Epoxy-clay nanocomposites were prepared by applying high- intensity ultrasound during the synthesis of clay-epoxy nanocomposites by two kinds of amineous curing agent, cycloaliphatic and amidoamine. Exfoliation and intercalation of nanoclay have a significant effect in improvement of physical and chemical epoxy coatings properties. The choice and condition of curing agent controls the contribution of nanoclay of these coatings.In this article, X-ray diffraction (XRD), Optical microscopy and Scanning Elecron Spectroscopy (SEM) analyses were carried out. The results of XRD showed that the distances between the silicate layer were increased from 18.02 Ao to 38.5 and 41.6 Ao, in two coating systems. The results of Scanning Elecron Spectroscopy (SEM) showed the nanoclay particles in the polyamidoamine coating are composed of 3% of nano with flake structure that increase the direction of the ions in the time of getting the metal surface. The result of optical microscopy also shows the appropriateness of the ultrasound method in preparing nanocomposits. By using the results of Electrochemical Impedance (EIS)and Salt spray, the corrosion resistance of nanocomposites were obtained. From electrochemical impedance spectroscopy, it was observed that nanocomposite coating epoxy-polyamidoamine, with the formulation consisting of 3% nanoclay had the excellent corrosion resistance in comparison to pure epoxy coating.

In this study, the effect of open time and hardener content was investigated on bending strength of finger jointed made of three wood species; beech, fir and poplar. For this purpose, wooden samples with dimensions of 25mm width, 35 mm thickness and 350 mm length were prepared from three species. After three weeks of storage in climate room, in order to form finger joint pattern, samples were cut at the half of length. Then, the finger joint pattern was done in new exposed cross sections of the samples. After that, the joints were bonded with three PVAc glue types; pure, with 10% and with 20 % hardener. The second variable of study was open time that was controlled in two levels of 2 and 4 minutes. The close time and press time were constant which were adjusted on 2 and 30 minutes, respectively. The joints were pressed in a special wooden frame by hand clamp. After making joints, they were stored in climate room for three weeks and then the three point bending test was carried out according to ISO 10983. The results showed that by adding isocyanate hardener up to 20%, the bending strength increases significantly. The longer open time could not improve bending strength. On the contrary, it caused strength dropping in some treats but these changes were not significant. The strength of joints made with poplar wood was lower than beech and fir, although this difference was not statistically significant. Finally, the best condition for making this joint was determined by application of 2 min open time and using 10 % PU resin as a hardener.

In this study, Polyester Resin was used as a fixing material for fixing aquatics samples for education uses and that have advantages such as not having stink, anti-Carcinogen, stability of color, easy transportation and more durable than actual common methods which are used to keep samples in Formalin solution. Hence, first proper dosage of a stiffener that must be mixed with Resin was Resin and finally they compared three methods by using scoring to the most important factors which can be significant in stabilization of sample. In the first method, fresh fish was used in Resin which can be utilized just for small fish. In the second method, Formalin was used before putting samples in Resin, but achieved results show a kind of blurring in samples. In the third method, acetone was used as an absorbing material after stabilization of samples by Formalin that has better results rather that former two of hers methods that prepares samples with higher clearance and lower blurring and being more homogeneous compared to her two former methods.

In steel structures, connections play an important role in the behavior of the structure. In this article, by using numerical modeling with Abaqus finite element software, several different models of beam to steel column connection have been modeled and investigated. This article has investigated the effect of beam-to-column connection with two types of shield and corner connection. Hence, 20 models with different conditions of different thicknesses and different types of hardeners, as well as 6 models with columns filled with concrete, have been investigated and studied. Abaqus finite element software is used for modeling and cyclic load is used for loading. The results show that the model with the shield stiffener had a higher capacity and compared to the corner stiffener, it had a 12-28% higher bending capacity in the connection. By increasing the thickness of the corner or shield of the beam to the column connection, the capacity has increased by about 12 to 25%, in the thickness of 18 mm, the anchor capacity has increased by 12%, and in the thickness of 20 mm, it has been observed to increase by 25%. The column model filled with concrete has a difference of 15-25% compared to the similar model without concrete, and the column model filled with concrete has a higher bearing capacity.

