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Title: Novel polyurethane/graphene nanocomposite coatings
Author: Tong, Yao
ISNI:       0000 0004 7971 0645
Awarding Body: Loughborough University
Current Institution: Loughborough University
Date of Award: 2016
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A series of graphene based conductive and anticorrosion coatings were developed in this project. Multi-layer coating consists of EPD pristine graphene coating, PU/graphene primer and PU/graphene topcoat was developed. A simple mechanical-chemical approach was suggested to fabricate graphene with low cost and high efficiency. XRD was used to characterize the exfoliation efficiency of graphite. TEM was used to examine the size of the graphene sheets. SEM was used to characterize the surface morphology of the coatings. The particle size of all the carbon materials used was characterised by Malvern particle sizer. FTIR and XPS were used to characterize the chemical composition of the graphene powder and the coatings fabricated. MDSC and FTIR were used to monitor the cure dynamic of PU.The proposed mechanical-chemical approach was cost effective and suitable for large-scale production of graphene. XRD results indicated that the graphite layers were exfoliated efficiently and TEM results confirmed the existence of graphene. EPD was used to deposit graphene and PP10 graphite on steel substrates. With fine control of the EPD conditions and thermal treatment, electrical conductive coatings on steel substrates were produced successfully. The best electrical conductivity was 10 times higher than the electrical conductivity than steel substrate. The anticorrosion properties of the EPD coatings were not good due to their porous nature. Therefore, a polymeric protective coating is needed toimprove the anti-corrosion properties. Hybrid filler was adopted in the PU nanocomposites and the performance of the nanocomposites reinforced by hybrid filler was the best. The conductive mechanism of the nanocomposites was proposed. From the results of FTIR and MDSC, graphene had catalytic effect and steric hindrance effect on the cure of PU where catalytic effect was more obvious at high cure temperature and steric hindrance effect was more dominated with high graphene loading. GO also showed catalytic effect and steric hindrance effect. In addition, the functional groups on the GO surface can participate in the reaction with PU. Therefore, the reaction mechanism was altered. From the results, the addition of excessive amount of filler can significantly affect the cure behaviour of two-part PU and even reduce the crosslink density and weaken its mechanical properties.
Supervisor: Not available Sponsor: Tata Steel Europe
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Materials Engineering not elsewhere classified ; Graphene ; Polymer nanocomposite ; Coating ; Electrical conductivity ; Anti-corrosion