| abstract |
The present invention relates to a biocompatible, hydrophilic, segmented block polyurethane copolymer which comprises 5 to 45 wt% of a hard segment, preferably a reaction product of an organic diisocyanate, a diamine and a polyol, and 95 to 55 wt% of a soft segment selected from a hydrophilic, hydrophobic and amphipathic oligomer such as aliphatic polyols, aliphatic and aromatic polyamines and mixtures thereof; the copolymer being capable of forming a non-porous, semi-permeable film of a tensile strength greater than 300 and up to 10,000 psi, an ultimate elongation greater than 300 % and up to 1,500 %, and a water absorption such that the sum of the volume fraction of absorbed water and the hydrophilic volume fraction of the soft segment exceeds about 100 % and up to about 2,000 % of the dry polymer volume and being permeable to cell nutrients and waste molecules of up to about 6,000 to 600,000 molecular weight and substantially impermeable to cells and particulate matter. A non-porous, semi-permeable, biocompatible film is formed from the block copolymer of the invention in the form of a flexible sheet or a hollow fiber. The present invention also relates to a method of permeating molecules of a predetermined molecular weight range while preventing the passage of larger molecular weight molecules, cells and condensed phases of matter between two fluids comprising interposing between the two fluids the non-porous film of the invention. |