Composite Powder Using Porous Silicon to Prevent CNF Aggregation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cellulose nanofiber-supporting inorganic powders face challenges in uniform dispersion due to aggregation, leading to inadequate reinforcement of CFRP, rubber, and resin compositions.
Innovation Solution
A composite powder is manufactured by mixing cellulose nanofibers with a silicon-based porous material, such as diatomaceous earth or zeolite, with a controlled content ratio and dispersion method to ensure uniform dispersion, adhering to or inserting the nanofibers within the porous material's pores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cellulose nanofibers are mixed with rubber or resin using conventional methods, then reinforcement effect is achieved, but uniform dispersion is difficult due to aggregation
Solution Approach 1:
The patent uses silane coupling agents as intermediary substances to facilitate the interaction between hydrophilic cellulose nanofibers and hydrophobic rubber or resin matrices. The silane coupling agent forms a bridge between these incompatible materials, enabling uniform dispersion while maintaining reinforcement effects.
Solution Approach 2:
The patent modifies the surface properties of cellulose nanofibers through silane treatment, changing their hydrophilicity to enhanced hydrophobicity. This parameter change in surface chemistry enables better compatibility and uniform dispersion in hydrophobic rubber or resin matrices.
2Ease of manufacture
If cellulose nanofibers are dispersed in aqueous solution and dried, then powder form is obtained, but aggregation occurs during drying process
Solution Approach 1:
The silane coupling agent acts as a mediator during the drying process, preventing direct contact and aggregation between cellulose nanofibers. It maintains separation and uniform distribution even as the aqueous solvent evaporates and the material transitions to powder form.
Solution Approach 2:
The silane coupling agent creates a protective layer or coating around the cellulose nanofibers, essentially creating a modified version that maintains the original nanofiber structure while preventing aggregation during the drying and powder formation process.
3Adaptability or versatility
If hydrophobized pulp is used as raw material, then thermoplastic resin mixing is enabled, but melting point is restricted below cellulose decomposition temperature
Solution Approach 1:
The silane coupling agent enables the use of thermosetting resins as matrix materials by facilitating compatibility between hydrophobized cellulose nanofibers and the resin system. This intermediary approach allows access to higher temperature processing windows of thermosetting resins without direct contact between cellulose and extreme temperatures.
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 composite powder achieves uniform dispersion, preventing aggregation and enhancing the strength of CFRP, rubber, and resin compositions.
Implementation Method 1
the cellulose nanofibers at least adhere to a surface of the silicon-based porous material or are inserted in pores of the silicon-based porous material
Data Source
Figure 1~2
Figure 3
AI summary
A method includes: preparing a dispersion liquid by mixing a silicon-based porous material into an aqueous solvent in which cellulose nanofibers are dispersed; producing a dried material by drying the dispersion liquid; and producing a composite powder by grinding the dried material. A content ratio of the cellulose nanofibers and the silicon-based porous material in the dispersion liquid is 1:5 to 1:20 on a mass basis. A relationship of the following expression (1) is satisfied, [Math. 1] Y≤−0.048X+1.96 where X (in parts by mass) is a content of the silicon-based porous material relative to 1 part by mass of the cellulose nanofibers contained in the dispersion liquid and Y (in % by mass) is a concentration of the cellulose nanofibers.