Kim Gyungha, Lee Hyunkyung, Kim Kyungeun, Kim Dae Up
Carbon & Light Materials Application Group, Korea Institute of Industrial Technology, 222, Palbok-ro, Deokjin-gu, Jeonju-city 54853, Jeollabuk-do, Korea.
Polymers (Basel). 2022 Jun 14;14(12):2412. doi: 10.3390/polym14122412.
In this study, carbon fibers were heat-treated in a nitrogen and oxygen atmosphere according to temperature to elucidate the mechanism of chemical state changes and oxygen functional group changes on the carbon fiber surface by analyzing the mechanical and chemical properties of carbon fibers. Carbon fibers before and after heat treatment were analyzed using FE-SEM (Field Emission Scanning), UTM (Universal Tensile Testers), XPS (X-ray Photoelectron Spectroscopy), and surface-free energy. In the nitrogen atmosphere, which is an inert gas, the tensile strength was equivalent to that of the virgin up to 500 °C but decreased to 71% with respect to the virgin at 1000 °C. Furthermore, as the temperature increased from room temperature to 1000 °C, the oxygen functional group and the polar free energy gradually decreased compared with the virgin. On the other hand, in the oxygen atmosphere, which is an active gas, the tensile properties were not significantly different from those of the virgin up to 300 °C but gradually decreased at 500 °C. Above 600 °C, the carbon fibers deteriorated, and measurement was impossible. The oxygen functional group decreased at 300 °C, but above 300 °C, among the oxygen functional groups, the hydroxyl group and the carbonyl group increased. Furthermore, the lactone group formed and rapidly increased compared with the virgin, and the polar free energy increased as the temperature increased.
在本研究中，根据温度在氮气和氧气气氛中对碳纤维进行热处理，通过分析碳纤维的力学和化学性能，以阐明碳纤维表面化学状态变化和氧官能团变化的机制。使用场发射扫描电子显微镜（FE-SEM）、万能拉伸试验机（UTM）、X射线光电子能谱仪（XPS）和表面自由能对热处理前后的碳纤维进行分析。在作为惰性气体的氮气气氛中，直至500℃时的拉伸强度与原始碳纤维相当，但在1000℃时相对于原始碳纤维下降至71%。此外，随着温度从室温升高至1000℃，与原始碳纤维相比，氧官能团和极性自由能逐渐降低。另一方面，在作为活性气体的氧气气氛中，直至300℃时拉伸性能与原始碳纤维无显著差异，但在500℃时逐渐下降。600℃以上，碳纤维发生劣化，无法进行测量。氧官能团在300℃时减少，但在300℃以上，在氧官能团中，羟基和羰基增加。此外，内酯基形成并与原始碳纤维相比迅速增加，并且极性自由能随温度升高而增加。
