Determination of epoxy coating wet-adhesive strength using a standardized ASTM/ISO scratch test

Abstract

A new approach for evaluating the wetadhesive strength of epoxy-based coatings was carried out based on a recently standardized ASTM/ISO scratch test. A linearly increasing scratch normal load was applied during scratch to induce progressively increased delamination stress at the coating and steel substrate interface. Thus, the applied critical load to cause coating debonding can be experimentally determined. To find out the corresponding stress magnitude to incur coating debonding, finite element methods (FEM) modeling was conducted to analyze the stress fields around the scratch tip during scratching. The wet-adhesive strength is then quantitatively determined. Based on the above methodology, investigation on a set of model coating systems suggests that the critical load for coating delamination is significantly influenced by water exposure time, coating thickness, and substrate surface roughness. By combining the standardized scratch tests and FEM modeling, the proposed approach is found to be effective for quantitative assessment of epoxy coating wet-adhesive strength and for the development of high performance protective coatings for various industrial applications.

Interfacial Phenomena and Mechanical Behavior of Polyetheretherketone/Polybenzimidazole Blend under Hygrothermal Environment

“…Polymer blending provides a versatile approach to develop new material systems with the beneficial features of each component. , However, the development of new useful blends is significantly limited by the incompatibility of many polymer pairs of interest . The extended Flory–Huggins theory has demonstrated that there are substantial thermodynamic barriers to obtaining a one-phase polymer blend at a molecular level. − Most polymer pairs are immiscible at ambient temperature and form multiphase systems whose bulk properties are governed by the properties of the interface between the phases. − The interface of incompatible polymer blends tends to exhibit low mechanical strength during large deformation and fracture because of the lack of physical and chemical bonding across the phase boundaries. ,,− As a result, manipulation of interfacial bonding in binary or multicomponent polymer systems is of particular interest to better control or predict their physical and mechanical properties . Fundamental knowledge is needed for successful preparation of polymer blends.…”

Experimental observation and finite element method modeling on scratch‐induced delamination of multilayer polymeric structures

“…[ 3 ] It has been found that the resistance to scratch‐induced delamination and the interfacial failure mode in various types of polymeric laminates can be different. [ 4,5 ] For example, it has been shown that Mode I dominant delamination occurred on epoxy‐coated steel. [ 5 ] A typical Mode II‐dominated delamination took place in some multilayer acrylate coatings upon scratching.…”

“…[ 4,5 ] For example, it has been shown that Mode I dominant delamination occurred on epoxy‐coated steel. [ 5 ] A typical Mode II‐dominated delamination took place in some multilayer acrylate coatings upon scratching. [ 6 ] A mixed‐mode delamination was observed between the blow‐molded top polyethylene terephthalate layer and the adjacent nylon layer.…”

“…[ 2,17,18 ] It has been shown that the base layer polymer thickness and constitutive behaviors are equally important in affecting the delamination behavior. [ 3,5 ] For example, a blow‐molded tri‐layer polymeric system with a PET base layer exhibits a higher delamination resistance than that with a nylon base layer even though the top layer of both laminates is the same. [ 3 ] Therefore, it is necessary to carry out a comprehensive study to understand how the delamination between the polymeric laminates is influenced by both top and base layer thicknesses and constitutive properties.…”

Experimental and numerical investigations of evaluation criteria and material parameters' coupling effect on polypropylene scratch

“…For the applications where the visual perception is preferred, it is very important to find the suitable criteria to quantitatively determine the scratch resistance of polymers . The optical methods, e.g., the grey level and the Delta‐L method , have been adopted to determine the scratch resistance of polymers.…”