Pramod P. Mahulikar

A selective and discriminating noncyclic receptor for HSO4− ion recognition

The anion recognition ability of a novel noncyclic dipodalamine phenol receptor L was evaluated using absorption and fluorescence spectroscopic methods. The absorption and fluorescence spectra of L have shown a red shift upon the addition of HSO4− over other surveyed anions in water. The association constant (Ka) of L with HSO4− was calculated using Benesi–Hildebrand plot and Scatchard plot methodology, and it was found to be 3.1 ± 0.2 × 103 M−1.

Fly‐Ash‐Supported Synthesis of 2‐Mercaptobenzothiazole Derivatives under Microwave Irradiation

Abstract Microwave‐assisted, solvent‐free alkylation and acylation of 2‐mercaptobenzothiazole has been attempted using silica gel, alumina, and a new solid support, fly ash. Fly ash, a waste generated at thermal power stations, could be used as solid support just as efficiently as commercial supports. The additional features of methodology include a much faster reaction, easy workup, higher yields, higher purity of the products, and an ecofriendly approach.

Studies on electrochemical, optical and electrical conductivity characteristics of copolymer of polyaniline-co-poly(o-toluidine) using various organic salts

An attempt has been made to prepare polyaniline (PA), poly(o-toluidine) (POT) and their copolymer polyaniline-co-poly(otoluidine) (PA–POT) thin films doped by several organic salts with varying size of cation, using aqueous solution of H2SO4 as electrolyte. Effect of dopant in the presence of electrolyte is rarely studied in the field of conducting polymers. Various organic salts as dopants, viz. potassium acetate, sodium acetate and magnesium acetate were used at room temperature. The films were electropolymerized in solution containing 0.1 M monomer(s), 1 M H2SO4 as electrolyte and 1 M organic salt by applying sequential linear potential scan rate 50 mV/s between 0.2 and 1.0 V versus Ag/AgCl electrode. The electro-synthesized films were characterized by cyclic voltammetry, UV–Visible spectroscopy and conductivity measurements. The UV–Visible spectra were obtained ex situ in dimethyl sulfoxide (DMSO) and peaks are observed to appear at about 800–810 nm with a shoulder at 410–420 nm are for emeraldine salt (ES) phase of PA, POT, PA–POT without any doping salt. In the presence of salts, a shift for these absorptions was observed to lower wavelength (758–786 nm), however, a shift of shoulder to higher wavelength (413–425 nm). In overall study, an increase in conductivity was observed for all aforesaid dopants and among these, potassium acetate was found to be the best. D 2003 Elsevier Science B.V. All rights reserved.

Controlled Release Study of Phenol Formaldehyde Microcapsules Containing Neem Oil as an Insecticide

Many of the biological pesticides are supposed to be more effective than synthetic ones in controlling pests. In this communication, we report a successful encapsulation of neem oil, one of the most effective biological insecticides, in phenol formaldehyde microcapsules. This was achieved by adopting an in-situ polymerization process in oil-in-water emulsion. The synthesis consists of two parts, namely emulsification of the oil and wall formation. The synthesized microcapsules were characterized by FTIR, SEM, TGA, and particle size analyzer. The controlled release was monitored by measuring optical observation in the UV range.

Conducting polymers: an emerging field of biosensors

Conducting polymers have attracted much interest in the development of biosensors. Electrically conducting polymers are known to possess numerous features, which allow them to act as excellent materials for immobilization of biomolecules and rapid electron transfer for the fabrication of efficient biosensors. The present review describes the salient features of conducting polymers as biosensors, their construction, working, importance and applications.

Effect of Nano–Magnesium Hydroxide on Mechanical and Flame-Retarding Properties of SBR and PBR: A Comparative Study

Magnesium hydroxide [Mg(OH)2] is one of the potential inorganic fillers. In this work, nanoparticles (37±5 nm) of the magnesium hydroxide were prepared using matrix-mediated growth and control technique, and their size was confirmed by X-ray diffraction technique. Nano-Mg(OH)2-SBR and nano-Mg(OH)2-PBR composites with 2–10% (w/w) filler loading were prepared by compounding on laboratory-scale two-roll mill and a compression molding machine. These composites were tested for tensile and physical properties, and the properties were compared with the composites of commercial Mg(OH)2. The incorporation of nanofiller improved the properties of nanocomposites.

