Metal on Metal Hip Implants
J&J Depuy, maker of the Ultamet Metal-on-Metal acetabular hip system, has announced that they will no longer market this and related metal-on-metal products after August 31st. Since around 2007, the use of metal-on-metal has been in steady decline due to concerns about metal ion release and its possible association with pseuodo tumour formation in some […]
MIT Polymer Day
MIT held its annual MIT Polymer Day in March. Cambridge Polymer Group was a sponsor, and also supplied two judges for the poster contest, where students and post-doctoral research fellows presented their work on polymer technology. Link to PPST
Crystallinity in Peek
Polyether ether ketone (PEEK) is finding its way into more and more medical devices, due to its high strength, resistance to oxidation, bioinertness, and ease of manufacturing. PEEK is a semi-crystalline thermoplastic, and the crystallinity is strongly dependant on the processing conditions used to form a PEEK component, such as molding and cooling temperatures, sample […]
Polymers and Plastics in Medical Devices
Cambridge Polymer Group researcher Gavin Braithwaite will be presenting his work on hydrogels used in medical devices at the upcoming Polymers and Plastics in Medical Devices conference held in San Francisco, CA from June 26-28th, 2013. Dr. Braithwaite’s work discusses injectable hydrogels for nucleus pulposus and tissue augmentation, as well as cartilage replacement technologies. Link […]
HFIP Quantification
Hexafluoroisopropanol (HFIP), also known as hexafluoro-2-propanol, is a fluorinated alcohol commonly used in processing of polyethylene terephthalate, polyacrylonitriles, some polyketones, and polyamides. It is a fairly toxic material, causing several eye damage and respiratory problems. Consequently, manufacturers who use HFIP need to measure how much residual HFIP remains in their processed goods, particularly if the […]
A Peek at Peek
On September 25-26, 2013, an international symposium on polyetherether ketone (PEEK) will be held at Drexel University. PEEK is finding increasing use in the biomedical community, particularly in the area of permanent implants. Spinal implants have been composed of PEEK for several years, finding use as stabilization rods, spacers, and articulating surfaces. Characterization of PEEK […]
Fatigue Crack Propagation
Fatigue crack propagation (FCP) analysis is a method to monitor the resistance of a material to crack inception and propagation under cyclical loading. ASTM E647 describes the methodology for measuring crack propagation in materials. An example of the typical data obtained in FCP analysis is shown above for GUR 1020 UHMWPE subjected to ionizing radiation […]
Consolidation Defects in UHMWPE
Ultra high molecular weight polyethylene (UHMWPE) is the most commonly used bearing surface in hip and knee arthroplasties. Due to its high molecular weight, UHMWPE cannot be injection molded or extruded with a screw extruder. Compression molding or ram extrusion are the two consolidation processes used for UHMWPE, whereby the combination of temperature and pressure […]
Analysis of Vitamin E Residues
The increasing prevalence of Vitamin E, a naturally-occuring antioxidant, in medical grade plastics has resulted in a need for analysis methods that can track the effect of processing on this compound. Vitamin E is effective as an antioxidant due to the hydroxyl group sitting on the aromatic ring at one end of the molecule. This […]
ASTM Meeting on Medical Plastics
The ASTM Committee on Medical Devices (F04) met last week in Atlanta, GA. Cambridge Polymer Group staff attended several of the task groups, and reported back the following activities. Medical Device Cleanliness Several draft standards are in development, including guidance on cleanline validation, synthetic test soils to verify cleaning efficacy, guidance on how to design […]