http://www.nnin.org/sites/default/files/files/NNIN1014.pdf
cheers
PS from Graphene Tracker online,
HEAD’s new series of graphene-reinforced rackets are being promoted by the likes of Novak Djokovic and Maria Sharapova, with users reporting increased precision and ease of use, accompanied by decreased racket weight. In one of the early promotional videos, Novak’s new racket is called his “secret weapon”. The composition of the racket and the role of graphene was indeed secret, until the publishing of the graphene racket patent application.
HEAD chose to try and protect not only the use of graphene in rackets, but also in all other sporting goods, including skis, snowboards, golf clubs, and footwear. If the patent is approved with all its claims, it is sure to rake in large profits for HEAD, as other sporting goods manufacturers will certainly follow up with their own explorations of graphene. Strangely though, the patent application does not put a claim on balls made of graphene.
US patent application number 20130090193 describes the use of graphene as a reinforcing element in the build of a tennis racket. The graphene is embedded into an epoxy matrix, which makes at least a part of the racket’s structure. The use of graphene increases the racket’s performance, making it lighter in weight yet more durable than rackets used to date. The graphene also makes the racket’s stiffness along different directions more proportional, addressing a problem commonly experienced with non-graphene reinforced fibers. This means that tennis players will now have more freedom to throw their racket against the ground upon losing a point, knowing that graphene is there to help the racket survive and be used again.