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Management of waste from carbon fibre composites has become a significant societal issue as the application of composite grows across many industries. In this study, carbon fibres (CF) were successfully recovered from cured carbon fibre/epoxy (CF/EP) prepreg under microwave pyrolysis at 450, 550 and 650 °C followed by oxidation of any residual char. The recovered fibres were investigated for their tensile properties, surface morphologies and the elements/functional groups presented on the surface. The chemical compositions of gaseous and oil pyrolysis products were also analysed. The microwave pyrolysis effectively pyrolyzed the epoxy (EP) resin. Char residue remained on the fibre surface and the amount of char reduced as the pyrolysis temperature increased. Compared to virgin fibres, the recovered fibre suffered from a strength reduction by less than 20%, and this reduction could be mitigated by reducing the pyrolysis temperature. The surface of recovered fibre remained clean and smooth, while the profile of elements and functional groups at the surface were similar to those of virgin fibres. The main gaseous products were CO, H2, CO2 and CH4, whilst the liquid product stream included phenolic and aromatic compounds.
Siqi Hao; Lizhe He; Jiaqi Liu; Yuhao Liu; Chris Rudd; Xiaoling Liu. Recovery of Carbon Fibre from Waste Prepreg via Microwave Pyrolysis. Polymers 2021, 13, 1231 .
AMA StyleSiqi Hao, Lizhe He, Jiaqi Liu, Yuhao Liu, Chris Rudd, Xiaoling Liu. Recovery of Carbon Fibre from Waste Prepreg via Microwave Pyrolysis. Polymers. 2021; 13 (8):1231.
Chicago/Turabian StyleSiqi Hao; Lizhe He; Jiaqi Liu; Yuhao Liu; Chris Rudd; Xiaoling Liu. 2021. "Recovery of Carbon Fibre from Waste Prepreg via Microwave Pyrolysis." Polymers 13, no. 8: 1231.
Hybrid composites composed of bio-based thin-ply carbon fibre prepreg and flame-retardant mats (E20MI) have been produced to investigate the effects of laminate design on their fire protection performance and mechanical properties. These flame-retardant mats rely primarily on expandable graphite, mineral wool and glass fibre to generate a thermal barrier that releases incombustible gasses and protects the underlying material. A flame retardant (FR) mat is incorporated into the carbon fibre bio-based polymeric laminate and the relationship between the fire protection properties and mechanical properties is investigated. Hybrid composite laminates containing FR mats either at the exterior surfaces or embedded 2-plies deep have been tested by the limited oxygen index (LOI), vertical burning test and cone calorimetry. The addition of the surface or embedded E20MI flame retardant mats resulted in an improvement from a base line of 33.1% to 47.5% and 45.8%, respectively. All laminates passed the vertical burning test standard of FAR 25.853. Cone calorimeter data revealed an increase in the time to ignition (TTI) for the hybrid composites containing the FR mat, while the peak of heat release rate (PHRR) and total heat release (TTR) were greatly reduced. Furthermore, the maximum average rate of heat emission (MARHE) values indicated that both composites with flame retardant mats had achieved the requirements of EN 45545-2. However, the tensile strengths of laminates with surface or embedded flame-retardant mats were reduced from 1215.94 MPa to 885.92 MPa and 975.48 MPa, respectively. Similarly, the bending strength was reduced from 836.41 MPa to 767.03 MPa and 811.36 MPa, respectively.
Xiaoye Cong; Pooria Khalili; Chenkai Zhu; Saihua Li; Jingjing Li; Chris Rudd; Xiaoling Liu. Investigation of Fire Protection Performance and Mechanical Properties of Thin-Ply Bio-Epoxy Composites. Polymers 2021, 13, 731 .
AMA StyleXiaoye Cong, Pooria Khalili, Chenkai Zhu, Saihua Li, Jingjing Li, Chris Rudd, Xiaoling Liu. Investigation of Fire Protection Performance and Mechanical Properties of Thin-Ply Bio-Epoxy Composites. Polymers. 2021; 13 (5):731.
