جستجوی مقالات مرتبط با کلیدواژه « CNF » در نشریات گروه « مواد و متالورژی »

Electrospinning, stabilization and carbonization are three steps of synthesizing electrospun carbon nanofibers (CNF), using polyacrylonitrile (PAN) precursor. In this study, the effect of the stabilization temperature was studied on the morphology and chemical state of the electrospun PAN fibers, which were later carbonized to produce carbon nanofibers. the stabilization was carried out on electrospun PAN fibers, at different temperatures of 230 °C, 240 °C, 250 °C and 280 °C for 2h with a heating rate of 2 °C/min. Fourier transform infrared spectroscopy was used to inspect the progress of stabilization reactions. The crystallinity and composition was studied by X ray diffraction and scanning electron microscopy was used to observe the morphology of the fibers. The results showed that 230 oC is the best stabilization temperature in which not only all expected reactions take place but also the fibrous morphology is preserved. Higher temperatures led to destruction of the fibrous morphology.

In this study, carbon nano fibers (CNFs) were mixed into epoxy resin through a magnetic stirrer and again mixed using ultra sonicator. Using hand layup technique, biaxial braided fiber composites were prepared with unfilled, 0.2, 0.5 and 1 wt% CNF. Tensile test and shear test was performed to identify the tensile strength and shear strength of the composites. Fractured surface of the tensile specimens were examined by scanning electron microscopy to identify morphologies of nanoparticles. A discrete three layer model was developed for prediction of the tensile modulus and shear modulus of biaxial braided fiber composites. Theoretical and experimental values were compared. The experimental and theoretical results show that the addition of CNF in the epoxy matrix had significant influences on the mechanical properties of biaxial carbon braided fiber composites. CNF inclusion with braided composite promoted the tensile modulus, tensile strength, shear modulus and shear strength up to 0.5wt% of the biaxial carbon braided fiber composites.