Non-Shrinking Interpenetrating Polymer Composite via One-Pot Sol-Gel
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Solution Overview
Problem
The challenge in creating non-shrinking composite materials using sol-gel processes lies in the significant shrinkage of the inorganic phase during drying, which induces stress and limits the practical application of sol-gel monolithic composites, especially when the organic polymer is below its glass transition temperature.
Innovation Solution
A one-pot sol-gel method is employed, where a metalloid or metal alkoxide is alcoholyzed in a mixture of glycols or alcohols, followed by reaction with polymerizable monomers containing isocyanate groups, allowing for the formation of interpenetrating networks of inorganic and organic polymers without substantial shrinkage, using reactants that consume liquid by-products and avoid high-temperature drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional sol-gel drying process is used to form inorganic polymer network, then inorganic phase is formed, but significant shrinkage occurs inducing stress and limiting application
Solution Approach 1:
The patent combines the sol-gel process with free-radical polymerization in a one-pot method, merging inorganic network formation with organic polymerization. The organic polymer matrix forms simultaneously with the inorganic network, creating an interpenetrating structure that prevents shrinkage-induced stress and cracking during drying.
Solution Approach 2:
The invention creates a composite material system where an organic polymer matrix (formed via free-radical polymerization of monomers like acrylic acid or methacrylic acid) embeds and supports the inorganic sol-gel network. This composite structure accommodates volume changes and eliminates the harmful shrinkage effects observed in pure sol-gel systems.
2Stability of the object's composition
If high-temperature drying is applied to remove liquid by-products, then inorganic network consolidates, but cracking and dimensional limitations occur
Solution Approach 1:
The patent changes the processing parameters by conducting the sol-gel reaction and polymerization at lower temperatures (below the glass transition temperature of the organic polymer). This allows network consolidation without high-temperature drying, preventing cracking while maintaining dimensional stability.
Solution Approach 2:
The organic polymer matrix acts as an intermediary that supports the inorganic network during drying. The flexible organic phase accommodates volume changes and prevents stress concentration, eliminating cracking without requiring high-temperature treatment.
3Ease of manufacture
If reactants producing liquid by-products are used, then sol-gel reaction proceeds, but shrinkage and stress increase
Solution Approach 1:
The patent converts the harmful liquid by-products of the sol-gel reaction into useful components of the organic polymer matrix. The liquid monomers and oligomers that would normally be removed as by-products are instead polymerized to form the organic phase, eliminating shrinkage and stress while maintaining reaction progression.
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 approach results in high-yield, non-shrinking composite materials with minimal volume contraction (less than 10%), eliminating cracking and dimensional limitations, and producing homogeneous, transparent products with enhanced mechanical properties.
Implementation Method 1
a metalloid or metal alkoxide is alcoholyzed in a mixture of glycols or alcohols
Implementation Method 2
reaction with polymerizable monomers containing isocyanate groups, allowing for the formation of interpenetrating networks
Implementation Method 3
A one-pot sol-gel method is employed
Data Source
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AI summary
A composite including interpenetrating networks of an organic polymer, such as from an acrylate or olefin, having urethane groups; and an inorganic polymer, the composite having a low or no-shrinkage characteristic, and a method for making the composite, as defined herein.