TWI Industrial Member Report Summary 1003/2011
By I Jones and R Shepherd
Successful utilisation of materials for medical applications or, more generally, applications requiring adhesion often requires suitable surface treatment prior to application. Selection and application of an appropriate surface treatment is one of the major factors in achieving good wettability and improving long term durability, whereas, inadequate surface treatment is one of the most common causes of premature degradation and failure.
- Two application areas requiring surface engineering have been selected specifically for investigation in this work. One is the modification of polyetheretherketone (PEEK), which is regularly used in medical devices and implants which need to have well controlled surfaces for cell or other biological interaction. The other is modification of polypropylene (PP), which is traditionally difficult to bond because of its low surface energy. Focussing on one application (in the oil and gas sector) polypropylene is used extensively for the corrosion protection and insulation of floe lines. Individual sections of pre-coated pipe are joined by welding the steel substrate however; this welded joint is required to be coated to provide contiguous corrosion/insulation coatings - a field joint. Field joint infill materials are required to bond and provide good durability for the life of the pipeline. Improvement of PP bonding in this application has been a goal in the industry for sometime; satisfactory surface treatment would allow it to be used more effectively in the where PP is often bonded to polyurethane.
- If processing conditions are found that provide control over the surface properties, the principles may be applied in a wide variety of other areas.
To assess the effects of laser surface modification for:
- Alteration of the surface energy of PEEK for medical implants and microfluidic devices.
- Improvement of adhesion between PP and itself and PU in particular for insulated oil and gas pipelines, when compared to untreated surfaces.