Rubbery Composition Using Cellulose Nanofiber Interfacial Adsorption
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Solution Overview
Problem
Existing rubber compositions have low mechanical properties such as strength, elongation, and hardness due to poor compatibility between the rubber and cellulose, which limits their effectiveness in various applications.
Innovation Solution
Incorporating a cellulose nanofiber and a fluorene compound with a 9,9-bis(aryl)fluorene skeleton into a rubber composition, where the fluorene compound adheres to the surface of the cellulose but is not covalently bonded, allowing for improved dispersion and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cellulose is added as a reinforcing agent to rubber composition, then mechanical properties such as strength and rigidity are improved, but compatibility between rubber and cellulose is poor leading to low fracture properties
Solution Approach 1:
The patent uses silane-modified polybutadiene rubber as an intermediary substance between cellulose and rubber. This intermediate material has affinity for both cellulose and rubber, improving interfacial compatibility and reducing stress concentration at the interface, thereby resolving the contradiction between strength improvement and fracture property degradation
Solution Approach 2:
The patent creates a composite material system consisting of cellulose, silane-modified polybutadiene rubber, and other rubber components. This multi-component composite structure allows the synergistic combination of cellulose's reinforcing effect with the compatibility-enhancing properties of the silane-modified rubber, achieving both improved strength and maintained fracture properties
2Reliability
If chemically modified microfibril cellulose is used to improve fracture properties, then energy loss at the rubber-cellulose interface is reduced, but mechanical properties such as strength and elongation deteriorate due to low affinity
Solution Approach 1:
The patent changes the chemical parameters of the rubber component by using silane-modified polybutadiene rubber instead of conventional rubber. This parameter change modifies the surface properties and chemical affinity of the rubber, enabling better interaction with cellulose and achieving both improved fracture properties and maintained mechanical strength
Solution Approach 2:
The patent applies local quality modification by concentrating the silane-modified polybutadiene rubber at the cellulose-rubber interface. This localized modification creates a gradient structure where the interface region has enhanced compatibility properties while the bulk rubber maintains its original mechanical characteristics, resolving the contradiction between fracture properties and strength
3Strength
If a large amount of chemically modified microfibril cellulose is added to improve mechanical properties, then strength and elongation are enhanced, but various properties cannot be balanced
Solution Approach 1:
The silane-modified polybutadiene rubber acts as a mediator that enables effective stress transfer between cellulose and the rubber matrix at lower cellulose loadings. This intermediary function allows achieving target mechanical properties with reduced cellulose content, thereby maintaining balance among various properties such as processability, mechanical strength, and fracture resistance
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 combination of cellulose nanofiber and the fluorene compound enhances the mechanical properties of the rubber composition, including strength, elongation, and hardness, while maintaining a balanced composition.
Implementation Method 1
the fluorene compound adheres to the surface of the cellulose but is not covalently bonded
Data Source
AI summary
A rubbery composition is prepared by combining (A) a rubber component, (B) a cellulose, and (C) fluorene compound having a 9,9-bis(aryl)fluorene skeleton. The fluorene compound (C1) may be a compound represented by the following formula (1):wherein a ring Z represents an arene ring, R1 and R2 represent a substituent, X1 represents a heteroatom-containing functional group, k denotes an integer of 0 to 4, n denotes an integer of not less than 1, p denotes an integer of not less than 0. The rubbery composition has improved mechanical properties such as strength, elongation, and hardness.