Dithiothreitol-based polyurethanes. Synthesis and degradation studies

作者：Ferris Cristina; Violante de Paz M; Zamora Francisca; Galbis Juan A^*

来源：Polymer Degradation and Stability, 2010, 95(9): 1480-1487.

DOI：10.1016/j.polymdegradstab.2010.06.021

• Polyurethane synthesis
• DSC and TGA studies
• Biodegradable polyurethanes
• Lipase-catalyzed degradation
• alpha-chymotrypsin-catalyzed degradation

The synthesis, characterization, and some properties of new copolyurethanes are described. These copolyurethanes were obtained by reaction of 1,4-di-S-benzyl-D,L-dithiothreitol (DTTSBn) and triethylene glycol (TEG) with 1,6-hexamethylene diisocyanate (HMDI). The copolymer compositions were studied by H-1 NMR, revealing that the content of the copolymer units is in good agreement with that of their corresponding feed. The PU(TEG-HMDI) homopolymer exhibited a high crystallinity, but the introduction of the DTTSBn diol led to a reduction in the crystallinity of the copolymers and an increase of the stiffness, with associated increases in the T-g values. In their TG curves, the copolymers exhibited a mixed trend of the related homopolymers; all of them were thermally stable, with degradation temperatures above 250 C and with higher thermal resistance displayed by the polymers with higher TEG contents. The chemical and enzymatically catalyzed hydrolytic degradations of the macromolecules were tested. PU(TEG-HMDI) was the only polymer degraded under physiological conditions, but an increase of temperature markedly affected the degradation rates. Two proteolytic enzymes (papain and alpha-chymotrypsin) and two esterase enzymes (cholesterol esterase and lipase) were chosen to perform enzyme-mediated hydrolysis trials, the first reported use of pancreatic lipase for urethane-bond hydrolysis in polyurethanes.

• 出版日期2010-9