I just got back from Dubai where I gave a keynote speech to the Gulf Coast Petrochemical and Chemical Association (GPCA) on the history of petrochemical research and process development. Plastics started making major inroads in substituting for traditional materials like glass, paper, cardboard, wood, and metals of various kinds. Thermosets like phenol-formaldehyde (think Bakelite) were followed by thermoplastics (Polyethylene, polypropylene,PVC, polystyrene), condensation products(polyamide, polyester resins) and, later, engineering resins ( ABS, polycarbonate, etc.) Even stronger, more “esoteric” high end plastics were synthesized and commercialized, but they were basically niche products. Now, one of these seems to be gaining a foothold.
Hardly anybody will remember that Imperial Chemical Industries(ICI), that storied British firm that lost its way and was eventually acquired by a large Dutch coatings firm, developed, in the 1970s, an extremely versatile high end plastics trade-named PEEK. It may be the only plastic that can meet or exceed the properties of metals, ceramics and thermoset composites, according to an article in the February 29th issue of Chemical and Engineering News. Accordingly, it sells for about fifty dollars per pound! For a while, the only source of PEEK, which is made from hydroquinone and difluorobenzophenone, was Victrex, which was spun off from ICI a number of years ago.
In addition to biocompatibility, this plastic retains its strength up to about 250 Centigrade, is flame retardant and has good electrical properties. So, when the attributes desired include corrosion or chemical resistance, structural strength and ability to operate at 150 Centigrade, PEEK ot other plastics in its family (aromatic polyketones or polyaryl ether ketones) may be the only materials suitable. And biocompatibility, together with structural strength, is helping to make this family of products a logical choice. So, for example, PEEK is now being used as a femur implant that lets bone grow around it. But the main uses for this family of polymer are in demanding applications for bearings, piston parts. pumps, valves and cable insulation in the aerospace, automotive and process industries. PEEK is readily machineable and produces plastic parts that are thermostable and electrically and thermally insulating. It is finding new uses in plastic extruders. Also, its desirable combination of corrosion resistance and structural strength is now bringing new applications in the offshore drilling market
In addition to Victrex, which is planning an expansion for its current 7000 tons/year capacity, several much larger chemical firms are becoming active in this area including Arkema, Celanese, Evonik and Solvay. And it is likely that PEEK will soon also be used in 3D printing applications. Companies are projecting a 70,000 tons/year global market, still very small compared to its predecessor plastics.