Low-Temperature Compression for Porous Monolithic Materials
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Solution Overview
Problem
Existing methods for manufacturing porous monolithic materials, such as those based on hydroxyapatite and other minerals, often result in materials with degraded chemical structures and unsatisfactory mechanical properties due to high-temperature sintering processes, which also limit the incorporation of organic components and homogeneity.
Innovation Solution
A process involving the formation of a mixture with a solvent, typically water, followed by isostatic compression at low temperatures to form ice crystals, which acts as a template for consolidating the powder into a monolith without heat-induced structural changes, allowing for the incorporation of organic components and achieving high mechanical resistance and homogeneous porosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-temperature sintering is applied to manufacture porous monolithic materials from mineral powder, then the material achieves structural consolidation, but the chemical structure of the mineral raw material is modified (partial elimination of oxygen atoms and hydroxides), degrading biocompatibility
Solution Approach 1:
The invention changes the temperature parameter from high-temperature sintering to low-temperature freezing, and changes the consolidation mechanism from thermal diffusion to ice crystal template formation. The mixture is frozen at low temperature to form ice crystals that template the porous structure, then lyophilized to remove ice, achieving consolidation without high-temperature exposure that would modify the chemical structure
Solution Approach 2:
The invention utilizes the phase transition of water from liquid to solid (freezing) to create ice crystals that serve as a temporary template. The ice crystals form a structured framework during freezing, which is then preserved through lyophilization to create the final porous structure, avoiding the need for high-temperature sintering that would alter the mineral's chemical composition
2Strength
If high-temperature sintering is applied to manufacture porous monolithic materials, then the material achieves structural consolidation, but organic raw materials cannot be incorporated before sintering as they would be decomposed by heat treatment
Solution Approach 1:
The invention changes the processing temperature from high-temperature sintering to low-temperature freezing and lyophilization. This parameter change allows organic materials to be incorporated into the mixture before freezing, as the low temperatures preserve organic integrity while still enabling porous structure formation through ice crystal templating
Solution Approach 2:
The invention performs preliminary mixing of organic materials with the mineral powder and solvent before freezing. This preliminary action allows organic components to be uniformly distributed in the mixture before the freezing process creates the porous structure, ensuring both structural consolidation and preservation of organic materials
3Ease of manufacture
If conventional sintering or additive manufacturing with laser heating is applied, then porous monolithic materials are manufactured, but the localized heating equivalent to high-temperature heating degrades the material structure
Solution Approach 1:
The invention replaces thermal heating processes with a phase transition-based process. Instead of using laser heating or sintering to create pores, the invention uses freezing to form ice crystals as templates, then lyophilization to remove them. This phase transition approach achieves porous structure formation without thermal degradation of the material composition
4Volume of stationary object
If water is frozen to form ice crystals as porogen, then porous structure is created, but the resulting material is very brittle and requires gelling agents that reduce mechanical strength
Solution Approach 1:
The invention replaces the need for gelling agents with a mechanical consolidation process. After freezing creates the ice crystal template and porous structure, high pressure is applied to densify and consolidate the material, providing mechanical strength through compression rather than through chemical gelling that would compromise the porous structure
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 process preserves the chemical structure and mechanical properties of the starting material, enabling the production of monolithic materials with enhanced mechanical strength and uniform porosity, while allowing for the incorporation of organic components, thus overcoming the limitations of previous methods.
Implementation Method 1
followed by isostatic compression at low temperatures to form ice crystals
Implementation Method 2
isostatic compression at low temperatures to form ice crystals, which acts as a template for consolidating the powder into a monolith
Data Source
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AI summary
The invention relates to a method for producing a porous monolithic material from at least one powder, preferably mineral, said method comprising at least one step of low-temperature compression of a mixture based on powder and at least one solvent, preferably water. The materials produced by said method have improved mechanical properties compared to the prior art materials. The materials for medical application, such as hydroxyapatite, also have improved biocompatibility compared to the prior art materials. The invention also relates to the materials produced by said method.