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Degradation studies on segmented polyurethanes prepared with HMDI, PCL and different chain extenders

Paper ID Volume ID Publish Year Pages File Format Full-Text
1405 83 2010 10 PDF Available
Title
Degradation studies on segmented polyurethanes prepared with HMDI, PCL and different chain extenders
Abstract

Biodegradable segmented polyurethanes (BSPUs) were prepared with poly(caprolactone) as a soft segment, 4,4′-methylene bis (cyclohexyl isocyanate) and either butanediol (BSPU1) or dithioerythritol (BSPU2) as a chain extender. BSPU samples were characterized in terms of their physicochemical properties and their hemocompatibility. Polymers were then degraded in acidic (HCl 2 N), alkaline (NaOH 5 M) and oxidative (H2O2 30 wt.%) media and characterized by their mass loss, Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Undegraded BSPU1 and BSPU2 exhibited different properties, such as the glass transition temperature Tg of the soft segment (−25 vs. 4 °C), mechanical properties (600% vs. 900% strain to break) and blood coagulating properties (clotting time = 11.46 vs. 8.13 min). After acidic and alkaline degradation, the disappearance of the 1728 cm−1 band of polycaprolactone (PCL) on both types of BSPU was detected by FTIR. However, the oxidative environment did not affect the soft segment severely as the presence of PCL crystalline domains were observed both by DSC (melting temperature Tm = 52.8 °C) and XRD (2θ = 21.3° and 23.7°). By TGA three decomposition temperatures were recorded for both BSPU samples, but the higher decomposition temperature was enhanced after acidic and alkaline degradation. The formation of the porous structure on BSPU1 was observed by SEM, while a granular surface was observed on BSPU2 after alkaline degradation.

Keywords
Polycaprolactone; Segmented polyurethanes; Cardiovascular; Chemical degradation; Thiol chain extender
First Page Preview
Degradation studies on segmented polyurethanes prepared with HMDI, PCL and different chain extenders
Publisher
Database: Elsevier - ScienceDirect
Journal: Acta Biomaterialia - Volume 6, Issue 6, June 2010, Pages 2035–2044
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering