title: Extraction of polyurethane block copolymers: effects on bulk and surface properties and biocompatibility.
abstract: In order to study changes occurring in polyurethane block copolymers upon solvent extraction, a base polymer containing approximately 50% polyurethane hard segment based on 4,4'-bis(p-phenyl isocyanate), 1,4-butanediol, and poly(tetramethylene oxide) of MW 1000 was synthesized. Portions of this polymer were extracted using methanol, toluene, and acetone. Multidetector gel permeation chromatography was used to characterize the effect of extraction on molecular weight and molecular weight distribution. Extraction also affected bulk and surface properties and the blood compatibility as assessed using a canine ex vivo blood-contacting experiment. Extracted materials possessed a higher molecular weight than the base polymer and had narrower molecular weight distributions. Acetone extraction resulted in the polymer with the highest ultimate tensile strength. Contrary to expectations, the surface properties and blood compatibility of the material studied were affected minimally by extraction.
authors.affiliation: Department of Chemical Engineering, University of Wisconsin, Madison 53706.
authors.forename: T G
authors.initials: TG
authors.lastname: Grasel
authors.forename: D C
authors.initials: DC
authors.lastname: Lee
authors.forename: A Z
authors.initials: AZ
authors.lastname: Okkema
authors.forename: T J
authors.initials: TJ
authors.lastname: Slowinski
authors.forename: S L
authors.initials: SL
authors.lastname: Cooper
mesh_terms: D001672:Biocompatible Materials; D002152:Calorimetry, Differential Scanning; D002850:Chromatography, Gel; D007202:Indicators and Reagents; D008855:Microscopy, Electron, Scanning; D008968:Molecular Conformation; D011140:Polyurethanes; D013329:Structure-Activity Relationship; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D007202:Indicators and Reagents; D011140:Polyurethanes