Papers by Keyword: Polymer Coating

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Authors: Oliver Weichold
Abstract: Glass rovings undergo a loss in tensile strength when aged in highly alkaline concrete. Based on the hypothesis that this loss is due to hydrolysis of the silicate network, binary polymer/pozzolan and ternary polymer/pozzolan/cement coating formulations have been developed in order to provide both corrosion protection and improved fibre-matrix adhesion. While the ternary mixtures were found to do either or, the best overall result was obtained with the binary mixture poly(vinyl acetate)/silica 20:80, showing a 1.8-fold increase in the pull-out load and a 1.6-fold increase in the residual tensile strength when compared to the as-received glass.
Authors: F. Mansfeld, L.T. Han, C.C. Lee, G. Zhang
Authors: Michal Kotoul, Petr Skalka, Ivo Dlouhy
Abstract: The paper deals with crack bridging modelling in Bioglass® based scaffolds due the presence of a special polymer coating. This includes a careful identification of bridging mechanism by polymer ligaments, selection of a suitable bridging model and its implementation into the gradient elasticity model of crack.
Authors: Yan Hong Tian, Zhan Qing Liu, Su Mei Kang, Xue Jun Zhang
Abstract: With toluene 2, 4-diisocyanate (TDI), polyethylene glycol (PEG) and 2,3-Epoxy-1-prop -anol (glycidol) used as the raw materials, two epoxy terminated polyurethanes (EPU) was synthesized by prepolymerization and closed end. Moreover, EPU with high toughhess is chosen as a coating agent for carbon fiber with three ethylene tetramine (TETA) as curing agen. The influence of the content of crosslinking agent in the coating layer on properties of composites and the mechanism of interface toughness are investigated. The chemical structure and thermal property of the EPU were studied with FTIR, 1HNMR and TGA, respectively. It proves that the thermal stability of EPU is more stable than epoxy coating. The interlaminar shear strength (ILSS) of the sized high modulus carbon fiber/epoxy composites is improved to 71MPa, which increased by 19.4% compared with the composites reinforced by unsized high modulus carbon fiber, and DMTA show that using EPU as a new kind of polymer coating for carbon fiber is a feasible method to improve the interfacial performance of high modulus carbon fiber/epoxy composites.
Authors: Liang Shi, Jian Zhong Liu, Jia Ping Liu
Abstract: The influence of polymer coating on the shrinkage of cement-based materials is comparatively analyzed in this paper. First of all, the relationship between cement-based materials shrinkage and water loss is discussed. Furthermore, some surface topography differences and pore structure changes of cement-based materials causing by polymer coating are investigated. At last, the affecting mechanism of polymer coating on reducing cement-based materials shrinkage is investigated. The results show that polymer coating can significantly reduce the shrinkage of cement-based materials. A more thick coating gets a higher shrinkage reducing ratio. There is a close relationship between cement-based materials water loss ratio and shrinkage ratio. Polymer coating can make the micro-crack on cement-based materials surface disappear. The cement-based materials coated with polymer have a lower surface layer cumulative average porosity than blank control group. The evaporation of capillary water and the development of negative capillary pressure in cement-based materials are controlled by polymer coating, thus the shrinkage becomes small.
Authors: Oliver Weichold, Markus Hojczyk, Alina Adams, Alexandra Olaru, Helge Stanjek
Abstract: Cement-in-polymer (c/p) dispersions allow the full utilisation of the reinforcing abilities of multifilament rovings in concrete. In this work the role of the polymer properties on the performance of the c/p dispersions is investigated and discussed. Two model polymers are chosen and c/p dispersions made with these are investigated regarding the water ingress velocity (NMR), the phase development during cement hydration (XRD), and the microstructure after cement hydration (SEM). Best mechanical performance is achieved with the hydrophobic poly(vinyl acetate) which regulates the water ingress and causes a slow hydration of the cement.
Authors: Cristian Pirvu, Mihaela Mindroiu, Ioana Demetrescu
Abstract: In this paper the elaboration and characterization of polypyrrole coatings on active metallic surfaces were performed. The one-step electropolymerization of pyrrole on zinc-coated steel electrodes was investigated under several techniques (cyclic voltammetry, electrochemical impedance spectroscopy, atomic force microscopy) in aqueous medium. Adherent and homogeneous PPy coatings were obtained using tartrate counter-ions. The obtained results show that the PPy coatings increase the corrosion potential and reduce the corrosion current.
Authors: Dariusz Szmigiel, Krzysztof Domański, Piotr Grabiec
Abstract: We investigated the plasma etching of polysiloxane intended for use in cochlear implants as a protection layer. The processing was performed using fluorine-based chemistry ionized in RIE (Reactive Ion Etching) or ICP (Inductively Coupled Plasma) discharge. The effect of temperature on polysiloxane etch rate and the resulting surface morphology was examined. XPS was employed to determine chemical changes induced by plasma treatment. The cytotoxicity on a cell line was observed in order to estimate suitability of plasma processed silicone elastomer for use in biomedical applications. This paper presents the selected results, which reveals how the polysiloxane surface properties can change depending upon plasma treatment conditions. Exemplary micro devices encapsulated in plasma treated silicone elastomer are also shown.
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