In this study, effective parameters for Polymer Concrete (PC) based on epoxy resin such as  filler, hardener, and solvent are investigated. Rice husk and broom stem ashes as  fillers with a mixture of 50{50% acetone-toluene as solvent in the preparation of PC samples were used. According to experimental results, the addition of  fillers improved compressive, flexural, and chemical strengths of the PC samples. In the sample with 18. 4% polymer, given the addition of rice husk ash with a ratio of  filler-aggregate 0. 075, compressive strength improved by 21%. For the sample with the broom stem ash ratio of  filler-aggregate 0. 09, the flexural strength improved by 27%. In addition, experimental data proved that the addition of optimum amount of solvent improved the performance and enhanced the compressive and flexural strengths. However, the excess amount of solvent may reduce the adhesiveness of the polymer; therefore, it may have negative impact on PC. The combination of hardener-resin may affect the strength of PC. Amine type of hardener with a low equivalent weight improved by 27% and 13% on compressive and flexural strengths. Moreover, elasticity modulus increased compared with the samples having a high equivalent weight of amine type hardener.

In this paper the effect of Epoxy Resin polymer on moisture sensitivity of Asphalt mixtures containing Silica and limestone aggregates has been evaluated. Epoxy Resin without hardener and Epoxy Resin curing with hardener in 0، 1، 2، 3، 4، and 5 weight percentages for Asphalt Binder modification have been applied. The method used for evaluating moisture sensitivity of Asphalt mixtures is Surface Free Energy method. In this method، with Surface Free Energy measurements of Asphalt Binder using Sessile Drop method and by using of the extracted values of Surface Free Energy of aggregates of valid reports، the energy parameters related to moisture sensitivity of Asphalt mixtures containing Asphalt Binder and aggregates compound، have been calculated and analyzed. At the end، base and modified Asphalt Binders with Epoxy Resin curing with hardener have been examined with FTIR test. The results show that the Epoxy Resin curing with hardener decreases moisture sensitivity of Asphalt mixtures containing Silica and limestone aggregates. Epoxy Resin without hardener does not have important effect on Asphalt mixtures containing limestone aggregates، but decreases moisture sensitivity of Asphalt mixtures containing Silica aggregates.

Epoxy resins are widely used in composites, aerospace, construction, electronic, adhesive and coatings industries due to their high physical and mechanical, thermal resistance, electrical and chemical properties. For curing epoxy resins, a chemical material, called curing agent or hardener, must be used. Curing agents have strong effect on the processing conditions and final properties of the cured resins. In general, epoxy curing agents can be classified in two groups of normal (room or high temperature) and latent curing agents. Normal curing agents increase the resin viscosity at room temperature due to crosslinking or curing reactions and the resin is gelled and finally cured. The rate of viscosity increment would be different and depends on the kind of curing agent. On the other hand, latent curing agents cannot react with epoxy resin at room temperature and do not increase the resin viscosity. Therefore, they are being used for preparing one-part epoxy resins. Latent curing agents are not active at room temperature, but they will react with epoxy resin by the application of an external force like heat or light. Thermally-latent curing agents are well-known and they are widely used. They include substances with active hydrogen, and are catalyzed and protected by chemical groups and microcapsules. Selection of a latent curing system for an application is an important issue which affects the processing conditions and final properties of the cured resins. In this paper, the latest achievements in this area are reviewed.

The reaction mechanism of metal-containing and complex compound with epoxy oligomer of diglycidyl ether of bisphenol A (DGEBA) was studied using dynamic DSC technique, it is shown that cure reaction of the epoxy oligomers with copper acetate proceeds at two stages: through the coordination of the cation with the epoxy group, and through ionic polymerization at high temperatures. The mechanism of curing of DGEBA with the copper chelate depends on the equilibrium process of dissociation of the chelate which, in turn, depends not only on the temperature of curing but also on the concentration of the hardener. At the dissociation temperature of the hardener, the polymerization proceeds according to ionic mechanism. Hardening of the epoxy oligomers due to interaction of the epoxy groups with the unconnected amine group predominates at higher temperatures or at higher concentrations of the hardener. At tow temperatures and small concentrations of the hardener, the polymerization proceeds according to the catalytic ionic mechanism.

In this study, in order to gain the best Particleboard made of production, the effect of three factors, resin content, hardener content, and press time on the static bending strength, Internal board, water absorption, and thickness swelling after 2, and 24 hrs. Immersion in water of boards mades are studied. 54 boards were made and after measuring of their physical and mechanical, the results was analyzed with using the factorial completely randomize design.The results show that increasing resin content causes better quality of properties of boards such as bending strength, Internal bound, and dimensional stability.Increasing of press time from 5 to 5.5 min. Causes better bending strength, Internal board and dimensional stability of boards where, with increasing of press time from 5.5 to 6 min are observed that all of the mechanical properties of boards were reduced.Totally speaking, it can be noted that changing of bending properties, internal bound, water absorption, and thickness swelling after 2, and 24 hrs. Immersion in water of boards made show that optimum condition are 11% resin, 2% hardener, and 5.5 min press time for making particle board made of Bagasse.