Silane-Modified Silica Preparation via Aqueous Sol-Gel
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Solution Overview
Problem
Current silica modification methods face challenges such as high energy consumption, environmental pollution, and nonuniform modification due to the use of large amounts of organic solvents and stringent operating conditions, which affect the dispersibility and bonding performance of silica in rubber and polymer systems.
Innovation Solution
A sol treatment method using a silane coupling agent, where hydrolysis is performed with a catalyst, water, and solvent to create a stable sol solution, followed by ultrasonic dispersion and dehydration condensation with silica to achieve uniform modification, reducing the need for high temperatures and minimizing solvent usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If wet modification method is used to modify silica, then the modifying agent amount is small and cost is low, but large amounts of organic solvents are used making post-processing complicated and causing environmental pollution
Solution Approach 1:
The patent changes the solvent system from organic solvents to water as the continuous phase, creating a water-based sol-gel system. This parameter change eliminates organic solvent pollution while maintaining the low modifying agent requirement, as the silane coupling agent hydrolyzes and condenses in the aqueous environment to form a uniform coating on silica particles.
2Ease of manufacture
If dry modification method is used to modify silica, then the process is simple with high reaction efficiency, but stringent operating conditions and large amounts of modifying agent are required
Solution Approach 1:
The patent introduces a water-based sol-gel system as an intermediary medium between the silica particles and the silane coupling agent. The sol-gel process allows the coupling agent to hydrolyze and form a colloidal suspension that uniformly coats the silica surface, reducing the total amount of modifying agent needed compared to direct dry mixing methods.
3Ease of manufacture
If hot-pressing modification method is used to modify silica, then the process has simple post-processing, but high energy consumption and equipment requirements are needed
Solution Approach 1:
The patent replaces the thermal energy-intensive hot-pressing modification with a chemical sol-gel process that occurs at lower temperatures. The silane coupling agent undergoes hydrolysis and condensation reactions in the aqueous sol system, forming covalent bonds with silica surface hydroxyl groups without requiring high-temperature pressing equipment, thus reducing energy consumption while maintaining post-processing simplicity.
4Reliability
If conventional modification methods are used, then silica can be modified, but uniform modification is difficult to achieve due to agglomeration
Solution Approach 1:
The patent segments the modification process into distinct stages: (1) hydrolysis of the silane coupling agent in water to form silanol groups, (2) formation of a stable sol colloidal suspension, and (3) gradual addition of silica particles with ultrasonic dispersion. This segmentation prevents agglomeration and ensures uniform distribution of the coupling agent across all silica particle surfaces.
Solution Approach 2:
The patent applies ultrasonic vibration during the dispersion stage to break up agglomerates and ensure uniform distribution of silica particles in the sol-gel system. The ultrasonic energy creates cavitation and mechanical disruption that prevents particle clumping, leading to homogeneous modification across all particles.
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
This method results in silica with improved dispersibility and bonding properties, reducing energy consumption and environmental impact while maintaining mechanical properties, making the silica more suitable for high-filled applications and energy-efficient processing.
Implementation Method 1
a hydrolysis using a coupling agent, a solvent, water and a catalyst as raw materials is performed to prepare the sol solution of the coupling agent
Implementation Method 2
A uniformly-dispersed turbid solution is obtained through ultrasonic dispersion for over 1 h and 1-100 times under an ultrasonic frequency of over 20 kHz
Implementation Method 3
dehydration condensation of the silanol groups between the sol solution and silica is performed to obtain silica modified by the silane coupling agent
Data Source
AI summary
The invention relates to a method for preparing silica modified by a silane coupling agent and belongs to the fields of development and utilization of silica. The method comprises the following steps: preparing a kind of coupling agent sol solution by mixing the solvent, water, catalyst and coupling agent; uniformly dispersing silica into the sol solution by means of ultrasonic dispersion or shear dispersion to achieve a turbid solution with uniform dispersion and ideal particle size; and then stirring the turbid solution at a constant speed to make the coupling agent sol reacting with silica to prepare highly hydrophobic silica modified by the coupling agent through controlling the temperature and reaction time. In the invention, the coupling agent sol solution is obtained by a sol-gel process and silica is uniformly dispersed in the coupling agent sol solution through combined action of various dynamic means to ensure the sufficient reaction between silica and coupling agent, thus to obtain silica modified by the coupling agent. The method provided by the invention has the advantages of simple operation, saving energy, low cost, wide application and easy industrialization; and the obtained silica modified by the silane coupling agent has excellent properties.