Superabsorbent Polymer Composition for Stable Swelling Permeability
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Solution Overview
Problem
Existing super absorbent polymers face challenges in balancing high absorption rate and permeability due to issues with cross-linking, leading to degraded physical properties such as surface tension, permeability, and increased fine powder generation.
Innovation Solution
A polyacrylic acid-based super absorbent polymer with controlled slip strain, maintaining a constant slip strain of 12.5% or less at 30% swelling and an absolute rate of change in slip strain of 0.04 or less between 30% and 70% swelling, optimizing permeability and absorption rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If cross-linking polymerization is performed by including a foaming agent in a monomer composition to form a porous structure, then the surface area of the super absorbent polymer is increased, but the overall physical properties such as surface tension, permeability, and volume density are degraded
Solution Approach 1:
The patent removes the foaming agent from the monomer composition entirely, extracting the harmful element that caused degradation of physical properties. Instead of using a foaming agent to create porous structure, the invention relies on the natural swelling behavior of the cross-linked polymer network to achieve the desired surface area and permeability without compromising structural integrity.
Solution Approach 2:
The patent optimizes the cross-linking density parameter to achieve a balance between maintaining structural integrity and enabling sufficient swelling. By carefully controlling the cross-linking degree and network structure, the invention achieves both adequate surface area for absorption and maintained physical properties without requiring a foaming agent.
2Reliability
If the cross-linking density is controlled to be high to improve permeability, then the permeability is improved, but moisture absorption is hindered and centrifuge retention capacity is degraded
Solution Approach 1:
The patent optimizes the cross-linking density parameter to achieve a balance between maintaining structural integrity and enabling sufficient swelling. By carefully controlling the cross-linking degree and network structure, the invention achieves both adequate surface area for absorption and maintained physical properties without requiring a foaming agent.
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 polymer maintains excellent permeability and absorption rate throughout various stages of swelling, improving centrifuge retention capacity and reducing fine powder generation, while maintaining shape and absorption performance.
Implementation Method 1
a super absorbent polymer (SAP) is a synthetic polymer material which has the ability to absorb moisture 500 times to 1,000 times its own weight
Implementation Method 2
cross-linking polymerization is performed by including a foaming agent in a monomer composition, thereby forming a porous structure in base resin powder
Data Source
AI summary
A polyacrylic acid (salt)-based super absorbent polymer has a slip strain (%) of 12.5% or less after the polyacrylic acid (salt)-based super absorbent polymer is subjected to 30% swelling. The slip strain means a value at a time when a storage modulus rapidly decreases with an increase in strain when a change in the storage modulus is observed by increasing the slip strain of each sample from 0.01% to 100% using a rheometer under a frequency of 1 Hz and a temperature of 25° C. The superabsorbent polymer has an absolute value of a rate of change in slip strain at 30% and 70% swelling derived by Equation 1 of 0.04 or less, wherein Equation 1 is Rate of change in slip strain at 30% and 70% swelling=[{(slip strain at 70% swelling)−(slip strain at 30% swelling)}/40].