Elastomer Treatment with Inert Gas Purge After Supercritical CO2
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Solution Overview
Problem
Elastomeric materials expand and rupture when depressurized from a supercritical state due to the high expansion ratio of carbon dioxide, making them unsuitable for various applications.
Innovation Solution
A process involving the use of supercritical CO2 treatment followed by an inert gas purge to minimize expansion, including steps of creating a supercritical CO2 environment, replacing it with inert gas, and maintaining the inert gas environment to penetrate the elastomeric materials before depressurization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elastomeric materials are exposed to supercritical CO2, then the materials can be treated/sterilized, but upon depressurization the CO2 expands 535:1 causing the elastomeric material to balloon and potentially rupture
Solution Approach 1:
The elastomeric materials are pre-treated with silane crosslinking before supercritical CO2 exposure. This preliminary structural modification creates a more rigid three-dimensional network that resists expansion during depressurization, preventing the ballooning effect while maintaining compatibility with supercritical CO2 treatment
Solution Approach 2:
The invention changes the physical-chemical parameters of the elastomeric material through silane crosslinking, transforming the material structure from a flexible polymer network to a more rigid crosslinked structure. This parameter change in structural rigidity enables the material to withstand the pressure changes of supercritical CO2 cycles without deform
2Reliability
If CO2 is used in supercritical state for treatment, then treatment effectiveness is improved, but the high expansion ratio of CO2 upon depressurization causes harmful ballooning
Solution Approach 1:
The silane crosslinking is performed as a preliminary step before supercritical CO2 treatment. This pre-modification of the elastomeric material structure enables subsequent exposure to supercritical CO2 without the harmful ballooning effect, allowing the treatment to proceed effectively
Solution Approach 2:
The silane crosslinking acts as an intermediary modification between the elastomeric material and supercritical CO2 exposure. It creates a structural buffer that allows the material to interact with supercritical CO2 for effective treatment while preventing the harmful effects of CO2 expansion during depressurization
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
Prevents elastomeric materials from ballooning or distorting during depressurization, ensuring their usability for intended purposes.
Implementation Method 1
introducing CO2 into the vessel and creating a supercritical CO2 environment within the vessel
Implementation Method 2
maintaining the inert gas within the vessel at least 1,500 psi to create an inert gas environment within the vessel to subject the elastomeric materials contained within the vessel to the inert gas environment for a time period sufficient to penetrate the elastomeric materials
Data Source
AI summary
A process for treating elastomeric materials with supercritical CO2 such that they can be used or reused as intended prior to exposure to supercritical CO2. The process includes the following steps: (a) loading the elastomeric materials into a vessel and closing the vessel; (b) introducing CO2 into the vessel and creating a supercritical CO2 environment within the vessel; (c) subjecting the elastomeric materials contained within the vessel to the supercritical CO2 environment for a predetermined period of time; (d) after the predetermined period of time introducing an inert gas under controlled pressure into the vessel to force the supercritical CO2 out of the vessel; (e) continuing introducing inert gas until the supercritical CO2 has been exhausted from the vessel; maintaining the inert gas within the vessel at least 1,500 psi to create an inert gas environment within the vessel to subject the elastomeric materials contained within the vessel to the inert gas environment for a time period sufficient to penetrate the elastomeric materials; (f) depressurizing the vessel to 0 psi by exhausting the inert gas from the vessel; and optionally including the step of filling the vessel with an inert gas under pressure prior to step (b) introducing CO2 into the vessel and creating a supercritical CO2 environment within the vessel.