Development of halogen‐free flame‐retardant thermoplastic elastomer polymer blend

Ethylene‐propylene diene rubber (EPDM) and isotactic polypropylene (iPP) blends have widest industrial applications that require a degree of flame retardancy. Halogen‐free intumescent technology based on phosphorous salt is a significantly advanced approach to make the polymer flame‐retardant. Both ammonium polyphosphate and ethylenediamine phosphate are important intumescent compounds. Their combination with carbonific and spumific agents were studied in binary blends of EPDM/PP. The polymer system was vulcanized online during melt mixing. Intumescent flame‐retardant polymer systems exhibit good flame‐retardancy with optimum comparable physiomechanical, electrical, and fluid resistance properties, including lower smoke emission, which is essential to protect people because the visibility remains unaffected in the event of fire. Pronounced charring and intumescent effect appear to enhance the flame‐retardancy of the polymers. Possible expected intumescent mechanism is proposed based on the nonpyrolysis mechanism for the flame‐retarded polymer and the intumescent components. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 407–415, 2004     

Effect of Ionic Liquids on Surface and Aggregation Properties of Non-ionic Surfactant Triton™ X-100 in Aqueous Media

The effect of the hydrophilic ionic liquids (ILs) 1-butyl-2,3-dimethylimidazolium bromide [bdmim][Br] and 1-hexyl-2,3-dimethylimidazolium bromide [hdmim][Br] on the aggregation and surface active behaviour of the non-ionic surfactant Triton? X-100 (TX-100) was studied in aqueous media. Several aggregation properties of TX-100 + IL/water systems, such as critical micelle concentration (CMC), surface active parameters, aggregation number (N _agg) and aggregate size, were determined by surface tension, fluorescence and dynamic light scattering (DLS) techniques. It was found that the average micellar size and aggregation number decrease, whereas the CMC increases with increasing concentration of ILs. Interestingly, the CMC value of TX-100 is reduced slightly below 0.5 wt% of both the ILs in the medium. At higher wt% of IL in the system the CMC increases. It was demonstrated that ILs [bdmim][Br] and [hdmim][Br] can be judiciously used at different wt% for modifying the physico-chemical properties of TX-100.     

Synthesis and Biological Evaluation of Ferrocenylquinoline as a Potential Antileishmanial Agent

The emergence of resistance against antileishmanial drugs in current use necessitates the search for new classes of antileishmanial compounds. Herein we report the design, synthesis, and evaluation of a novel ferrocenylquinoline for activity against Leishmania donovani. 7‐Chloro‐N‐[2‐(1H‐5‐ferrocenyl‐1,2,3‐triazol‐1‐yl)ethyl]quinolin‐4‐amine ( 1 ) was generated by coupling an iron(II) ethynylferrocene species with 4‐(2‐ethylazido)amino‐7‐chloroquinoline using click chemistry. The synthesized compound 1 was tested for its antileishmanial activity using both promastigote and amastigote stages of L. donovani. Compound 1 showed promising anti‐promastigote activity, with an IC₅₀ value of 15.26 μM and no cytotoxicity toward host splenocytes. From the battery of tests conducted in this study, it appears that this compound induces parasite death by promoting oxidative stress and depolarizing the mitochondrial membrane potential, thereby triggering apoptosis. These results suggest that ferrocenylquinoline 1 is a suitable lead for the development of new antileishmanial drugs.     

Lipoxygenase and Tocopherol Profiling of Soybean Genotypes Exposed to Electron Beam Irradiation

Electron beam (EB)-irradiation is increasingly being preferred to radioactive-based gamma irradiation in overcoming the constraints that affect the quality of food material. Soybean seeds of 3 soybean genotypes were exposed to 4 doses viz. 4.8, 9.2, 15.3 and 21.2 kGy of EB-irradiation and assessed for the changes in the contents of lipoxygenase isozymes and tocopherol isomers. Densitometry of protein profile revealed decreasing intensity of lipoxygenase with increasing EB dose. All the 3 lipoxygenase isozymes viz. lipoxygenase-1, -2 and -3 registered significant (P < 0.05) increasing reduction with increasing dose; though genotypic variation was noted for the magnitude of reduction at the same dose. Concomitantly, all the 3 genotypes exhibited significant (P < 0.05) decline in α-, γ- and δ-isomers of tocopherol. δ-Tocopherol was the most sensitive to EB-irradiation. EB dose, which caused minimum and maximum decline in total tocopherol content, was genotype-dependent. Decline in vitamin E activity corresponding to the dose, which induced maximum reduction for total lipoxygenase also varied in 3 genotypes. The study showed the usefulness of EB for significant inactivation of off-flavor generating lipoxygenases in soybean, with a non-significant effect on oil content and varied retention of tocopherol isomers and vitamin E activity depending upon genotype.     

