SYNTHESIS AND CHARACTERIZATION OF NEW HYDROPHOBIC POLYURETHANES FOR BIOMEDICAL APPLICATIONS

The synthesis of new segmented polyurethanes containing as chain extender N-hexadecyl-2,2-bis(hydroxymethyl)propionamide (alone or with 1,4-butanediol at different mole ratios) is described. The degree of hydrophobicity and the glass transition temperatures T(g) were found to be proportional to the alkyl chain content of the polymers. Also the amount of bonded albumin is proportional to the alkyl group content of the polymer, and platelet adhesion is remarkably lower for the 100% alkylated polymer (PEUHDA) than for the standard non-alkylated polyurethane (PEU). This behaviour was confirmed by SEM evaluation, showing a much lower degree of activation of platelets on albuminized PEUHDA films. It was not possible to ascertain with sufficient reliability a different behaviour, with respect to platelet adhesion, of the polymers containing alkyl chains in the range 9 divided-by 50 mol%, due to the relatively high error of the evaluation systems.