title: Synthesis, characterization and ex vivo evaluation of polydimethylsiloxane polyurea-urethanes.
abstract: A series of segmented polydimethylsiloxane (PDMS) polyurea-urethanes was synthesized based on hexane diisocyanate modified polyether-PDMS soft segments. The hard segments consisted of 4,4'-methylene diphenylene diisocyanate, which was chain extended with 1,4-butanediol. The effect of chemical composition of the polyether-PDMS soft segments on the extent of phase separation, physical properties and surface properties was studied using a variety of techniques including dynamic mechanical analysis, tensile testing, X-ray photoelectron spectroscopy (XPS) and contact angle analysis. The polymers were also evaluated for their blood-contacting properties in a canine ex vivo model. The PDMS polyurea-urethanes containing polyether-PDMS soft segments showed three distinct phases: a PDMS-rich phase, a polyol soft segment-rich phase and a hard segment-rich phase. The tensile strength and modulus of these materials were not significantly lower compared to a polymer without PDMS in the soft segment. XPS revealed the surface enrichment of the hydrophobic PDMS component at the air-solid interface. Dynamic contact angle measurements indicated that the PDMS-based polyurea-urethanes possessed a hydrophobic surface in water. The PDMS polyurea-urethanes showed lower adherent platelet and fibrinogen deposition compared to a polymer without PDMS in the soft segment. Varying the amount of PDMS in the soft segment of these polymers did not reveal significant differences in their blood-contacting properties.
authors.affiliation: University of Wisconsin-Madison, Department of Chemical Engineering 53706.
authors.forename: F
authors.initials: F
authors.lastname: Lim
authors.forename: C Z
authors.initials: CZ
authors.lastname: Yang
authors.forename: S L
authors.initials: SL
authors.lastname: Cooper
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry*; D001696:Biomechanical Phenomena; D001769:Blood; D004129:Dimethylpolysiloxanes / Q000138:chemical synthesis / Q000737:chemistry*; D004285:Dogs; D005340:Fibrinogen / Q000378:metabolism; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011140:Polyurethanes / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D013057:Spectrum Analysis; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D004129:Dimethylpolysiloxanes; D011140:Polyurethanes; D005340:Fibrinogen; C044690:polyetherurethane urea