Synthesis and Characterization of Poly(acrylic acid)/Poly(vinyl alcohol)-xanthan Gum Interpenetrating Network (IPN) Superabsorbent Polymeric Composites

Initially interpenetrating network (IPN) hydrogel was prepared by dispersing xanthan gum (XG) into poly(vinyl alcohol) (PVA) backbone in an aqueous medium. Polyacrylic acid (PAA)/Poly (vinyl alcohol)-Xanthan gum IPN superabsorbent composite were fabricated well by dispersing the prepared IPN hydrogel in acrylic acid and polymerized in a complete aqueous environment through chemical cross-linking method. These superabsorbent polymeric composites were analytically evaluated by scanning electron microscopy (SEM), Fourier Transform Infrared Spectra (FTIR), Thermal analysis (DSC) and X-ray diffraction (XRD) analysis. Simultaneously water absorbency, swelling kinetics and water retention abilities of this prepared superabsorbent polymeric composites were also investigated systematically.     

Heat Pump Drying of Green Sweet Pepper

Thin-layer drying experiments under controlled conditions were conducted for green sweet pepper in heat pump dryer at 30, 35, and 40°C and hot air dryer at 45°C with relative humidities ranging from 19 to 55%. The moisture content of sweet pepper slices reduced exponentially with drying time. As the temperature increased, the drying curve exhibited a steeper slope, thus exhibiting an increase in drying rate. Drying of green sweet pepper took place mainly under the falling-rate period. The Page equation was found to be better than the Lewis equation to describe the thin-layer drying of green sweet pepper with higher coefficient of determination and lower root mean square error. Drying in heat pump dryer at 40°C took less time with higher drying rate and specific moisture extraction rate as compared to hot air drying at 45°C due to lower relative humidity of the drying air in a heat pump dryer though the drying air temperature was less. The retention of total chlorophyll content and ascorbic acid content was observed to be more in heat pump–dried samples with higher rehydration ratios and sensory scores. The quality parameters showed a declining trend with increase in drying air temperature from 30 to 45°C. Keeping in view the energy consumption and quality attributes of dehydrated products, it is proposed to dry green sweet pepper at 35°C in heat pump dryer.     

Design,Synthesis, and Evaluation of WC5 Analogues as Inhibitors of Human Cytomegalovirus Immediate‐Early 2 Protein,a Promising Target for Anti‐HCMV Treatment

Although human cytomegalovirus (HCMV) infection is mostly asymptomatic for immunocompetent individuals, it remains a serious threat for those who are immunocompromised, in whom it is associated with various clinical manifestations. The therapeutic utility of the few available anti‐HCMV drugs is limited by several drawbacks, including cross‐resistance due to their common mechanism of action, i.e., inhibition of viral DNA polymerase. Therefore, compounds that target other essential viral events could overcome this problem. One example of this is the 6‐aminoquinolone WC5 , which acts by directly blocking the transactivation of essential viral Early genes by the Immediate‐Early 2 (IE2) protein. In this study, the quinolone scaffold of the lead compound WC5 was investigated in depth, defining more suitable substituents for each of the scaffold positions explored and identifying novel, potent and nontoxic compounds. Some compounds showed potent anti‐HCMV activity by interfering with IE2‐dependent viral E gene expression. Among them, naphthyridone 1 was also endowed with potent anti‐HIV activity in latently infected cells. Their antiviral profile along with their innovative mechanism of action make these anti‐HCMV quinolones a very promising class of compounds to be exploited for more effective antiviral therapeutic treatment.     

Optimization of the Length of Silicon Nanowires Prepared from MACE Method Using Gene Expression Programming and Genetic Algorithm

Silicon - Metal-assisted chemical etching (MACE) of silicon is used in this study to fabricate silicon nanowire arrays (SiNWs) of different length. This method was modeled using gene expression...     

Architectural View of Flexible Aliphatic –OH Group Coordinated Hemi-Directed Pb(II)-Salen Coordination Polymer: Synthesis,Crystal Structure,Spectroscopic Insights,Supramolecular Topographies,and DFT Perspective

Journal of Inorganic and Organometallic Polymers and Materials - We serendipitously designed one novel 1D hetero-binuclear Zn(II)-Pb(II) coordination polymer, namely...