RESUMEN
This work offers an ecologically friendly and facile approach for the modification of high-tonnage commercial polymers, including polypropylene (PP), high-density polyethylene (HDPE), and poly(ethylene terephthalate) (PET), and preparation of nanocomposite polymeric membranes via incorporation of modifying oligomer hydrophilic additives, such as poly(ethylene glycol) (PEG), poly(propylene glycol) (PPG), polyvinyl alcohol (PVA), and salicylic acid (SA). Structural modification is accomplished via the deformation of polymers in PEG, PPG, and water-ethanol solutions of PVA and SA when mesoporous membranes are loaded with oligomers and target additives. The content of target additives in nanocomposite membranes is controlled by tensile strain, and the level of loading can achieve 35-62 wt.% for PEG and PPG; the content of PVA and SA is controlled by their concentration in the feed solution. This approach allows for the simultaneous incorporation of several additives which are shown to preserve their functional performance in the polymeric membranes and their functionalization. The porosity, morphology, and mechanical characteristics of the prepared membranes were studied. The proposed approach allows an efficient and facile strategy for the surface modification of hydrophobic mesoporous membranes: depending on the nature and content of target additives, their water contact angle can be reduced to 30-65°. Water vapor permeability, gas selectivity, antibacterial, and functional properties of the nanocomposite polymeric membranes were described.
RESUMEN
Ultra-high-pressure hydrogen-storage performance (up to 1900â bar) was investigated for mesoporous chromium terephthalate MIL-101 and its inclusion compounds containing ionic clusters [Re(4)S(4)F(12)](4-) and [SiW(11)O(39)](7-) within the porous framework. The maximum specific hydrogen uptake values (total) for MIL-101 are 12.3 (at 81) and 7.2â wt. % (at 293â K). Such unique measurement conditions allowed us to identify the density of the absorbed hydrogen directly from the excess sorption isotherm curves. The corresponding density values were found to be almost comparable at low temperature, but significantly different at ambient temperature, which indicated an increase of more than double in the number of hydrogen binding sites in the case of the inclusion compounds with rhenium clusters.
RESUMEN
Using a volumetric technique, the deuterium solubility, X, in heavy water (L), low-pressure hexagonal ice (I h), and high-pressure cubic clathrate ice (sII) is studied at deuterium pressures up to 1.8 kbar and temperatures from -40 to +5 degrees C. The triple point of the L + I(h) + sII equilibrium is located at P = 1.07(3) kbar and T = -4.5(8) degrees C. The molar ratios D2/D2O of phases at the triple point are X(L) = 0.020(5), X(Ih) = 0.012(5), and X(sII) = 0.207(5).