Surface composition and protein adsorption of polyurethane membrane

Membranes of uncomplexed polyurethanes (PUs) were prepared by hydroxyl-terminated polybutadiene (HTPB), 4,4'-dicyclohexylmethane diisocyanate (H12MDI) and 1,4-butane diol (1,4-BD). While complexed PUs were prepared by using N-methyl diethanol (MDEA) as the chain extender of which the tertiary amines were complexed with cupric ions. Molar ratio of protein adsorption of fibrinogen to albumin (F/A molar ratio) on polymer surface was measured. The F/A molar ratio was affected by surface composition. The surface composition was identified by ESCA measurement and quantified by the absorption ratio of carbonyl group to butadiene group (C=O/C=C ratio) on the FTIR-ATR spectra. Low F/A molar ratio and high contact angle were found on these PUs. The F/A molar ratio was decreased by the increase of soft segment or C-H bond dispersed on the surface. Frequency difference (Delta v) and shiftment, hydrogen bonding index (HBI) and glass transition temperature difference (Delta T-g) as a measure of phase homogeneity and the average strength of interpolymer hydrogen bonds were utilized to study the change of surface composition and intermolecular interaction of the prepared PUs. The effect of hard segment content, cupric chloride content on the surface composition and F/A molar ratio were investigated. (C) 1999 Elsevier Science B.V. All rights reserved.