Surface composition and protein adsorption of polyurethane membrane

Membranes of uncomplexed polyurethanes (PUs) were prepared by hydroxyl-term inated 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 fibr inogen 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 o f 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 di spersed on the surface. Frequency difference (Delta v) and shiftment, hydro gen bonding index (HBI) and glass transition temperature difference (Delta T-g) as a measure of phase homogeneity and the average strength of interpol ymer hydrogen bonds were utilized to study the change of surface compositio n and intermolecular interaction of the prepared PUs. The effect of hard se gment content, cupric chloride content on the surface composition and F/A m olar ratio were investigated. (C) 1999 Elsevier Science B.V. All rights res erved.