Sharif Digital Repository

Thermal degradation behavior of multi-wall carbon nanotubes (MWCNTs)/ultra high molecular weight polyethylene (UHMWPE) nanocomposites, with different nanotubes contents (0.5, 1.5 and 3.5 wt%) prepared via in-situ polymerization technique have been investigated using thermal gravimetric analysis (TGA). TGA spectra revealed that these nanocomposites had enhanced thermal stability and no significant mass loss (<0.4 wt%) occurred up to 350°C. Thermal degradation of these UHMWPE/MWCNT nanocomposites was investigated in terms of parameters such as the onset temperature of degradation (T 10), the decomposition temperature at 50% wt loss (T 50), the degradation temperature of maximum rate of the... 

Curing of thermoset-based composites experience substantial temperature overshoot, especially at the center of thick parts and large temperature gradient exists through the whole part due to large amount of heat released and low conductivity of the composite. This leads to non-uniformity of cure, residual stress and consequently composite cracks and possibly degradation of the polymer. The scope of this work is to optimize the cure cycle in order to improve the properties and gaining a relatively uniform part of composite, using trained recurrent artificial neural networks purposed for speeding up the repetitious model re-calls during the optimization process. Numerical results obtained... 

In this study, polyethersulfone (PES)-based nanocomposite membranes with the incorporation of inorganic filler of α-alumina were prepared via thermal phase inversion method. The fabricated flat sheet-mixed matrix membranes were characterized using X-ray diffraction, thermal gravimetric analysis, differential scanning calorimetry, scanning electron microscopy, and atomic force microscope analysis, and the permeation tests were performed for hydrogen, nitrogen and carbon dioxide. Also prepared α-alumina particles were identified by X-ray diffraction and the surface area, total pore volume and average pore diameter of particles were measured with a high-speed gas-sorption analyzer. The...