• Elastomers and Composites
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• v.48 no.4
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• pp.288-293
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• 2013

Crosslink characteristics of maleic anhydride-grafted EPDM (MAH-g-EPDM)/zinc oxide composite were investigated by weight losses after dichloroacetic acid (DCA)/toluene cosolvent extraction at different temperatures and by measurement of crosslink densities. The chemical changes were analyzed using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The weight losses by extraction at high temperature ($90^{\circ}C$) were remarkably greater than those at room temperature and those by DCA/toluene cosolvent extraction were greater than those by toluene one by more than 5 times. The crosslink densities were measured after the solvent extraction, and the second crosslink densities were higher than the first ones. The first crosslink density was lower when the extraction temperature was high, and it was much lower for the toluene extraction than for the DCA/toluene cosolvent extraction. The second crosslink density of the sample extracted with DCA/toluene cosolvent was greater than that extracted with toluene. The extracted components were depending on the extraction solvents and temperatures, for example; only strong crosslinked networks were remained when extracting with DCA/toluene cosolvent at high temperature, while only uncrosslinked polymer chains were extracted when extracting with toluene at room temperature. Therefore, crosslink characteristics of the MAH-g-EPDM/zinc oxide composite can be analyzed by comparison of the extracted components according to the extraction solvents and temperatures and by measurement of successive crosslink densities.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.179-186
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• 2006

In this study, Multi-Layer Perceptron(MLP) among models of Artificial Neural Network(ANN) is used for the development of a model that evaluates the bending capacities of reinforced concrete beams strengthened by FRP Rebar. And the data of the existing researches are used for materials of ANN model. As the independent variables of input layer, main components of bending capacities, width, effective depth, compressive strength, reinforcing ratio of FRP, balanced steel ratio of FRP are used. And the moment performance measured in the experiment is used as the dependent variable of output layer. The developed model of ANN could be applied by GFRP, CFRP and AFRP Rebar and the model is verified by using the documents of other previous researchers. As the result of the ANN model presumption, comparatively precise presumption values are achieved to presume its bending capacities at the model of ANN(0.05), while observing remarkable errors in the model of ANN(0.1). From the verification of the ANN model, it is identified that the presumption values comparatively correspond to the given data ones of the experiment. In addition, from the Sensitivity Analysis of evaluation variables of bending performance, effective depth has the highest influence, followed by steel ratio of FRP, balanced steel ratio, compressive strength and width in order.