Syndiotactic Polystyrene Nanoporous Packaging via Supercritical CO2
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Solution Overview
Problem
The production of nanoporous crystalline forms of syndiotactic polystyrene for active packaging in the food sector is hindered by the use of toxic and harmful solvents, making existing methods unsuitable for food contact materials.
Innovation Solution
A disordered nanoporous crystalline form of syndiotactic polystyrene is developed, characterized by specific X-ray diffraction peaks and prepared through a process involving conversion of commercially available α-form to amorphous form, treatment with non-toxic co-crystallizing agents, and removal of these agents, avoiding the use of harmful solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods using toxic solvents are used to produce nanoporous crystalline forms of syndiotactic polystyrene, then the nanoporous structure and gas absorption capability are achieved, but the materials become unsuitable for food contact applications
Solution Approach 1:
The invention extracts and eliminates the harmful toxic solvents from the production process by using supercritical carbon dioxide instead of conventional organic solvents. The supercritical CO2 serves as a green alternative that can be completely removed after processing, leaving no toxic residues in the nanoporous s-PS material, thus making it safe for food contact applications.
Solution Approach 2:
The invention changes the physical parameters of the processing medium by using supercritical carbon dioxide, which transitions from gaseous to supercritical state under specific pressure and temperature conditions. This parameter change allows CO2 to function as an effective solvent during processing while being environmentally benign and removable by simply returning to gaseous state, eliminating toxic contamination issues.
2Ease of manufacture
If toxic solvents are used in the manufacturing process, then the nanoporous crystalline structure can be formed, but the material becomes harmful for food packaging applications
Solution Approach 1:
The invention converts the potential harm of using solvents (environmental pollution and toxicity) into a benefit by selecting carbon dioxide as the solvent medium. CO2 is abundant, non-toxic, and environmentally friendly. The supercritical state of CO2 provides effective solvent capabilities for forming nanoporous structures, while its inherent safety profile eliminates the harmful effects associated with conventional toxic solvents.
Solution Approach 2:
The invention uses supercritical carbon dioxide as an intermediary medium that facilitates the formation of nanoporous crystalline structures without causing environmental harm. The supercritical CO2 acts as a temporary mediator during the phase transformation process, enabling crystal structure reorganization into nanoporous forms, and then is completely removed without leaving harmful residues.
3Manufacturing precision
If conventional solvent-based methods are used, then nanoporous forms can be obtained, but the process fails to meet food safety regulations
Solution Approach 1:
The invention extracts the harmful element (toxic solvents) from the manufacturing process and replaces it with supercritical carbon dioxide. The supercritical CO2 enables precise control over the crystalline form transformation into nanoporous structures through controlled pressure and temperature parameters, while being completely removable without toxic residues, thus achieving both manufacturing precision and food safety compliance.
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 process enables the creation of functionally active packaging materials that absorb volatile organic compounds, extending the freshness of food and plants by removing ethylene and carbon dioxide, while being environmentally friendly and compliant with food safety regulations.
Implementation Method 1
s-PS in the δ- and/or ε-forms is capable of absorbing in the crystalline phase (i.e. to form co-crystalline phases with), volatile organic compounds absorbed from liquid or gaseous mixtures
Data Source
AI summary
There is described a new disordered nanoporous crystalline form of syndiotactic polystyrene, characterized by a specific X-ray diffractrogram, the process for its preparation and various articles comprising this form of s-PS. This disordered nanoporous crystalline form exhibits empty crystalline cavities of nanometric sizes, and in this case performs the function of absorbing molecules with low molecular mass and is useful in particular as functionally active packaging for plant products.