Crosslinked chitosan membranes: characterization and study of dimethylhydrazine dehydration by pervaporation

Structural, Mechanical, and Transport Properties of Electron Beam-Irradiated Chitosan Membranes at Different Doses

Chitosan powder irradiated by electron beam at different doses, up to 250 kGy, was used to prepare membranes for drug release applications. The irradiation effect on the molecular weight of powder chitosan, the characteristics of the prepared membranes, and their transport of sulfamerazine sodium salt (SULF) were investigated. The effect of the addition of glutaraldehyde (GLA) as a crosslinking agent in the chitosan solution used for the preparation of the membranes was also studied. A decrease in the chitosan molecular weight with the increase in the irradiation dose was observed, while the membranes prepared with the irradiated chitosan at higher dose exhibited lower swelling. However, an opposite behavior was detected when the membranes were prepared with GLA-crosslinked chitosan. A GLA crosslinking agent reduced the crystallinity of the chitosan membranes and the swelling, whereas the water contact angle and SULF transport increased with the increase in the irradiation dose.

Comparative analysis of protective effects of curcumin, curcumin-β-cyclodextrin nanoparticle and nanoliposomal curcumin on unsymmetrical dimethyl hydrazine poisoning in mice

The aim of this study was to compare the protective effects of curcumin, curcumin-β-cyclodextrin nanoparticle curcumin (BCD-CUR) and nanoliposomal curcumin (NLC) on unsymmetrical dimethylhydrazine (UDMH) induced poison in mice. Curcumin, BCD-CUR, and NLC were prepared and their properties of zeta potential, particle size, encapsulation efficiency, and loading capacity were characterized. Eighty-eight male ICR mice on normal chow diet were randomly divided into 11 groups, and intraperitoneally injected with UDMH alone, or together with different doses of curcumin, BCD-CUR or NLC daily for up to 10 d. Enzyme activities of serum alanine transaminase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) were analyzed by fully-automatic analyzer and neurotransmitter levels were determined with high performance liquid chromatography (HPLC). 150 mg/kg curcumin treatment alone significantly reduced levels of serum ALT and LDH that were induced by UDMH and markedly increased level of γ-amino butyric acid (GABA) that were reduced by UDMH in the hippocampus. 150 mg/kg BCD-CUR not only decreased significantly the increase of ALT, LDH and glutamate (Glu) but also recovered levels of AST and GABA. 150 mg/kg NLC recovered profoundly levels of AST and GABA while decreased remarkably the UDMH induced increase of ALT, LDH, Glu and 5-hydroxytryptamine (5-HT). In addition, treatments with all tested doses of NLC significantly reduced the UMDH induced dopamine (DA), the monoamine neurotransmitter. NLC had more profound protective effects against liver and central nervous system injury induced by UDMH than a suspension of BCD-CUR or curcumin did in mice.

Pervaporation performance of PPO membranes in dehydration of highly hazardous mmh and udmh liquid propellants

Polyphenylene oxide (PPO) membranes synthesized from 2,6-dimethyl phenol monomer were subjected to pervaporation-based dehydration of the highly hazardous and hypergolic monomethyl hydrazine (MMH) and unsymmetrical dimethyl hydrazine (UDMH) liquid propellants. Membranes were characterized by TGA, DSC and SEM to study the effect of temperature besides morphologies of surface and cross-section of the films, respectively. Molecular dynamics (MD) simulation was used to study the diffusion behavior of solutions within the membrane. CFD method was employed to solve the governing mass transfer equations by considering the flux coupling. The modeling results were highlighted by the experimental data and were in good agreement. High separation factors (35-70) and reasonable water fluxes (0.1-0.2 kg/m(2)h) were observed for separation of the aqueous azeotropes of MMH (35 wt%) and UDMH (20 wt%) and their further enrichment to >90% purity. Effect of feed composition, membrane thickness and permeate pressure on separation performance of PPO membranes were investigated to determine optimum operating conditions.