کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10368 682 2008 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Biodegradable thermogelling poly(ester urethane)s consisting of poly(lactic acid) – Thermodynamics of micellization and hydrolytic degradation
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی بیو مهندسی (مهندسی زیستی)
پیش نمایش صفحه اول مقاله
Biodegradable thermogelling poly(ester urethane)s consisting of poly(lactic acid) – Thermodynamics of micellization and hydrolytic degradation
چکیده انگلیسی

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.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biomaterials - Volume 29, Issue 14, May 2008, Pages 2164–2172
نویسندگان
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