Modified Inorganic Filler Covalent Bonding for Rubber Durability
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Solution Overview
Problem
Existing methods for preparing modified fillers, such as silica, fail to achieve optimal properties due to hydrophobating agents not being covalently bound, leading to potential release during processing and compromised rubber compound properties.
Innovation Solution
A method involving an acidified aqueous slurry with an untreated inorganic filler, an emulsifier, and a hydrophobating agent, followed by washing and optional drying, to produce a modified filler with improved compatibility and binding of long chain silanes, enhancing the filler's compatibility with the polymeric matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hydrophobating agents are used to modify filler surfaces, then compatibility with polymeric matrix is improved, but the agents are not covalently bound and may be released during processing
Solution Approach 1:
The filler surface is modified with hydrophobating agents in advance during the preparation stage, creating covalent bonds before the filler is incorporated into the polymeric composition. This preliminary covalent modification ensures that the hydrophobating agents remain permanently attached to the filler surface throughout subsequent processing and service, eliminating the risk of release while maintaining compatibility with the polymeric matrix.
2Adaptability or versatility
If long chain silanes are used as hydrophobating agents, then filler compatibility with polymeric matrix is enhanced, but the agents are not covalently bound and can be released during processing
Solution Approach 1:
Long chain silanes are applied to the filler surface in advance and form covalent bonds during the preparation stage. This preliminary covalent attachment ensures that the long chain silanes remain permanently bound to the filler surface, preventing their release during subsequent processing operations while maintaining enhanced compatibility with the polymeric matrix.
3Strength
If fillers are incorporated into polymeric compositions to improve physical properties, then reinforcement is achieved, but the filler surfaces need modification to increase reactivity and coupling
Solution Approach 1:
The filler surface is pre-modified with hydrophobating agents that form covalent bonds during the preparation stage, creating reactive sites before the filler is incorporated into the polymeric composition. This preliminary modification enhances the reactivity and coupling between the filler and polymer matrix, facilitating better integration and improved physical properties without complicating the manufacturing process.
Solution Approach 2:
The chemical parameters of the filler surface are modified by introducing hydrophobating agents with specific functional groups that enhance reactivity. This changes the surface chemistry to promote better coupling with the polymeric matrix, improving the physical properties of the composite while maintaining ease of manufacture through straightforward covalent bonding mechanisms.
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 modified filler exhibits improved reinforcement, resulting in increased tear strength, hardness, and abrasion resistance of the rubber products, providing better mechanical durability.
Implementation Method 1
hydrophobating agents not being covalently bound, leading to potential release during processing
Implementation Method 2
an emulsifier, and a hydrophobating agent having the following structural formula (I)
Data Source
AI summary
Provided is a method for preparing a modified filler. The method includes in sequence providing an acidified aqueous slurry of an untreated inorganic filler which has not been previously dried; an emulsifier material; and a hydrophobating agent having the following structural formula (I):Ra−M-X(4−a) (I)wherein:R is C6 to C22 alkyl,M is silicon, titanium or zirconium,X is OR′ or halogen,R′ is C1 to C4 alkyl, anda is 1;washing and/or filtering the acidified aqueous slurry to obtain a modified filler; and, optionally, drying the modified filler. Polymeric compositions and articles also are provided.