uses composite materials by combining polyurethane foam with inorganic flame-retardant materials (such as aluminum hydroxide, magnesium hydroxide, or titanium dioxide) to create a material that simultaneously achieves sound absorption performance and flame resistance. The composite structure allows the organic foam to provide acoustic properties while the inorganic additives provide thermal stability and fire resistance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs porous materials by creating a foam structure with controlled pore sizes and distributions. The porous structure of the polyurethane foam allows sound waves to penetrate and be absorbed, while the pore architecture contributes to structural stability and can be designed to resist collapse under thermal stress.

Inventive Principle:
Principle #31Porous materials

2Reliability

If flame retardants are added to improve fire resistance, then flame performance is improved, but material homogeneity and processing difficulty worsen

Engineering Contradiction:
Improveflame performanceVSAvoidmaterial homogeneity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by distributing flame-retardant additives locally within specific regions or layers of the foam material rather than requiring uniform distribution throughout the entire material. This approach allows flame resistance to be achieved in critical areas while maintaining overall material homogeneity and ease of processing.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses parameter changes by optimizing the concentration, particle size, and distribution of flame-retardant additives to achieve the desired flame performance while minimizing impact on material homogeneity. By carefully controlling these parameters, the material maintains both fire resistance and processability.

Inventive Principle:
Principle #35Parameter changes

3Strength

If foam density is increased to improve structural stability, then mechanical strength is improved, but sound absorption performance deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidsound absorption performance
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating regions of varying foam density within the material structure. Denser regions provide structural stability and mechanical strength, while less dense regions with larger pores maintain sound absorption performance. This spatial variation in density allows both requirements to be satisfied simultaneously.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses another dimension by controlling the three-dimensional pore structure and architecture of the foam rather than relying solely on bulk density. By optimizing pore size, shape, and connectivity in different spatial dimensions, the material achieves structural stability without sacrificing sound absorption capabilities.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method significantly improves sound absorption by 200-1000%, achieving high sound-absorbing coefficients across a wide frequency range, is cost-effective, and suitable for large-scale production.

Implementation Method 1

Multi-stage foam sound-absorbing black body material

Methodology Applied
Scientific EffectAcoustic absorption: Acoustic Absorption

Implementation Method 2

foam sound-absorbing black body material

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP4177300B1Multi-stage foam sound-absorbing black body material, and preparation method therefor
Publication Date: 2026.05.06 ZHEJIANG UNIV
  • EP4177300B1 patent drawingFigure 1~2
  • EP4177300B1 patent drawingFigure 3~5
  • EP4177300B1 patent drawingFigure 6~7

AI summary

In the present invention, a multi-stage foam sound-absorbing black body material is provided for the first time. A graphene aerogel is introduced into a commercialized polymer foam skeleton by using a solvent plasticizing and foaming technology, so as to embed ultra-thin graphene drums in the foam skeleton. When sound waves enter the foam black body, a large number of graphene drums generate a severe resonance effect, thereby rapidly achieving attenuation of the sound waves, and combined with the friction loss of the porous structure of the polymer foam on the sound waves, excellent sound-absorbing performance is achieved in a wide frequency range. The present solution is provided on the basis of commercialized foam materials, has a simple method, low costs, and the potential of wide industrial application.