Polyvinyl Alcohol Crosslinked Copolymer Water Release
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Solution Overview
Problem
Existing agricultural water-retaining materials, such as those based on polyacrylic acid hydrogels, suffer from low water release capacity and unstable water absorption, which limits their effectiveness in providing water to plants.
Innovation Solution
A polyvinyl alcohol-based crosslinked copolymer with specific structural units, including an unsaturated monocarboxylic acid-based structural unit, carboxylate-forming structural units, and a solubility of 90% or less, is developed to enhance water release and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a hydrogel of polyacrylic acid-based polymer is used as water absorbent resin, then water absorption capacity is improved, but water release capacity deteriorates and biodegradability worsens
Solution Approach 1:
The patent changes the chemical composition parameters by using polyvinyl alcohol as the base polymer instead of polyacrylic acid, and controls the carboxylate content at 1-35% by mole. This parameter change enables the resin to achieve both high water absorption capacity and improved water release capacity, while also being biodegradable.
Solution Approach 2:
The patent creates a composite structure by incorporating carboxylate-forming structural units (1-35% by mole) into the polyvinyl alcohol backbone. This composite approach combines the hydrophilic properties of polyvinyl alcohol with the water retention capabilities of carboxylate groups, achieving balanced water absorption and release properties.
2Object-affected harmful factors
If modified polyvinyl alcohol with carboxyl groups is used to improve biodegradability, then environmental compatibility is improved, but water release capacity deteriorates
Solution Approach 1:
The patent precisely controls the carboxylate content parameter within 1-35% by mole of total structural units. This optimized parameter range maintains biodegradability while preventing excessive water retention that would hinder water release capacity. The solubility is also controlled at 90% or less to achieve the desired balance.
3Quantity of substance
If crosslinking reactions proceed during drying process, then water absorption capacity is improved, but quality stability deteriorates
Solution Approach 1:
The patent introduces carboxylate-forming structural units into the polyvinyl alcohol structure before the drying and crosslinking process. This preliminary action ensures that crosslinking reactions occur in a controlled manner during drying, rather than irregularly, thereby maintaining quality stability while achieving adequate water absorption capacity.
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 polyvinyl alcohol-based crosslinked copolymer exhibits improved stability and a high water release capacity, allowing plants to absorb a greater amount of water, thus addressing the limitations of existing materials.
Implementation Method 1
a water absorbent resin composed of a modified polyvinyl alcohol copolymer having carboxyl groups and/or carboxylate groups
Implementation Method 2
having a high water release capacity such that a plant can absorb a greater amount of water
Data Source
AI summary
A polyvinyl alcohol-based crosslinked copolymer may include an unsaturated monocarboxylic acid-based structural unit, wherein an amount of carboxylate-forming structural units in the crosslinked copolymer is 1% by mole or more and 35% by mole or less with respect to all structural units constituting the crosslinked copolymer, and a solubility of the crosslinked copolymer in water is 90% or less.