Interlocked Porous Polymer via Freezing Demulsification
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Solution Overview
Problem
Existing methods for producing porous polymer materials face challenges such as poor control over pore structures, environmental concerns due to high-VOC waste water, and limitations in large-scale manufacturing and water resistance.
Innovation Solution
A method involving the freezing and demulsification of emulsions to produce interlocked porous polymer materials, which allows for easy adjustment of porous structures and is suitable for large-scale manufacturing, using emulsions containing uncrosslinked polymers and crosslinking agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional melt-blown fabrics are made from hot pressing of linear polypropylene fiber, then the mask can be produced, but the ability to control pore structures is poor and chemical disinfectants must be used which require more than a week for volatilization
Solution Approach 1:
The patent utilizes the phase transition of water from liquid to solid (freezing) to create a template structure. The frozen water forms ice crystals that, when removed, leave behind controlled porous structures in the polymer material. This eliminates the need for chemical disinfectants while achieving precise pore structure control.
Solution Approach 2:
Water in frozen form acts as an intermediary template that temporarily occupies space during manufacturing. After the polymer is formed around the ice crystals, the ice is removed (typically by melting or sublimation), leaving controlled pores. This intermediary approach enables precise pore control without requiring complex chemical processes.
2Manufacturing precision
If collodion is made by polyvinyl alcohol containing starch with dissolving sacrificial starch and crosslinking by formaldehyde, then porous collodion is obtained, but a large amount of high-VOC waste water is produced causing environmental protection issues
Solution Approach 1:
The patent replaces chemical crosslinking with formaldehyde with a physical phase transition process. Water is frozen to form ice templates, then the ice is removed through melting or sublimation. This physical process eliminates the need for formaldehyde and high-VOC waste water generation while achieving controlled porous structures.
Solution Approach 2:
The patent uses water as a temporary, disposable template that is easily removed after serving its purpose. The frozen water structure is intentionally designed to be temporary and removable, leaving behind the desired porous structure without generating harmful waste. This replaces the problematic formaldehyde crosslinking process.
3Manufacturing precision
If foaming elements are added to polymer matrix material to generate porous structure, then through-hole material is prepared, but the polymer body must have higher viscosity to fix the porous structure and control ability over pore structure morphology is low
Solution Approach 1:
The patent uses frozen water as an intermediary template that defines the pore structure during manufacturing. Because the ice crystals provide a rigid physical template, the polymer can be applied in a lower viscosity state and will conform to the ice template's shape. After the polymer sets, the ice is removed to reveal the controlled porous structure.
Solution Approach 2:
The phase transition of water to ice creates a stable, removable template that works with lower viscosity polymers. The ice structure maintains its shape during polymer application, allowing better pore morphology control without requiring high polymer viscosity. The subsequent removal of ice through melting or sublimation completes the process.
4Manufacturing precision
If traditional template and phase separation methods are used to prepare polymer through-hole materials, then porous materials are obtained, but the process flow is complicated and cannot meet large-scale manufacturing requirements
Solution Approach 1:
The patent uses a simple freezing process that can be easily scaled up. The phase transition of water to ice is a straightforward, controllable process that can be applied uniformly across large production volumes. This eliminates the need for complex multi-step template preparation and removal processes, enabling large-scale manufacturing while maintaining precise pore structure formation.
Solution Approach 2:
The frozen water template automatically forms the desired pore structure without requiring additional processing steps. The ice crystals naturally arrange themselves in a controllable pattern during freezing, and their subsequent removal through melting or sublimation is a simple, self-contained process. This self-service approach eliminates complicated process flows and enables efficient large-scale production.
5Manufacturing precision
If freezing casting method with water as solvent is used, then porous polymer through-hole material is obtained, but the material has poor water and weather resistance
Solution Approach 1:
The patent uses frozen water as a temporary template during manufacturing, but the final product is designed to be hydrophobic through material selection and surface treatment. The phase transition process creates the pore structure, while separate material engineering ensures water and weather resistance. The frozen template serves only the manufacturing function and does not compromise the final material's environmental resistance.
Solution Approach 2:
The patent applies different properties to different aspects of the material: the pore structure (created by frozen water template) provides the desired morphology, while the polymer matrix and surface treatment provide water and weather resistance. This local quality approach allows the material to have both controlled porosity and environmental resistance simultaneously.
6Reliability
If emulsion containing hydrophobic components is used to form porous materials by ice-templating process, then good water resistance is achieved, but the polymer must have high modulus or stiffness to support the porous structure which limits the method's development
Solution Approach 1:
The frozen water acts as a supportive intermediary template during the manufacturing process, providing structural support that allows the use of polymers with lower modulus or stiffness. The ice template bears the mechanical load during pore formation, enabling versatile polymer selection. After the process completes and the ice is removed, the final material maintains water resistance through its hydrophobic composition.
Solution Approach 2:
The phase transition of water to ice provides temporary structural support during manufacturing, enabling the use of a broader range of polymers including those with lower stiffness. The ice's rigid structure compensates for the polymer's lower modulus during the critical pore-forming stage. This allows greater adaptability in polymer selection while maintaining water resistance in the final product.
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 enables the production of porous polymer materials with controlled morphologies and properties, suitable for various applications, including filters and medical masks, while being environmentally friendly and scalable.
Implementation Method 1
freezing and demulsification of emulsions
Implementation Method 2
freezing will induce the aggregation of polymer which will make materials change into porous state after freezing drying
Data Source
AI summary
The present invention provides a method to prepare polymer materials with interlocked porous structures by freezing and demulsification, which includes: (1) Preparing an emulsion containing uncrosslinked polymers and crosslinking agents. The uncrosslinked polymers are presented in the organic phase, and the crosslinking agents are presented in the organic phase or water phase. Under freezing, the demulsification is occurred which leads to the interaction between polymers and crosslinking agents, and the crosslinked materials are obtained. (2) After removing the ice crystals, polymer materials with interlocked porous structures are synthesized. The method provided by the present invention is simple to operate, and can well adjust the porous structures of obtained porous polymer materials. In addition, it is suitable for large scale manufacturing. At the same time, this process can form different functional porous polymer materials by simply changing the used monomers. Particularly, it can prepare melt-blown fabrics with antibacterial property, high-throughput vertical porous structures and high-temperature sterilizable feature, therefore, it can be used to manufacture medical products such as masks.