BACKGROUND Epoxy products are among the most common causes of occupational allergic contact dermatitis. Diglycidyl ether of bisphenol A resin (DGEBA-R) is the most important sensitizer in epoxy systems. OBJECTIVES To describe patients with occupational allergic contact dermatitis caused by epoxy products. METHODS Patients with allergic reactions to epoxy chemicals were chosen from test file...

The molecular mobility related to the glass transition and secondary relaxations in a hyperbranched polyethyleneimine, HBPEI, and its relaxation behaviour when incorporated into an epoxy resin matrix are investigated by dielectric relaxation spectroscopy (DRS) and dynamic mechanical analysis (DMA). Three systems are analysed: HBPEI, epoxy and an epoxy/HBPEI mixture, denoted ELP. The DRS behavio...

The propagation of electrical trees along interfaces in epoxy resin is described. The electrical trees grew in needle-plane samples without and with internal barriers up to the final breakdown. The barrier materials glass, mica and PTFE had been chosen because they have significantly different bond mechanisms to the epoxy resin as well as being common materials in various composite high voltage...

A phenomenon that is typical in dc insulation is the accumulation of space charge which can significantly enhance the local electric field. This phenomenon is of special importance for polymeric insulation. Accumulation of space charge proved to be a limiting factor for HVDC applications. The goal of this paper is to show the different behavior of epoxy nanocomposites under various dc field str...

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In this paper, a synthesis method of epoxy resin toughening agent was presented, then the chemical composition and molecular number were studied, which include the DSC curves analysis, the fracture surface morphology and bonding strength. In addition, the mechanism of epoxy resin toughening agent and the effect of toughening agent's content to bonding strength were studied. The testing results ...

In this study, we used diglycidyl ether bisphenol A (DGEBA) as a matrix, the ABA block copolymer poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) (Pluronic F127) as an additive, and diphenyl diaminosulfone (DDS) as a curing agent to prepare flexible epoxy resins through reaction-induced microphase separation (RIMPS). Fourier transform infrared spectroscopy confirmed the existence of hydr...

How chemical structure changes affect the curing reactions and thermal properties of 2,2 -bis(4-cyanatophenyl) propane (cyanate ester) cured rigid-rod epoxy resins has been studied for biphenol and tetramethyl biphenol epoxies. The formation of an oxazolidinone ring is the dominant curing reaction for biphenol epoxy, whereas the formation of a cyanurate ring is the dominant curing reaction for ...

Non covalent functionalization by π stacking was accomplished by treating multi walled carbon nanotubes (MWNTs) through the use of Kentera, a conjugate rigid rod polymer. The functionalized MWNTs were then introduced into the epoxy resins through a combination of shear and elongation forces. The resulting epoxy resin (containing MWNTs) was then impregnated with carbon fiber under hot-melt condi...

The use of additives to improve the quality of cement grouts is crucial for civil engineering, especially in foundation construction. This article presents experimental data concerning the compressive strength, elastic modulus, bleeding and injectability of microfine cement grouts modified with epoxy and acrylic resin emulsions. Strength properties were obtained at different curing ages. For fu...