El-Taweel Safaa H, Medany Shymaa S, Alhaddad Omaima, Hefnawy Mahmoud A
Department of Chemistry, Faculty of Science, Cairo University, Orman-Giza 12613, Egypt.
Engineering and Materials Science Department, German University in Cairo, New Cairo City, 11835, Cairo, Egypt.
ACS Omega. 2025 Aug 5;10(32):35551-35565. doi: 10.1021/acsomega.5c00139. eCollection 2025 Aug 19.
The influence of the graphene oxide (GO) in weight percentage from 0.05 to 0.6 wt % on the PLA's physical properties was investigated using X-ray Diffraction (XRD), DSC, thermogravimetric analysis, polarized optical microscopy, and impedance measurements. The experimental results indicate that incorporating GO into Polylactic acid (PLA) improves its thermal properties by quickly reaching the optimum percentage of crystallinity (from ∼8.5 to 55%), slightly increasing the maximum thermal degradation temperature (from 340 to 347 °C), and drastically reducing the size of PLA's spherulites. Additionally, the electrical impedance values decreased by 64% as the percentage of GO increased from 0.05 to 0.6 wt %. Furthermore, the PLA composite was soaked in a 10 wt % NaCl solution for different time intervals of up to 21 days. The electrochemical behavior of the PLA-GO composite was investigated by using electrochemical impedance spectroscopy. The electrical conductivity change was performed as a function of the charge-transfer resistance. For the PLA-GO-0.6 sample, the charge-transfer resistance increased by approximately 26% after 21 days of immersion in NaCl solution, attributed to the swelling of graphene oxide (GO). Optical microscopy revealed notable changes in surface morphology during soaking in 10 wt % NaCl, with the formation of irregular channels resulting from the expansion of GO within the PLA matrix.
研究了氧化石墨烯（GO）的重量百分比从0.05%到0.6%对聚乳酸（PLA）物理性能的影响，采用了X射线衍射（XRD）、差示扫描量热法（DSC）、热重分析、偏光显微镜和阻抗测量等方法。实验结果表明，将GO掺入聚乳酸（PLA）中可改善其热性能，能快速达到最佳结晶度百分比（从约8.5%提高到55%），略微提高最大热降解温度（从340℃提高到347℃），并大幅减小PLA球晶的尺寸。此外，随着GO的百分比从0.05%增加到0.6%，电阻抗值降低了64%。此外，将PLA复合材料浸泡在10 wt%的NaCl溶液中长达21天的不同时间间隔。通过电化学阻抗谱研究了PLA-GO复合材料的电化学行为。电导率变化是作为电荷转移电阻的函数进行的。对于PLA-GO-0.6样品，在NaCl溶液中浸泡21天后电荷转移电阻增加了约26%，这归因于氧化石墨烯（GO）的膨胀。光学显微镜显示，在浸泡于10 wt%的NaCl溶液过程中，表面形态发生了显著变化，由于GO在PLA基质中膨胀而形成了不规则通道。
