Investigating the Effects of Nitric Acid Treatments on the Properties of Recycled Carbon Fiber

In this study, the chemical state change of recycled carbon fiber (rCF) surfaces and the mechanism of the oxygen functional groups according to nitric acid treatment at various times and temperatures were investigated to upcycle the carbon fiber recovered from used carbon composite. When treated wit...

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Main Authors: Gyungha Kim, Hyunkyung Lee, Minsu Kim, Dae Up Kim
Format: Article
Language:English
Published: MDPI AG 2023-02-01
Series:Polymers
Subjects:
Online Access:https://www.mdpi.com/2073-4360/15/4/824
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author Gyungha Kim
Hyunkyung Lee
Minsu Kim
Dae Up Kim
author_facet Gyungha Kim
Hyunkyung Lee
Minsu Kim
Dae Up Kim
author_sort Gyungha Kim
collection DOAJ
description In this study, the chemical state change of recycled carbon fiber (rCF) surfaces and the mechanism of the oxygen functional groups according to nitric acid treatment at various times and temperatures were investigated to upcycle the carbon fiber recovered from used carbon composite. When treated with nitric acid at 25 °C, the carbon fiber surface demonstrated the same tensile properties as untreated carbon fiber (CF) for up to 5 h, and the oxygen functional group and polar surface energy of C–O (hydroxyl group) and C=O (carbonyl group) increased slightly compared to the untreated CF up to 5 h. On the other hand, at 100 °C, the tensile properties slightly decreased compared to untreated CF up to 5 h, and the amount of C–O and C=O decreased and the amount of O=C–O (lactone group) started to increase until 1 h. After 1 h, the amount of C-O and C=O decreased significantly, and the amount of O=C–O increased rapidly. At 5 h, the amount of oxygen functional groups increased by 92%, and the polar surface energy increased by 200% compared to desized CF. It was determined that the interfacial bonding force increased the most because the oxygen functional group, O=C–O, increased greatly at 100 °C and 5 h.
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spelling doaj.art-217f3aaaf8a64dafacd62ab13e9c28732023-11-16T22:50:26ZengMDPI AGPolymers2073-43602023-02-0115482410.3390/polym15040824Investigating the Effects of Nitric Acid Treatments on the Properties of Recycled Carbon FiberGyungha Kim0Hyunkyung Lee1Minsu Kim2Dae Up Kim3Carbon & Light Materials Application Group, Korea Institute of Industrial Technology, 222 Palbok-ro, Deokjin-gu, Jeonju 54853, Republic of KoreaCarbon & Light Materials Application Group, Korea Institute of Industrial Technology, 222 Palbok-ro, Deokjin-gu, Jeonju 54853, Republic of KoreaCarbon & Light Materials Application Group, Korea Institute of Industrial Technology, 222 Palbok-ro, Deokjin-gu, Jeonju 54853, Republic of KoreaCarbon & Light Materials Application Group, Korea Institute of Industrial Technology, 222 Palbok-ro, Deokjin-gu, Jeonju 54853, Republic of KoreaIn this study, the chemical state change of recycled carbon fiber (rCF) surfaces and the mechanism of the oxygen functional groups according to nitric acid treatment at various times and temperatures were investigated to upcycle the carbon fiber recovered from used carbon composite. When treated with nitric acid at 25 °C, the carbon fiber surface demonstrated the same tensile properties as untreated carbon fiber (CF) for up to 5 h, and the oxygen functional group and polar surface energy of C–O (hydroxyl group) and C=O (carbonyl group) increased slightly compared to the untreated CF up to 5 h. On the other hand, at 100 °C, the tensile properties slightly decreased compared to untreated CF up to 5 h, and the amount of C–O and C=O decreased and the amount of O=C–O (lactone group) started to increase until 1 h. After 1 h, the amount of C-O and C=O decreased significantly, and the amount of O=C–O increased rapidly. At 5 h, the amount of oxygen functional groups increased by 92%, and the polar surface energy increased by 200% compared to desized CF. It was determined that the interfacial bonding force increased the most because the oxygen functional group, O=C–O, increased greatly at 100 °C and 5 h.https://www.mdpi.com/2073-4360/15/4/824recycled carbon fibernitric acidfunctional groupsurface free energymechanism
spellingShingle Gyungha Kim
Hyunkyung Lee
Minsu Kim
Dae Up Kim
Investigating the Effects of Nitric Acid Treatments on the Properties of Recycled Carbon Fiber
Polymers
recycled carbon fiber
nitric acid
functional group
surface free energy
mechanism
title Investigating the Effects of Nitric Acid Treatments on the Properties of Recycled Carbon Fiber
title_full Investigating the Effects of Nitric Acid Treatments on the Properties of Recycled Carbon Fiber
title_fullStr Investigating the Effects of Nitric Acid Treatments on the Properties of Recycled Carbon Fiber
title_full_unstemmed Investigating the Effects of Nitric Acid Treatments on the Properties of Recycled Carbon Fiber
title_short Investigating the Effects of Nitric Acid Treatments on the Properties of Recycled Carbon Fiber
title_sort investigating the effects of nitric acid treatments on the properties of recycled carbon fiber
topic recycled carbon fiber
nitric acid
functional group
surface free energy
mechanism
url https://www.mdpi.com/2073-4360/15/4/824
work_keys_str_mv AT gyunghakim investigatingtheeffectsofnitricacidtreatmentsonthepropertiesofrecycledcarbonfiber
AT hyunkyunglee investigatingtheeffectsofnitricacidtreatmentsonthepropertiesofrecycledcarbonfiber
AT minsukim investigatingtheeffectsofnitricacidtreatmentsonthepropertiesofrecycledcarbonfiber
AT daeupkim investigatingtheeffectsofnitricacidtreatmentsonthepropertiesofrecycledcarbonfiber