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Rheology and Insulation Behaviour of Composites
Published in G. Mohamed Zakriya, G. Ramakrishnan, Natural Fibre Composites, 2020
G. Mohamed Zakriya, G. Ramakrishnan
Peeling, potential chalking, and cracking that eventually leads to loss of resin on the composite surface is called fibre blooming. The rate of UV degradation depends on geographical location, fibre loading, resin type, and filler packages. An acrylic, epoxy, or urethanes binder coating on the composite surface provides a moderate temperature resistance along with good strength, a high temperature resistance along with higher strength and good toughness obtained through respective binder formulations. A surface coating of 10–20 mm depth protects the composite material from UV degradation. Properly prepared Fibre reinforced polymer (FRP) composites accept a wide variety of surface painting like oil and water-based paints derived from acrylic and urethanes. Paints need not be breathable and no extraordinary surface preparation is mandatory. Proper abrasion and removal of residuals from mould-release agents helps to create an even surface finish for adhesive or mechanical attachment.32
Reduction method of stress concentration in GFRP repairing
Published in Airong Chen, Xin Ruan, Dan M. Frangopol, Life-Cycle Civil Engineering: Innovation, Theory and Practice, 2021
A. Sato, G. Hayashi, Y. Kitane, K. Sugiura
Many GFRP bridges have been constructed though the maintenance method has not been established yet. GFRP structures are said to be high durability because of its corrosion resistance, but UV degradation, delamination and fiber rupture may occur in these structures. UV degradation is the phenomenon which deteriorates the resin such as epoxy or unsaturated polyester in FRP. External damage can damage FRP and cause delamination or break the fiber embedded in it.
Turfgrass Insects
Published in L.B. (Bert) McCarty, Golf Turf Management, 2018
Ultraviolet light (UV) degradation. Exposure to sunlight often breaks chemical bonds that may make the compound inactive. Pyrethroids, insect growth regulators, bio (microbial) pesticides, and botanical insecticides are often susceptible to UV degradation. Applying susceptible products late in the evening and/or watering them off the leaf surface are two means turf managers can use to reduce UV degradation.
Performance indicators and specifications for fusion-bonded-epoxy(FBE)-coated steel rebars in concrete exposed to chlorides
Published in Sustainable and Resilient Infrastructure, 2023
Deepak K. Kamde, Marc Zintel, Sylvia Kessler, Radhakrishna G. Pillai
Similarly, corrosion resistance of coated steel can be enhanced by increasing the cross-linking and adhesion forces (Liu et al., 2013). It was reported that the dielectric and interface properties of the coated steel rebars can be enhanced by the use of barium titanate (Cheng et al., 2007). Monetta et al. (1993) reported that the addition of about 8.5% of polyamide to epoxy could increase the density and resistance of epoxy coating from 106 to 1011 Ωcm2. Similarly, Mayne (1973) reported that the use of about 10 moles per liter of CaCl2 can increase the electrical resistance of the coating. The use of additives can also improve the resistance to UV degradation. For example, the use of about 2% of carbon black nanoparticles could improve the UV resistance by two times (Ghasemi-Kahrizsangi et al., 2015). The use of photostabilizers such as TiO2 and ZnO are widely used additives to enhance the resistance to UV degradation (Nikafshar et al., 2017). Also, uniform distribution of such photostabilizers in the coating material is important for achieving effective and uniform UV resistance. Typically, such chemical compositions are also used for manufacturing FBE coating.
Exploration of polyvinylidene difluoride (PVDF) for improvement of weathering resistance of textile substrates
Published in The Journal of The Textile Institute, 2022
Bharathi Dasaradhan, Biswa Ranjan Das, Thako Hari Goswami, Namburi Eswara Prasad
Textile fabrics exposed to out-door environmental conditions are often subjected to various means of degradation. The different sources of degradation include UV rays, moisture and heat of the exposed environment. These factors greatly affect the different physical, mechanical and functional aspects of the textile fabrics and reduce their self-life and make them unfit for use over time. The different high strength fibres that dominate the world of technical textile industry are Nylon, Polyester, Kevlar and Spectra/Dyneema, etc. These fibres are highly sensitive to UV degradation and suffer from significant strength loss on direct exposure to sunlight. There are many studies that report the photo-degradation of these materials under natural/simulated out-door environmental conditions. Houshyar et al. (2018) investigated the degradation effect on different aramid fabrics after being irradiated by UV light and their results indicated a significant drop in the residual strength of around 50–80%, after exposure. Similarly, the degradation of other commercial textile fibres like Polyester and Nylon under UV exposure was also been studied and reported by other researchers (Dierickx & Berghe, 2004; Li et al., 2019; Moezzi & Ghane, 2013). Hence, there is need to protect the textile materials from UV degradation by application of UV stabilizers like TiO2, ZnO and FeO (Aloui et al., 2007; Berdahl et al., 2008; Fufa et al., 2013; Vlad-Cristea et al., 2010). These particles can be incorporated over fibre surface; (a) doping during melt spinning (Erdem et al., 2010; Nazari et al., 2013); (b) surface deposition by padding or sol-gel method or in-situ synthesis (Kathirvelu et al., 2009; Mihailovic et al., 2010; Sun et al., 2020; Xing & Ding, 2006); and (c) composite coating of suitable polymer incorporated with UV stabilizers (Forsthuber et al., 2013; Vlad-Cristea et al., 2012).