Novel Polyisobutylene-Based Polyurethanes with Unprecedented Combinations of Mechanical Properties Chemical Stability and Biocompatibility

摘要

Conventional polyurethanes (PUs) exhibit excellent combinations of mechanical properties, however, limited oxidative/hydrolytic/biological stability. We developed novel polyisobutylene (PIB)-based PUs having mechanical properties similar to those of commercial PUs together with unprecedented chemical stability. Our achievement was guided by increased insight into the structure/morphology/property relationship of PUs, and by our ability to control (i) hard/soft phase compatibility, (ii) hard phase stiffness versus flexibility, and (iii) the nature of H-bonding. For example, we precision synthesized PUs by using 4,4'-methylene-bis(cyclohexyl isocyanate) (HMDI)/1,6-hexanediol (HDO) hard segments and PIB/poly(hexamethylene carbonate) (PC) soft co-segments that exhibited ～31MPa tensile strength, ～600% elongation and resistance to 35% HNO_3; under the same conditions, Elast-Eon? (PDMS-based PU) and Bionate? (PC-based PU) degraded severely. PUs containing exclusively PIB soft segments in conjunction with novel chain extenders also exhibit excellent mechanical properties and chemical-biological resistance. We propose that the presence of chemically resistant PIB soft segments protect vulnerable other constituents (i.e., bring about superior chemical stability) and yield biocompatible surfaces.