Search results for "ciencia de los materiales"
showing 5 items of 35 documents
Proton Conducting Electrospun Sulfonated Polyether Ether Ketone-Graphene Oxide Composite Membranes
2017
[EN] A series of novel composite membranes, based on sulfonated poly(ether ketone) (SPEEK) with a graphene oxide (GO) layer, were prepared. One contained a GO layer sandwiched between the SPEEK-polyvinyl alcohol (PVA) matrix (SPEEK/PVA@GO), and another deposited thin layers of GO on the nanofibers of SPEEK-polyvinyl butyral (PVB), with both sandwiched in the phase matrix of SPEEK-PVA (SPEEK/PVA@GO-NF). Various nanofiber thicknesses were studied by varying the electrospinning time. The prepared composite membranes with different nanofiber thicknesses were characterized by scanning electron microscopy, water uptake, ionic exchange capacity, thermogravimetric analysis, mechanical properties an…
Electrospun Poly(ethylene-co-vinyl alcohol)/Graphene Nanoplatelets Composites of Interest in Intelligent Food Packaging Applications
2018
Graphene nanoplatelets (GNPs) were synthetized from graphite powder and, thereafter, embedded in poly(ethylene-co-vinyl alcohol) (EVOH) fibers by electrospinning in the 0.1&ndash
Functionalised poly (vinyl alcohol)/graphene oxide as polymer composite electrolyte membranes
2019
[EN] Crosslinked poly(vinyl alcohol) (PVA) based composite films were prepared as polyelectrolyte membranes for low temperature direct ethanol fuel cells (DEFC). The membranes were functionalised by means of the addition of graphene oxide (GO) and sulfonated graphene oxide (SGO) and crosslinked with sulfosuccinic acid (SSA). The chemical structure was corroborated and suitable thermal properties were found. Although the addition of GO and SGO slightly decreased the proton conductivity of the membranes, a significant reduction of the ethanol solution swelling and crossover was encountered, more relevant for those functionalised with SGO. In general, the composite membranes were stable under …
Laser Cladding of TiC for Better Titanium Components
2011
Pure commercial titanium is widely used because of its high corrosion resistance and lower cost compared with other titanium alloys, in particular when there is no high wear requirements. Nevertheless, the wear resistance is poor and surface damage usually occurs in areas under contact loadings. Laser cladding is a suitable technique for manufacturing precise and defect free coatings of a dissimilar material with higher wear and corrosion resistance. In this work a good understanding of laser metal deposition mechanisms allowed to obtain defect free coatings of Ti6Al4V and TiC metal matrix composite (MMC) using a flash lamp pumped Nd:YAG laser of 1 kW. A complete investigation of the proces…
Tailored electrospun nanofibrous polycaprolactone/gelatin scaffolds into an acid hydrolytic solvent system
2018
[EN] Blended nanofibrous scaffolds based on polycaprolactone (PCL) and gelatin (Ge) were successfully prepared. A formic/acetic acid (1:1) mixture was used to dissolve PCL/Ge blends from 100/0 to 20/80 %wt in steps of 10 %wt. The hydrolysis of the PCL diluted in the formic/acetic acid mixture was considered as a method for tailoring the surface morphology and physicochemical features of the nanofibrous PCL/Ge scaffolds as a function of the dissolution time. The fibre diameter remained in the nanoscale range for all the studied scaffolds, which is crucial to mimic the extra-cellular matrix size. The reduction of the intrinsic viscosity, molar mass and hydrodynamic radius found for the PCL mo…