The Amidine Based Colorimetric Sensor for Fe 3+ , Fe 2+ , and Cu 2+ in Aqueous Medium

An amidine based chemosensor AM-1 was synthesized and characterized by various spectroscopic (FT-IR, 1H-NMR and mass) data and elemental analyses. Sensor AM-1 exhibited high selectivity and sensitivity towards Fe3+, Fe2+ and Cu2+ in the presence of other surveyed ions (such as Sr2+, Cr3+, Co2+, Ni2+, Zn2+, Ag+, Al3+, Ba2+, Ca2+, Cd2+, Cs+, Hg2+, K+, Li+, Mg2+, Mn2+, Na+ and Pb2+) with a distinct naked-eye detectable color change and a shift in the absorption band. Moreover, the emission of AM-1 was quenched selectively only in the presence of Fe3+.

Electrochemical synthesis of poly(o-anisidine), poly(o-toludine) and their copolymers in organic sulphonic acid

The effect of organic sulphonic acids on electrochemical, optical and conductivity properties of poly( o -anisidine) (POA), poly( o -toluidine) (POT) and poly(o-anisidine-co-o-toluidine) (POA-co-POT) thin films has been investigated. The films were synthesized electrochemically, individual as homopolymers and then combined as (binary copolymer) under cyclic voltammetric conditions in an aqueous solution of sulphuric acid, p-toluene sulphonic acid, sulphamic acid and sulphosalicylic acid at room temperature. The films were electropolymerized in solution containing 0.1 M monomers and respective electrolyte (1 M sulphuric acid or organic sulphonic acid) by applying sequential linear potential scan rate of 50 mV/s between-0.2 and 1.0 V versus Ag/AgCl electrode. The electrosynthesized films were characterized by cyclic voltammetry, UV-Vis spectroscopy and conductivity measurement. It is observed that the UV-Vis peaks for sulphuric acid, p-toluene sulphonic acid, sulphamic acid and sulphosalicylic acid appear in the region of the conducting emeraldine salt (ES) phase. Overall, the polymers prepared using all these three organic sulphonic acids have higher conductivity than sulphuric acid; however, the higher conductivity is observed for p-toluene sulphonic acid as electrolyte in comparison with sulphamic acid and sulphosalicylic acid. The formation of copolymer (POA-co-POT) has been supported and confirmed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) studies. A possible scheme of reaction mechanism for homo- and copolymer has been suggested.

Development of anticorrosive two pack polyurethane coatings based on modified fatty amide of Azadirachta indica Juss oil cured at room temperature – a sustainable resource

We report the modification of Azadirachta indica Juss oil (renewable source) fatty amide by the piperazine molecule to develop a new polyol. Two pack polyurethane (PU) coatings on mild steel plates were prepared by reacting newly developed polyol with toluene diisocyanate (TDI) at room temperature. Spectral studies of Azadirachta indica Juss oil based fatty amide and piperazine modified fatty amide were carried out using spectroscopic techniques to confirm the modification. The prepared resins were also characterized by end group analysis such as amine and hydroxyl values. Anticorrosive properties of the prepared PU coatings were examined by immersion test in an aqueous salt solution. The thermal stability of coatings was studied by TGA. Other coating properties such as gloss, scratch hardness, adhesion, flexibility, impact resistance and chemical resistance were evaluated using standard methods. It was observed that the presence of nitrogen containing piperazine moiety in the back bone of the PU chain shows better anticorrosive properties compared with the Azadirachta indica Juss oil fatty amide based PU coatings.

Fabrication of dendritic 0 G PAMAM-based novel polyurea microcapsules for encapsulation of herbicide and release rate from polymer shell in different environment

New sequence of microcapsules with dendritic PAMAM-based novel polyurea as shell wall material containing herbicide as a core moiety has been prepared by interfacial polymerization technique. Dendrimer-based polymeric microcapsules were fabricated with aim to study the effect of different reaction parameters such as surfactant dose, core loading, agitation speed, and amount of solvent on particle size, particle size distribution, and appearance of microcapsules. Prepared microcapsules were characterized by FTIR, thermo gravimetric analysis, particle size analysis, scanning electron microscope, and other microscopic technique. In present investigation, surfactant dose of 2.5% with 5 mL of solvent at 400 rpm was found to be optimum for fabrication of stable new polyurea microcapsules containing 1 g of core. The synthesized microcapsules with optimized parameters were evaluated quantitatively for controlled release study by gas chromatography in different environmental conditions. The highest percent release of core was found in acidic conditions compared to that of basic and least in neutral medium.