Patent ID: 7335697

Claim:
A method for producing a polymer composition, the method comprising the steps of: (a) providing a preform comprising ultrahigh molecular weight polyethylene having a weight average molecular weight of about 400,000 atomic mass units or more, (b) providing a solution comprising at least one non-polar biocompatible lipid selected from the group consisting of squalane, squalene, fatty acids, glycerides, cholesterol, cholesterol esters, and mixtures thereof, (c) contacting at least a portion of the preform with the solution to swell the ultrahigh molecular weight polyethylene and diffuse the non-polar biocompatible lipid into at least a portion of the preform, and (d) irradiating at least the portion of the preform contacted with the solution in step (c) to cross-link at least a portion of the ultrahigh molecular weight polyethylene contained therein and form a polymer composition comprising a matrix of cross-linked polyethylene molecules having a free volume, wherein the at least one biocompatible lipid fills at least a portion of the free volume of the matrix.