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Pure Epoxy (pure + epoxy)
Selected AbstractsEpoxy composites reinforced by different size silica nanoparticlesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Cheng-Fang Ou Abstract Three series of epoxy/SiO2 composites, containing 0.3,7 wt % nanosized SiO2 with different specific surface area, were prepared by solution blending. The resulting composites exhibit the higher glass transition temperature (Tg) than that of pure epoxy. The Tg of composite showed a maximum increment of 35.3°C by the addition of 7 wt % A300. The trade name of A300 is Aerosil 300. It is one of the fumed silica nanoparticles products of Degussa. The decomposition temperatures (Td) of composites were always higher than that of pure epoxy and showed a maximum increment of 20.8°C by the addition of 5 wt % A300. The light transmittance of composites was as a function of the SiO2 content and size. The water permeability of composites decreased with increasing SiO2 content and the 7 wt % A300 composite exhibits a maximum decrement percentage of 35.6%. The Tg, Td, storage modulus, and water-vapor barrier property are as a function of the SiO2 content and size. These properties increased as the content of SiO2 increased. The finer SiO2 are more effective in increasing the Tg, Td, and water-vapor barrier property. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Influence of fiber orientation on high stress wear behavior of sisal fiber-reinforced epoxy compositesPOLYMER COMPOSITES, Issue 4 2007Navin Chand Sisal fiber-reinforced epoxy composites having three different fiber orientations, namely LL, LT, TT mentioned in the text were prepared and tested for their high stress abrasive wear behavior. Effect of fiber orientation, sliding distance, and load on abrasive wear of sisal,epoxy composites have been determined. Wear data of composites have been compared with the pure epoxy. Incorporation of fibers decreases the wear rate of epoxy resin, which varies with the fiber orientation. Wear rate in case of TT composite is found minimum as compared to other two composites. Wear rate follows the following trend, WTT < WLT < WLL. Owing to minimum exposed area of fiber to the sliding asperities, lowest wear rate occurs in the case of TT composite. Increase of load and sliding distance increases the wear volume in all the composites, because of the progressive loss of material. Wear mechanism has been discussed by using SEM micrographs of the worn surfaces. POLYM. COMPOS., 28:437,441, 2007. © 2007 Society of Plastics Engineers. [source] Effects of rubber-rich domains and the rubber-plasticized matrix on the fracture behavior of liquid rubber-modified araldite-F epoxiesPOLYMER ENGINEERING & SCIENCE, Issue 11 2000Keqin Xiao The fracture behavior of a bisphenol A diglycidylether (DGEBA) epoxy, Araldite F, modified using carboxyl-terminated copolymer of butadiene and acrylonitrile (CTBN) rubber up to 30 wt%, is studied at various crosshead rates. Fracture toughness, KIC, measured using compact tension (CT) specimens, is significantly improved by adding rubber to the pure epoxy. Dynamic mechanical analysis (DMA) was applied to analyze dissolution behavior of the epoxy resin and rubber, and their effects on the fracture toughness and toughening mechanisms of the modified epoxies were investigated. Scanning electron microscopy (SEM) observation and DMA results show that epoxy resides in rubber-rich domains and the structure of the rubber-rich domains changes with variation of the rubber content. Existence of an optimum rubber content for toughening the epoxy resin is ascribed to coherent contributions from the epoxy-residing dispersed rubber phase and the rubber-dissolved epoxy continuous phase. No rubber cavitation in the fracture process is found, the absence of which is explained as a result of dissolution of the epoxy resin into the rubber phase domains, which has a negative effect on the improvement of fracture toughness of the materials. Plastic deformation banding at the front of precrack tip, formed as a result of stable crack propagation, is identified as the major toughening process. [source] Layered silicate/epoxy nanocomposites: synthesis, characterization and propertiesPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 5 2004Nehal A. Salahuddin Abstract Novel epoxy-clay nanocomposites have been prepared by epoxy and organoclays. Polyoxypropylene triamine (Jeffamine T-403), primary polyethertriamine (Jeffamine T-5000) and three types of polyoxypropylene diamine (Jeffamine D-230, D-400, D-2000) with different molecular weight were used to treat Na-montmorillonite (MMT) to form organoclays. The preparation involves the ion exchange of Na+ in MMT with the organic ammonium group in Jeffamine compounds. X-ray diffraction (XRD) confirms the intercalation of these organic moieties to form Jeffamine-MMT intercalates. Jeffamine D-230 was used as a swelling agent for the organoclay and curing agent. It was established that the d001 spacing of MMT in epoxy-clay nanocomposites depends on the silicate modification. Although XRD data did not show any apparent order of the clay layers in the T5000-MMT/epoxy nanocomposite, transmission electron microscopy (TEM) revealed the presence of multiplets with an average size of 5,nm and the average spacing between multiplets falls in the range of 100 Å. The multiplets clustered into mineral rich domains with an average size of 140,nm. Scanning electron microscopy (SEM) reveals the absence of mineral aggregate. Nanocomposites exhibit significant increase in thermal stability in comparison to the original epoxy. The effect of the organoclay on the hardness and toughness properties of crosslinked polymer matrix was studied. The hardness of all the resulting materials was enhanced with the inclusion of organoclay. A three-fold increase in the energy required for breaking the test specimen was found for T5000-MMT/epoxy containing 7,wt% of organoclay as compared to that of pure epoxy. Copyright © 2004 John Wiley & Sons, Ltd. [source] | ||||||||||