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Polymer Failure Analysis – Medical Device Performance |
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The Problem: A leading medical device manufacturer discovered performance problems in one of their products that posed life-threatening consequences. The problem centered on inconsistencies in the mechanical properties of the device. Initially, the device manufacturer was uncertain if the performance inconsistencies stemmed from a neoprene polymer provided by another company or their own compounding and fabricating processes. The unpredictable nature of the problem - one lot of devices would work perfectly while another lot would exhibit sporadic failures - undermined the root cause analysis. In fact, more than two years of cooperative efforts between the two companies failed to provide a solution. The inability of the two companies to resolve the problem prompted a call to ICI TechDirect to begin an independent investigation. |
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The Approach: Acting on the customer’s suggestion, ICI TechDirect’s scientists focused their initial analysis on the chemistry of the “good” and “bad” devices. They also saw the need - based on experience in hundreds of other failure analyses projects – for a thorough examination of several key properties and the internal structure of the device. After completing a thorough examination of the chemical composition of the device using FT-IR spectroscopy, Gas Chromatography-Mass Spectroscopy and Energy Dispersive X-Ray analysis, the TechDirect team measured the Tg of the base polymer by Differential Scanning Calorimetry (DSC), the polymer’s thermal stability by Thermogravimetry (TGA) and the internal micromorphology of the device by Scanning Electron Microscopy (SEM). |
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The Results: TechDirect scientists showed that there were only minor differences in the chemical composition of the “good” and “bad” medical devices. The features that distinguished good from bad instead appeared in the micro-morphology (microscopically visible structure) of the polymer used in making the devices. SEM examinations revealed
inhomogenieties in the device’s microstructure that appeared related to the polymer cure and more directly to the quality of the polymer’s dispersion during manufacturing.
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Problem solving sessions facilitated by TechDirect staff at the customer's manufacturing site revealed that the root cause of the performance inconsistencies stemmed from poorly controlled processing conditions and changes in the type of neoprene used in device’s manufacture. Once the problem was identified and brought under strict control limits, the variability of the polymer’s internal morphology disappeared completely and, more importantly, the product’s performance remained consistent. |
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For further information on ICI TechDirect's thermal analysis services so that you can create your own success story, click here. |
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