title: Polydimethylsiloxane/polyether-mixed macrodiol-based polyurethane elastomers: biostability.
abstract: A series of four thermoplastic polyurethane elastomers were synthesized with varying proportions of poly(hexamethylene oxide) (PHMO) and poly(dimethylsiloxane) (PDMS) macrodiols. The macrodiol ratios (by weight) employed were (% PDMS:% PHMO) 100:0, 80:20, 50:50 and 20:80. The weight fraction of macrodiol in each polymer was fixed at 60%. The mixed macrodiols were reacted with 4,4'-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) chain extender. The biostability of these polymers was assessed by strained subcutaneous implantation in sheep for three months followed by microscopic examination. Pellethane 2363-80A and 2363-55D were employed as control materials. The mechanical properties of the polymers were tested and discussed along with the biostability results. The results showed that soft, flexible PDMS-based polyurethanes with very promising biostability can be successfully produced using the mixed macrodiol approach. The formulation with 80% PDMS macrodiol produced the best result in terms of a combination of flexibility, strength and biostability.
authors.affiliation: The Cooperative Research Centre For Cardiac Technology, University of New South Wales, Graduate School of Biomedical Engineering, Sydney, Australia.
authors.forename: D J
authors.initials: DJ
authors.lastname: Martin
authors.forename: L A
authors.initials: LA
authors.lastname: Warren
authors.forename: P A
authors.initials: PA
authors.lastname: Gunatillake
authors.forename: S J
authors.initials: SJ
authors.lastname: McCarthy
authors.forename: G F
authors.initials: GF
authors.lastname: Meijs
authors.forename: K
authors.initials: K
authors.lastname: Schindhelm
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry*; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004355:Drug Stability; D004548:Elasticity; D008855:Microscopy, Electron, Scanning; D011140:Polyurethanes / Q000138:chemical synthesis / Q000737:chemistry*; D012828:Silicones / Q000737:chemistry*; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D004129:Dimethylpolysiloxanes; D011140:Polyurethanes; D012828:Silicones; C090631:polyhexamethylene oxide; C013830:baysilon