title: Effect of processing route and acetone pre-treatment on the biostability of pellethane materials used in medical device applications.
abstract: Thermoplastic polyurethanes, such as Pellethane 2363 80A (Pel80A) and Pellethane 2363 55D (Pel55D) are widely used in the medical device industry because of their biological and mechanical properties. However, premature failure in such devices has been observed and attributed to environmental stress cracking (ESC). The current work investigates the possibility of reducing ESC via bulk morphology manipulation. This can be achieved through various processing routes such as solvent-casting (SC) and hot-press quenching (HPQ). The effect of stress on the bulk morphology of Pel55D and Pel80A was evaluated using small-angle X-ray scattering (SAXS) in conjunction with tensile testing. SC samples exhibited greater phase separation compared with HPQ samples. Alignment of hard segment domains became apparent around the point of yield. Onset of ESC with respect to SC and HPQ routines was determined using the Zhao-Stokes glass-wool test with optical (OM) and environment scanning electron microscopy (ESEM). Improvement in biostability of Pel80A was found in HPQ samples compared to those that were SC. A secondary objective of this work was to investigate the effect of acetone pre-treatment on surface morphology. High resolution imaging of acetone treated and untreated SC Pel80A showed significant differences in surface morphology.
authors.affiliation: Department of Materials Science, University of Cambridge, UK.
authors.forename: Jennifer Elizabeth
authors.initials: JE
authors.lastname: Taylor
authors.forename: Peter R
authors.initials: PR
authors.lastname: Laity
authors.forename: Sharlene
authors.initials: S
authors.lastname: Freeburn
authors.forename: Steven S
authors.initials: SS
authors.lastname: Wong
authors.forename: Keith
authors.initials: K
authors.lastname: Norris
authors.forename: Peck
authors.initials: P
authors.lastname: Khunkamchoo
authors.forename: Martin
authors.initials: M
authors.lastname: Cable
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Andrews
authors.forename: Anthony F
authors.initials: AF
authors.lastname: Johnson
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Cameron
mesh_terms: D000096:Acetone / Q000737:chemistry*; D001672:Biocompatible Materials; D001673:Biodegradation, Environmental; D001698:Biomedical Engineering; D006358:Hot Temperature; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D015233:Models, Statistical; D010100:Oxygen / Q000378:metabolism; D011140:Polyurethanes / Q000737:chemistry*; D011475:Prosthesis Failure; D012542:Scattering, Radiation; D012997:Solvents; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D014965:X-Rays
chemical_list: D001672:Biocompatible Materials; D011140:Polyurethanes; D012997:Solvents; C059617:pellethane 2363-55D; D000096:Acetone; D010100:Oxygen