scholarly journals Effect of Exposure Conditions on the Interfacial Bond Properties of SS400 Plate Coated with Various Epoxy Resins

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1159
Author(s):  
Sungwon Kim ◽  
Hyemin Hong ◽  
Jun Kil Park ◽  
Sangmin Park ◽  
Seoung Ik Choi ◽  
...  

This study aims to investigate the effects of different exposure conditions on the interfacial bond between steel plates and epoxy resin coatings at early ages. Test variables include the epoxy resin types, exposure conditions, exposure periods, and coating equipment. The selected epoxy resins were applied to prepared steel plates and cured at each exposure condition for 7, 28, 56, or 91 days, and the pull-off bond strength and coating thickness were measured. Scanning electron microscopy (SEM) images were obtained to study the interfacial bond for some representative coatings. Three different exposure conditions (indoors and actual marine environment) were considered in this study. This study is also focusing on the improvement of previously developed underwater coating equipment and evaluating the performance. Experiments were conducted to evaluate the performance of the improved equipment types under different environmental conditions: indoors (tap water and seawater) and outdoor conditions. The improved equipment types were confirmed to be effective for underwater coating and easier to use than the previous equipment under real sea conditions. The experimental results also confirmed that the bond strength of the coating decreased as the curing time increased.

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3715 ◽  
Author(s):  
Boreum Won ◽  
Min Ook Kim ◽  
Sangmin Park ◽  
Jin-Hak Yi

Interfacial bond properties of six different epoxy resins used to coat submerged concrete structures were investigated. Test variables included coating type, coating equipment, and underwater curing time. Coating thickness and pull-off bond strength were measured using commercially available test equipment. Coating thickness and bond strength varied greatly depending on the manufacturer. The standard (control) coating equipment positively influenced the bond strength compared to other equipment. The effect of curing time on the bond properties was not significant within the range of 24 to 72 h. Lastly, some important considerations for the underwater coating of actual marine and coastal concrete structures were discussed, and suggestions for future research are presented.


Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 757 ◽  
Author(s):  
Kim ◽  
Hong ◽  
Han ◽  
Kim

In this study, coating equipment for the effective underwater repair of submerged structures was developed. The tensile bond characteristics of selected epoxy resin coatings were investigated by coating the surface of a specimen using each of the four types of equipment. Using the experimental results, the tensile bond strength and the coating thickness were analyzed according to the type of equipment, coating, and curing time. The results show that the type of coating equipment used had the greatest effect on the measured bond strength and coating thickness of the selected coatings. However, the effect of coating type and curing time on the bond strength and the thickness was observed to be insignificant. Compared with the developed equipment, the surface treatment of the coating was observed to be more effective when using the pre-existing equipment, and thus the bond performance of the coating was improved compared to using the pre-existing equipment. Based on the experimental results, improvements and needs involving the equipment for further research were discussed.


2000 ◽  
Vol 9 (3) ◽  
pp. 096369350000900 ◽  
Author(s):  
E. Mδder ◽  
X.-F. Zhou ◽  
E. Pisanova ◽  
S. Zhandarov ◽  
S. R. Nutt

Interfacial bond strength between epoxy resin and glass fibre was studied using the pull-out and push-out techniques. For untreated fibres, these micromechanical tests gave similar values of the local interfacial shear strength and critical energy release rate. In the case of fibres treated by γ-APS, both tests showed considerable increase in the bond strength. However, for the modified fibres, the pull-out test gave greater values of both interfacial parameters than the push-out test, a result attributed to the different modes of interfacial loading. The different loading patterns also cause different failure mechanisms in these two tests.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Nannan Sun ◽  
Yifan Song ◽  
Wei Hou ◽  
Hanhao Zhang ◽  
Datong Wu ◽  
...  

It is necessary to pay attention to the bonding strength of the interface between precast normal strength concrete (NSC) and cast-in-place epoxy resin concrete (EMR) when using EMR as a repair or filling material or an overlay in bridges’ rehabilitation. However, the performances of epoxy concrete are different due to differential mix ratios; thus, the bonding properties between various epoxy resin concrete and cement concrete are not completely the same. This article investigated the interfacial bond properties between NSC and ERC by direct tensile, push-out, and slant shear test with specimens of special size and structure and observed the interfacial bond strength and corresponding failure modes. The minimum bond strength under direct tension was 0.72 MPa, while the minimum bond strength was 1.71 MPa and 3.19 MPa for the push-out test and slant shear test, respectively. Results indicated that the slant shear test specimens with an inclination angle of 45° are not suitable for the slant shear test due to higher compressive stress. Furthermore, the cohesion and friction coefficient of interface bond strength were calculated inversely in accordance with the results obtained from the corresponding direct tensile and slant shear tests. The minimum cohesion value was 1.71 MPa, and the minimum friction coefficient value was 0.46.


Author(s):  
J. G. Adams ◽  
M. M. Campbell ◽  
H. Thomas ◽  
J. J. Ghldonl

Since the introduction of epoxy resins as embedding material for electron microscopy, the list of new formulations and variations of widely accepted mixtures has grown rapidly. Described here is a resin system utilizing Maraglas 655, Dow D.E.R. 732, DDSA, and BDMA, which is a variation of the mixtures of Lockwood and Erlandson. In the development of the mixture, the Maraglas and the Dow resins were tested in 3 different volumetric proportions, 6:4, 7:3, and 8:2. Cutting qualities and characteristics of stability in the electron beam and image contrast were evaluated for these epoxy mixtures with anhydride (DDSA) to epoxy ratios of 0.4, 0.55, and 0.7. Each mixture was polymerized overnight at 60°C with 2% and 3% BDMA.Although the differences among the test resins were slight in terms of cutting ease, general tissue preservation, and stability in the beam, the 7:3 Maraglas to D.E.R. 732 ratio at an anhydride to epoxy ratio of 0.55 polymerized with 3% BDMA proved to be most consistent. The resulting plastic is relatively hard and somewhat brittle which necessitates trimming and facing the block slowly and cautiously to avoid chipping. Sections up to about 2 microns in thickness can be cut and stained with any of several light microscope stains and excellent quality light photomicrographs can be taken of such sections (Fig. 1).


Author(s):  
Georgel MIHU ◽  
Claudia Veronica UNGUREANU ◽  
Vasile BRIA ◽  
Marina BUNEA ◽  
Rodica CHIHAI PEȚU ◽  
...  

Epoxy resins have been presenting a lot of scientific and technical interests and organic modified epoxy resins have recently receiving a great deal of attention. For obtaining the composite materials with good mechanical proprieties, a large variety of organic modification agents were used. For this study gluten and gelatin had been used as modifying agents thinking that their dispersion inside the polymer could increase the polymer biocompatibility. Equal amounts of the proteins were milled together and the obtained compound was used to form 1 to 5% weight ratios organic agents modified epoxy materials. To highlight the effect of these proteins in epoxy matrix mechanical tests as three-point bending and compression were performed.


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