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Environmental stress cracking (ESC) was replicated in vitro on Optim™ (OPT) insulation, a polydimethylsiloxane‐based polyurethane utilized clinically in cardiac leads, using a Zhao‐type oxidation model. OPT performance was compared to that of two industry standard polyether urethanes: Pellethane® 80A (P80A), and Pellethane® 55D (P55D). Clinically relevant specimen configurations and strain states...
Polyurethane biostability has been the subject of intense research since the failure of polyether polyurethane pacemaker leads in the 1980s. Accelerated in vitro testing has been used to isolate degradation mechanisms and predict clinical performance of biomaterials. However, validation that in vitro methods reproduce in vivo degradation is critical to the selection of appropriate tests. High temperature...
Segmented polyurethane (PU) block copolymers were synthesized using 4,4′-methylenediphenyl diisocyanate and 1,4-butanediol as hard segments and oligomeric ethoxypropyl polydimethylsiloxane (PDMS) as the soft segments, with hard segment contents ranging from 26 to 52 wt%. The microphase separated morphology, phase transitions, and degrees of phase separation of these novel copolymers were investigated...
In this paper we explore the temperature dependence of segregation of hard and soft segments of selected segmented polyurethane copolymers using synchrotron small-angle X-ray scattering (SAXS). The copolymers are composed of the same hard segments but three different soft segment chemistries, of particular interest in biomedical device applications. Hard segments are formed from 4,4′-methylenediphenyl...
Segmented polyurethane block copolymers were synthesized using 4,4′-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) as hard segments and various soft segments derived from poly(hexamethylene oxide) (PHMO) and poly(dimethylsiloxane) (PDMS)-based macrodiols and mixtures thereof. The microstructure and degrees of phase separation were characterized using a variety of experimental methods...
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