Chicago/Turabian StyleXiaoye Cong; Pooria Khalili; Chenkai Zhu; Saihua Li; Jingjing Li; Chris Rudd; Xiaoling Liu. 2021. "Investigation of Fire Protection Performance and Mechanical Properties of Thin-Ply Bio-Epoxy Composites." Polymers 13, no. 5: 731.
Composites of biodegradable phosphate glass fiber and polylactic acid (PGF/PLA) show potential for bone tissue engineering scaffolds, due to their ability to release Ca, P, and Mg during degradation, thus promoting the bone repair. Nevertheless, glass degradation tends to acidify the surrounding aqueous environment, which may adversely affect the viability and bone-forming activities of osteoblasts. In this work, MgO was investigated as a neutralizing agent. Porous network-phase gyroid scaffolds were additive-manufactured using four different materials: PLA, MgO/PLA, PGF/PLA, and (MgO + PGF)/PLA. The addition of PGF enhanced compressive properties of scaffolds, and the resultant scaffolds were comparably strong and stiff with human trabecular bone. While the degradation of PGF/PLA composite induced considerable acidity in degradation media and intensified the degradation of PGF in return, the degradation media of (MgO + PGF)/PLA maintained a neutral pH close to a physiological environment. The experiment results indicated the possible mechanism of MgO as the neutralizing agent: the local acidity was buffered as the MgO reacted with the acidic degradation products thereby inhibiting the degradation of PGF from being intensified in an acidic environment. The (MgO + PGF)/PLA composite scaffold appears to be a candidate for bone tissue engineering.
Lizhe He; Xiaoling Liu; Chris Rudd. Additive-Manufactured Gyroid Scaffolds of Magnesium Oxide, Phosphate Glass Fiber and Polylactic Acid Composite for Bone Tissue Engineering. Polymers 2021, 13, 270 .
AMA StyleLizhe He, Xiaoling Liu, Chris Rudd. Additive-Manufactured Gyroid Scaffolds of Magnesium Oxide, Phosphate Glass Fiber and Polylactic Acid Composite for Bone Tissue Engineering. Polymers. 2021; 13 (2):270.
Chicago/Turabian StyleLizhe He; Xiaoling Liu; Chris Rudd. 2021. "Additive-Manufactured Gyroid Scaffolds of Magnesium Oxide, Phosphate Glass Fiber and Polylactic Acid Composite for Bone Tissue Engineering." Polymers 13, no. 2: 270.
In this concept-proof study, a preform-based RTM (Resin Transfer Molding) process is presented that is characterized by first pre-loading the solid curing agent onto the preform, and then injecting the liquid nonreactive resin with an intrinsically low viscosity into the mold to infiltrate and wet the pre-loaded preform. The separation of resin and hardener helped to process inherently high viscosity resins in a convenient way. Rosin-sourced, anhydrite-cured epoxies that would normally be regarded as unsuited to liquid composite molding, were thus processed. Rheological tests revealed that by separating the anhydrite curing agent from a formulated RTM resin system, the remaining epoxy liquid had its flowtime extended. C-scan and glass transition temperature tests showed that the preform pre-loaded with anhydrite was fully infiltrated and wetted by the liquid epoxy, and the two components were diffused and dissolved with each other, and finally, well reacted and cured. Composite laminates made via this approach exhibited roughly comparable quality and mechanical properties with prepreg controls via autoclave or compression molding, respectively. These findings were verified for both carbon and ramie fiber composites.
Sicong Yu; Xufeng Zhang; Xiaoling Liu; Chris Rudd; Xiaosu Yi. A Conceptional Approach of Resin-Transfer-Molding to Rosin-Sourced Epoxy Matrix Green Composites. Aerospace 2020, 8, 5 .
AMA StyleSicong Yu, Xufeng Zhang, Xiaoling Liu, Chris Rudd, Xiaosu Yi. A Conceptional Approach of Resin-Transfer-Molding to Rosin-Sourced Epoxy Matrix Green Composites. Aerospace. 2020; 8 (1):5.
Chicago/Turabian StyleSicong Yu; Xufeng Zhang; Xiaoling Liu; Chris Rudd; Xiaosu Yi. 2020. "A Conceptional Approach of Resin-Transfer-Molding to Rosin-Sourced Epoxy Matrix Green Composites." Aerospace 8, no. 1: 5.
