Mechanical characteristics of tire/clay modified epoxy used in fabrication of medical prostheses and artificial human parts
Epoxy is used in many dental and medical applications such as manufacturing prostheses. This polymer is not toxic and is a good candidate for easily forming of artificial hand, leg, etc. In recent years, the recycled waste tire has been concerned as inexpensive modifier for improving the toughness characteristics of many thermoset resins such as epoxy. Herein, the influence of addition of nanoclay on mechanical characteristics of waste tire-modified epoxy was investigated. Mechanical properties i.e. compressive and flexural characteristics, fracture toughness and impact strength of the samples were investigated. The fracture surfaces of the specimens were examined using scanning electron microscope (SEM). Moreover the glass transition temperature (T ) of the samples were measured. Results reveal that nanoclay can improve the g mechanical characteristics of waste tire-modified epoxies.
Thin films of epoxy adhesives containing recycled polymers and graphene oxide nanoflakes for metal/polymer composite interface
Abstract Epoxy adhesives based on recycled poly(ethylene terephthalate) (PET), ground rubber tire (GTR), and graphene oxide (GO) nanoflakes were designed and their thermal and mechanical properties were discussed. By changing the amounts of the aforementioned components (recycled polymers and GO nanosheets), adhesive formulations were tested for tensile and single-lap shear strength applied at the interface between epoxy/carbon fiber and stainless steel. The best and the worst samples in regard to mechanical strength were specified and selected for thermal degradation analyses base on thermogravimetric analysis (TGA). The dispersion state of PET and GTR were also studied by the use of field-emission scanning electron microscopy (FE-SEM). It was found that addition of 10 phr of 75/25 (w/w) PET/GTR mixture to 100 parts by weight of epoxy together with 0.1 phr of GO could surprisingly enhance ca. 29, 260 and 585% the Young’s modulus, tensile strength, and the toughness of epoxy, respectively. It was also proved that introduction of GO to the adhesive enhanced thermal stability of epoxy/(PET/GTR).
The role of dissolved oxygen in supercritical water in the oxidation of ferritic–martensitic steel
Abstract To assess the role of dissolved oxygen in supercritical water on the growth processes of oxide scales, a marker experiment of ferritic–martensitic steel was performed by exposing to supercritical water (H 2 16 O) containing marked 18 O 2 at 600 °C under 25 MPa. The oxide scale was analysed by using Secondary Ion Mass Spectrometry (SIMS). The oxygen isotope profile shows that dissolved oxygen and supercritical water react with metals simultaneously. Dissolved oxygen changes the oxidation/reduction potential of supercritical water leading to an increase in the oxidation rate. The oxidation rate increases with increase in dissolved oxygen content in supercritical water. The mechanism of the effect of dissolved oxygen on oxidation is discussed.