Environmental Simulation for Stability Testing of Polymeric Materials
Predicting Performance in Real-World Conditions
A material’s properties may change over time when exposed to specific environments. Understanding the extent and rate of these changes is essential for identifying potential issues and choosing materials that perform reliably in their intended environments. For example, while steel is an adequate material for most structural purposes, stainless steel is required for environments where rusting is a concern. Metals like these are relatively well understood, but polymers exhibit far more complex behaviors as they may undergo oxidation, hydrolysis, thermal degradation, mechanical degradation, chemical modification, or enzymatic degradation.
Accurate environmental simulation is a key component of stability testing, allowing us to assess how these materials will perform over time under application-specific conditions. When possible, the conditions of the simulated environment are enhanced to accelerate the effects of the environment, allowing prediction of future performance and helping to identify potential vulnerabilities. Correlating the accelerated conditions to real-time conditions is often challenging.
Types of Polymeric Materials CPG Tests
The nature and type of the polymer strongly impacts how it behaves in a specific environment, and therefore these environmental conditions must be selected carefully for each type of polymer and its intended application. We have performed environmental aging studies on:
- Rigid plastics
- Rubbers and elastomers, including silicone
- Seals and gasket
- Coatings and adhesives
- Hydrogels
- Composites
Key Testing Methods
Accelerated Aging
Accelerated aging tests, such as those conducted according to ASTM F1980, are often employed to simulate the long-term effects of environmental exposure on medical devices. These tests can help predict how materials will age over time, providing valuable insights into their durability and performance. However, they must be treated with caution if no real-time data is available to correlate the accelerated conditions to real-time behavior.
Oxidative Challenge Techniques
Following standards like ASTM F2003, F3336, or ISO 10993-13, oxidative challenge techniques are used to evaluate how materials respond to oxidative stress. This testing is particularly relevant for medical devices and other applications where materials are exposed to reactive environments.
Environmental Simulation Chambers
Environmental chambers allow precise control of parameters like temperature and humidity to simulate a wide range of conditions. Materials or products are challenged under different exposure environments, which can include simulated or exaggerated solution conditions (salt content, pH, polarity of solvent). Diffusion of species into or out of the material can have an impact on the aging process and therefore should be considered in the experimental design. When coupled with appropriate property testing, these simulations help determine how a material may change with environmental exposure, which helps ensure products made from the material can withstand application conditions.
Advantages of Environmental Simulation Testing
- Time-efficient evaluation of material behavior under various climatic conditions
- Ability to assess performance in extreme temperatures and humidity levels
- Determine impact of exposure to simulated solutions
- Identification of potential deficiencies in materials and products
- Ensure materials can withstand application environment conditions
Considerations for Testing
When selecting appropriate environmental simulation techniques, it is crucial to understand:
- The material’s degradation behavior
- Specific conditions the material will encounter in its intended environment
- Additives and components within the material that may be free to diffuse or change during processes
- Thermal properties of the material may mean the material itself changes if placed in too aggressive an environment.
For medical devices, simulants such as blood, dental soils, stomach fluid, and lipids can be used to replicate real-world conditions in a controlled, sustainable manner and hence reproducibly assess material compatibility and performance. Where possible, Cambridge Polymer Group uses published test method standards for environmental conditioning.
Importance of Comprehensive Testing
Polymeric materials should undergo rigorous stability testing for both shelf-storage and their intended application areas whenever possible. This comprehensive approach ensures that materials meet the required performance standards throughout their lifecycle.
By employing environmental simulation techniques, manufacturers can confidently develop and produce polymeric materials that maintain their integrity and functionality in even the most challenging environments.
Request a Custom Testing Protocol
Contact Cambridge Polymer Group to design a simulation plan matching your material’s operational environment.