Please use this identifier to cite or link to this item:
|Title:||Biodegradable thermogelling poly(ester urethane)s consisting of poly(lactic acid) - Thermodynamics of micellization and hydrolytic degradation|
|Source:||Loh, X.J., Tan, Y.X., Li, Z., Teo, L.S., Goh, S.H., Li, J. (2008-05). Biodegradable thermogelling poly(ester urethane)s consisting of poly(lactic acid) - Thermodynamics of micellization and hydrolytic degradation. Biomaterials 29 (14) : 2164-2172. ScholarBank@NUS Repository. https://doi.org/10.1016/j.biomaterials.2008.01.016|
|Abstract:||Multiblock poly(ether ester urethane)s comprising of poly(lactic acid) (PLA), poly(ethylene glycol) (PEG), and poly(propylene glycol) (PPG) segments were synthesized, and their aqueous solutions exhibited thermogelling behavior at critical gelation concentrations (CGC) ranging from 7 to 9 wt%. The chemical structures and molecular characteristics of the copolymers were studied by GPC, 1H NMR, 13C NMR and FTIR. The thermal stability of the poly(PEG/PPG/PLA urethane)s was studied by thermogravimetry analysis (TGA), and the PLA contents were calculated based on the thermal degradation profile. The results were in good agreement with those obtained from the 1H NMR measurements. The critical micellization concentration (CMC) of these water-soluble poly(ether ester urethane)s was determined at different temperatures using a dye solubilization method. The thermodynamic parameters for micelle formation were calculated, indicating that the process is largely entropy-driven. Interestingly, it appears that there exists a requirement for the system to possess a minimum gain in entropy before the thermogelling effect can be observed. Dilute copolymer solutions showed a lower critical solution temperature (LCST) behavior similar to pNIPAM dissolved in aqueous solutions. The thermogels hydrolytically degraded to polymer fragments corresponding to the constituent segment blocks within 3 months. © 2008 Elsevier Ltd. All rights reserved.|
|Appears in Collections:||Staff Publications|
Show full item record
Files in This Item:
There are no files associated with this item.
checked on Feb 21, 2018
WEB OF SCIENCETM
checked on Jan 15, 2018
checked on Feb 18, 2018
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.