Properties of modified hydroxyl-terminated polybutadiene based polyurethane membrane

Abstract

One hydroxyl-terminated polybutadiene (HTPB) based polyurethane (PU) solution was prepared by reacting equal equivalent of 4,4-methylene diphenyl diisocyanate (MDI) and HTPB with 1,4-butanediol (BDO) as chain extender. The PU was then cast into membrane. The kinetic of epoxidation of HTPB-based PU membrane by an in situ generated peracid method was studied by infrared spectroscopy. The epoxidized PU membrane was named as EPU. The other HTPB-based PU with different molar ratios of dimethyol propionic acid (DPA) and 1,4-BDO as chain extender were synthesized by solution polymerization. The present PU was then cast into a membrane and named as PUDPA. 1-Ethyl-3-(3-dimethyamino propyl) carbodiimide (EDAC) was used in the linking reaction to graft heparin to PUDPA to get heparin containing PUDPA membrane and named as PUDPA-Hep. The membranes were subsequently characterized by the Fourier transform infrared spectroscopy and electron spectroscopy for chemical analysis (ESCA). The properties of PU such as density and gas permeation test were measured. Wettability and protein adsorption on the membranes were also evaluated from the water content, contact angle, and protein adsorptions of fibrinogen and albumin on the PU membrane. The diffusion coefficient of water in the membrane was determined in accordance with the Fickian diffusion mechanism. By using Kaelble’s equation and the contact angle data, the surface energy of PU membrane was determined. The protein adsorption of fibrinogen and albumin on PU membranes was evaluated. It was found that oxirane content in the EPU membrane increased with epoxidation time. The surface energy of EPU and PUDPA membranes increased with the increasing of oxirane content and DPA content on the EPU and PUDPA membrane, respectively, whereas the contact angle decreased inversely. The surface tension of wet EPU and PUDPA membrane was higher than that of dry EPU and PUDPA membrane, respectively. The adsorption of albumin and fibrinogen decreased with increasing the degree of epoxidation and the DPA content, respectively. After heparin treatment, the contact angel and protein absorption on PUDPA-Hep were lower than those on PUDPA.