Electrospun PMMA/AB nanofiber composites for hydrogen storage applications

Abstract

In this work, poly(methyl methacrylate) (PMMA)/ammonia borane (AB) nanofiber composites were fabricated and the synergetic nanoconfinement effect of nanofibers on dehydrogenation temperature and the removal of unwanted by-products of AB (NH3 BH3) were studied. The results of the dehydrogenation of PMMA/AB samples showed an exothermic reaction temperature of 112°C, which is significantly lower than that of pure AB (120°C). Furthermore, the interaction between AB molecules and PMMA nanofiber structures decreased the enthalpy of exothermic decomposition, from -21.00 to -10.66 kJ/mol H2, suggesting that this type of AB nanofiber composite can provide a convenient reversible hydrogen storage material. Based on the thermogravimetric analysis curves, the use of PMMA to support AB in composite structures resulted in a decrease in AB weight loss from 60.00 to 11.10 wt.% which, in turn, could vigorously reduce the emission of by-product impurities. Based on the obtained results, the strategy of supporting AB in nanofiber structures can be presented as a practical solution to maintain lower operational temperatures and to reduce undesirable volatile products in the dehydrogenation process of AB.

Ammonia Borane: An Extensively Studied, Though Not Yet Implemented, Hydrogen Carrier

“…The ammonia borane nanophase was in the form of 4-nm nanoparticles, and released pure hydrogen from 50 • C. A last synthetic approach is nanostructuration by electrospinning, where nanofibers of a polymer encapsulating ammonia borane are elaborated. Useful polymers for that purpose are polystyrene [284], polyvinylpyrrolidone [285], poly(methyl methacrylate) [286], polyethylene oxide [287] and polyacrylamide [288]. In each case, embedded ammonia borane nanophase showed improved dehydrogenation properties in comparison with the bulk counterpart, but the release of some ammonia, diborane and/or borazine could not be avoided.…”

Improvement of sciatic nerve regeneration by multichannel nanofibrous membrane-embedded electro-conductive conduits functionalized with laminin

“…The PCL channel which provides a barrier between the healing nerve and surrounding media was fabricated from nanofibers with relatively non-uniform distribution. Previous studies revealed that the electrospun solution condition (including viscosity, charge density and shear stress) and solvent vapor pressure can simultaneously affect the fiber diameter distribution [ 52 ]. Another parameter which can affect fiber distribution is collector rotation.…”

Optimization of mechanical and biocompatible properties of ZnOs-fiber membranes

“…The FESEM images of (PVA+CS)+ZnO NPs electro-spun fibers at different magnifications are shown in Figure 3. The fibers presented a smooth surface compared to the polymer fibers without nanoparticles, average diameter of PVA/CTS/ZnO NP fibers was 100.8 nm, more significant than the average diameter of the polymer fibers without nanoparticles Figure 3A there for when the nanofiber diameter increased by increasing the weight concentration of NP because agglomeration of nanoparticles [23].…”

“…Favorable mechanical properties, whereas added 0.4, 0.6 ZnO nanoparticles tend to cluster inside the (PVA+CS) matrix due to these aggregated nanoparticles acting as stress concentration sites. Moreover, the aggregated nanoparticles hinder the (PVA+CS) chains' mobility, which lowers the nano composites' elongation at the break, for a high concentration of ZnO reduced mechanical properties [23]. 5, displays the Hardness results.…”