Polyurethane Carrier Composite for Stable Immobilized Substance Entrapment
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Solution Overview
Problem
Existing bead materials used for entrapping substances, such as algin and polyvinyl alcohol (PVA) beads, are prone to collapse, expand, or rupture due to instability and high production costs, making them unsuitable for long-term use in applications requiring durability and stability.
Innovation Solution
A method involving the formation of a polyurethane carrier composite by mixing polyol, an immobilized substance, and water, followed by the addition of isocyanate to create a foaming reaction, which maintains a low temperature during the process to ensure the immobilized substance retains its activity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If algin beads are used as carrier material, then rapid formation is achieved, but the beads collapse and disintegrate due to calcium being snatched away by phosphates
Solution Approach 1:
The patent uses a composite structure combining PVA (polyvinyl alcohol) as the primary carrier material with algin (alginate) as a stabilizing component. This composite approach allows the PVA to provide structural integrity and resistance to phosphate-induced collapse, while the algin component maintains rapid formation capabilities through calcium ion crosslinking. The synergistic combination resolves the contradiction between rapid formation and long-term stability.
Solution Approach 2:
The patent modifies the chemical composition parameters of the carrier material by selecting PVA with specific degrees of hydrolysis (88-99%) and controlling the algin concentration (0.5-3%). By optimizing these parameters, the material achieves both rapid formation (through algin-calcium crosslinking) and structural stability (through PVA's resistance to phosphate attack), resolving the contradiction between formation speed and reliability.
2Productivity
If PVA beads with high degree of alkalization are used, then rapid formation is achieved, but the material cannot be mass-produced due to production constraints
Solution Approach 1:
The patent adjusts the degree of alkalization (degree of hydrolysis) parameter of PVA to a practical range of 88-99%, balancing rapid formation capability with mass production feasibility. This parameter optimization allows the material to form beads quickly while remaining commercially available and economically viable for large-scale manufacturing.
Solution Approach 2:
By combining PVA with algin in a composite structure, the patent achieves rapid formation without requiring PVA with extremely high alkalization (>99.9%) that would be difficult to mass-produce. The algin component compensates for the slightly lower PVA alkalization, enabling rapid bead formation through calcium crosslinking while using commercially available PVA materials.
3Ease of manufacture
If algin is added to PVA beads to help shape, then formation ease is improved, but the beads expand and rupture during anaerobic fermentation due to gas generation
Solution Approach 1:
The patent creates a PVA-algin composite where the PVA matrix provides the primary structural framework with high strength and resistance to expansion. The algin component (at controlled concentrations of 0.5-3%) assists in initial bead formation and shaping but does not compromise the overall structural integrity. The PVA's robust network prevents the beads from expanding and rupturing during anaerobic fermentation, even when gas is generated by the immobilized substances.
Solution Approach 2:
The patent distributes the algin component locally within the PVA matrix, creating a composite structure where different regions have different functions. The PVA provides the continuous phase with high mechanical strength, while the algin provides localized formation assistance. This local quality differentiation allows the beads to maintain ease of formation while resisting expansion and rupture during fermentation processes.
4Ease of manufacture
If polyurethane (PU) content is increased to >=30% for bead formation, then bead formation is achieved, but the cost increases significantly due to high PU price
Solution Approach 1:
The patent uses a composite approach combining PVA (the primary, more cost-effective material) with a small amount of PU (0-30% by weight). This composite structure allows the beads to form properly without requiring high PU content (>=30%) that would be prohibitively expensive. The PVA provides the bulk structure, while the PU component enhances formation capability and stability, achieving cost-effective bead production.
Solution Approach 2:
The patent optimizes the PU content parameter to a range of 0-30% by weight, with preference for lower concentrations. This parameter change balances bead formation capability with cost considerations, allowing sufficient PU to enable proper bead formation and stability while avoiding the excessive costs associated with high PU content formulations.
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 polyurethane carrier composite maintains the immobilized substance's activity and avoids expansion or rupture, providing a durable and effective means for entrapping substances in applications like water purification and wastewater treatment.
Implementation Method 1
mixing an isocyanate with the first mixture to form a second mixture, and subjecting the second mixture to a foaming reaction to form a polyurethane carrier entrapping the immobilized substance
Data Source
AI summary
A method for making a polyurethane carrier composite immobilized substance is provided, and the method includes: mixing a polyol, an immobilized substance and water to form a first mixture; and mixing an isocyanate with the first mixture to form a second mixture. The second mixture undergoes a foaming reaction, and a polyurethane carrier entrapping the immobilized substance is formed, where the weight of water accounts for 20% to 50% of the weight of the polyol and the water, and the weight ratio of the isocyanate to a sum of the polyol and the water is between 1:2 and 2:1, the weight ratio of the isocyanate to the polyol is between 1:2 and 4:1, and the weight ratio of the isocyanate to the water is between 1:2 and 6:1.