A high temperature epoxy resin was formulated by using a rosin-sourced anhydride-type curing agent, i.e., maleopimaric acid (RAM), and a two-component epoxy consisting of an E51-type epoxy and a solid phenolic epoxy to form a bio-sourced green matrix resin. The glass transition temperature of the final resin was 238 °C Carbon fiber composite prepreg and was manufactured and laminated into composite specimens. Interleaving Toughening Technology (ITT) was applied to the laminates by using Polyamide interleaf veils. The interlaminar fracture toughness and compression after impact (CAI) strength were investigated and showed that the opening Mode I interlaminar fracture toughness GIC and the Mode II interlaminar fracture toughness GIIC of the specimens with interleaves were significantly improved from 227.51 J/m2 to 509.22 J/m2 and 1064.3 J/m2 to 1510.8 J/m2, respectively. Correspondingly, the drop-weight impact test shows that the interleaves reduced the impact damage area from 20.9% to 11.3% of the total area, and the CAI residual strength was increased from 144 MPa to 191 MPa. Meanwhile, mechanical tests showed that the in-plane properties of the interleaved laminates were slightly reduced due to carbon fiber volume fraction reduction. In conclusion, the high glass transition temperature, fracture toughness and CAI behaviour make the green resin matrix composite a potential candidate for aerospace applications.
Dongyuan Hu; Xvfeng Zhang; Xiaoling Liu; Zhen Qin; Li Hu; Chris Rudd; Xiaosu Yi. Study on Toughness Improvement of a Rosin-Sourced Epoxy Matrix Composite for Green Aerospace Application. Journal of Composites Science 2020, 4, 168 .
AMA StyleDongyuan Hu, Xvfeng Zhang, Xiaoling Liu, Zhen Qin, Li Hu, Chris Rudd, Xiaosu Yi. Study on Toughness Improvement of a Rosin-Sourced Epoxy Matrix Composite for Green Aerospace Application. Journal of Composites Science. 2020; 4 (4):168.
Chicago/Turabian StyleDongyuan Hu; Xvfeng Zhang; Xiaoling Liu; Zhen Qin; Li Hu; Chris Rudd; Xiaosu Yi. 2020. "Study on Toughness Improvement of a Rosin-Sourced Epoxy Matrix Composite for Green Aerospace Application." Journal of Composites Science 4, no. 4: 168.
Wind energy has been considered as one of the greenest renewable energy sources over the last two decades. However, attention is turning to reducing the possible environmental impacts from this sector. We argue that wind energy would not be effectively “green” if anthropogenic materials are not given attention in a responsible manner. Using the concept of the circular economy, this paper considers how anthropogenic materials in the form of carbon fibers can reenter the circular economy system at the highest possible quality. This paper first investigates the viability of a carbon-fiber-reinforced polymer extraction process using thermal pyrolysis to recalibrate the maximum carbon fiber value by examining the effect of (a) heating rate, (b) temperature, and (c) inert gas flow rate on char yield. With cleaner and higher quality recovered carbon fibers, this paper discusses the economic preconditions for the takeoff and growth of the industry and recommends the reuse of extracted carbon fibers to close the circular economy loop.
Siqi Hao; Adrian T.H. Kuah; Christopher D. Rudd; Kok Hoong Wong; Nai Yeen Gavin Lai; Jianan Mao; Xiaoling Liu. A circular economy approach to green energy: Wind turbine, waste, and material recovery. Science of The Total Environment 2019, 702, 135054 .
AMA StyleSiqi Hao, Adrian T.H. Kuah, Christopher D. Rudd, Kok Hoong Wong, Nai Yeen Gavin Lai, Jianan Mao, Xiaoling Liu. A circular economy approach to green energy: Wind turbine, waste, and material recovery. Science of The Total Environment. 2019; 702 ():135054.
Chicago/Turabian StyleSiqi Hao; Adrian T.H. Kuah; Christopher D. Rudd; Kok Hoong Wong; Nai Yeen Gavin Lai; Jianan Mao; Xiaoling Liu. 2019. "A circular economy approach to green energy: Wind turbine, waste, and material recovery." Science of The Total Environment 702, no. : 135054.