Tan Hwee Yun, Widjaja Effendi, Boey Freddy, Loo Say Chye Joachim
School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.
J Biomed Mater Res B Appl Biomater. 2009 Oct;91(1):433-40. doi: 10.1002/jbm.b.31419.
The in vitro hydrolytic degradation of irradiated biodegradable polymers was studied. Poly(L-lactide), poly(lactide-co-glycolic acid) (PLGA)(80:20), and PLGA(50:50) polymers were first electron beam irradiated at 5 Mrad before hydrolytic degradation. Hydrolysis of these films was characterized through their physical properties--mass loss, average molecular weight, and thermal properties. Changes to the chemical structures of these polyesters were also analyzed using Fourier-transformed infrared (FTIR) and Raman spectroscopy, and the spectra results were correlated to their physical properties. The results showed that an increase in hydroxyl (OH) group, observed from the FTIR spectroscopy, indicates that the polymer is degrading through hydrolysis--first-stage degradation. Subsequently, a decrease in C==O group, observed from Raman spectroscopy, indicates that the polymer is experiencing mass loss--second-stage degradation. Therefore, a good correlation exists in determining the extent of polymer degradation through the use of FTIR and Raman spectroscopy by observing changes to the OH and C==O groups from the spectra of these nondestructive techniques.
研究了辐照可生物降解聚合物的体外水解降解。聚（L-丙交酯）、聚（丙交酯-共-乙醇酸）（PLGA）（80:20）和PLGA（50:50）聚合物在进行水解降解之前，首先用5兆拉德的电子束进行辐照。通过这些薄膜的物理性质——质量损失、平均分子量和热性质来表征其水解情况。还使用傅里叶变换红外（FTIR）和拉曼光谱分析了这些聚酯化学结构的变化，并将光谱结果与其物理性质相关联。结果表明，从FTIR光谱观察到的羟基（OH）基团增加，表明聚合物正在通过水解进行降解——第一阶段降解。随后，从拉曼光谱观察到的C==O基团减少，表明聚合物正在经历质量损失——第二阶段降解。因此，通过观察这些无损技术光谱中OH和C==O基团的变化，利用FTIR和拉曼光谱来确定聚合物降解程度存在良好的相关性。
