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Aim: The aim of the study was to design and develop a greener, efficient protocol towards newer pyridinium and imidazolium compounds, and investigate optical, solvatochromic, thermal, and theoretical properties. Background: Pyridinium and imidazolium based compounds show diverse application compounds with these basic skeleton designs in respect to get improved optical and thermal behavior. Objectives: The purpose is to study the optical properties of pyridinium and imidazolium compounds, for which we illustrate the solvent polarity effect on the absorption and emission behavior as a function of orientation polarizability and ET(30) solvent parameters. The study focuses on thermal stability and computes the molecular orbital orientation and HOMO- LUMO energies using theoretical simulation by the DFT approach. Methods: The structures were confirmed by FT-IR, Mass, 1H NMR and 13C NMR, and optical properties were investigated using a UV-Visible spectrophotometer and fluorometer. The thermal behavior was investigated using thermal gravimetric analysis, and molecular orbital orientation and energies were determined using GAUSSIAN 16 software. Results: The newer compounds with good thermal stability and optical behavior have been synthesized and characterized. The study interprets the intermolecular electron transfer amongst the molecules and the effect of solvents on their excitation and emission properties. The experimental and theoretical study illustrates the optical, thermal, and electronic properties of both compounds. Conclusion: The present work describes the solvatochromic optical behavior of pyridinium bromide and imidazolium bromide synthesized by a microwave-assisted, greener and efficient strategy. The solvatochromic study interprets the presence of non-specific solutesolvent interactions. The photophysical, thermal, and DFT study revealed that both pyridinium and imidazolium compounds are used for optoelectronic applications. Moreover, the work could be helpful to researchers for developing new skeletons for optoelectronic applications.

Newer imidazolium bromide compound was prepared by reacting 1-methyl imidazole and 2-bromo-1-(naphthalen-2- yl)ethanone under microwave irradiation. The structure of the imidazolium compound was confirmed by spectral analysis, further photophysical, solvatochromic, and thermal properties were investigated. The Lippert-Mataga plot and solvent polarity empirical parameter ET(30) were used to examine solvent dependent optical properties of imidazolium compounds with a range of solvents with varying polarities. The thermal stability and phase behavior were studied by TGA and DSC analysis with a heating rate of 10 deg min-1 . DFT computation was performed to get the optimized molecular orbitals and HOMO - LUMO energies.

The nanofiller improve the properties of the pristine polymer resins to the great extent. In present findings, the preparation of nanocomposites (epoxy/PNCC/LDHs) was done by the ‘Slurry-compoundin...

Present study investigates, the synergistic effect of Precipitated Nano Calcium Carbonate with Layered Double Hydroxides (LDHs) on thermal and mechanical properties of unsaturated polyester resin. ...

Herein we report a simple and convenient, base promoted synthetic method for preparation of (Z)-2-(2-phenyl-4H-benzo[4,5]thiazolo[3,2-a]pyrimidin-4-ylidene)acetonitrile derivatives. The reactions involve ring transformation of 2H-pyran-3-carbonitriles 1 with 2-aminobenzthazole 2 using Cs2CO3 at room temperature. Absorption and emission properties of synthesized compounds were investigated in solvents of varying polarity. It was found that for all studied compounds no distinguishable behaviour was observed for absorption in different solvents whereas some notable changes were observed in emission fluorescence spectras. Solvent dependent spectral properties of compounds were investigated using Lippert-Mataga plot. A rational relationship is examined between fluorescence quantum efficiencies and calculated HOMO energies.

The development of novel energetic materials with highest possible performance is of current interest. Synthesis of such materials is performed at various stages of pilot plant production all over the world. However, their synthesis involves hazardous production processes. This paper discusses relatively safe and eco-friendly approaches and techniques such as microwave technology and the use of ionic liquids for the synthesis of high-performance energetic materials that can be used as explosives and propellants. In addition, the use of dinitrogen pentoxide as an efficient nitrating agent for the synthesis of energetic materials is considered.

The electrochemical reduction of thymine (T) and thymidine (Thy) in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid at room temperature is investigated using cyclic voltammetry (CV). The CV of thymine shows one-electron reduction peak at − 0.67 V vs Fc/Fc+, while thymidine exhibited two reduction peaks corresponding to − 1.54 V and at − 2.06 V vs Fc/Fc+. The difference in the reduction peaks of thymine and thymidine observed suggests a single-step and two-step reductions, respectively. The experimental voltammogram was convoluted for the the estimation of diffusion coefficient, charge transfer coefficient, kinetics, and energetics of thymine and thymidine. The theoretical prediction using semi-integral technique suggests that thymidine at the reduction peak − 1.54 V vs Fc/Fc+ proceeds a one-electron reductive cleavage of N–C glycosidic bond (nitrogen–carbon) via concerted dissociative electron-transfer mechanism while thymine.

A new series of 5-(1-benzyl-1H-1,2,3-triazol-4-yl)-4-methyl-2-arylthiazole derivatives, 6a−w have been synthesized by click reaction of substituted benzylazide, 5a−d with 5-ethynyl-4-methyl-2-substituted phenylthiazole, 4a−f. The starting compounds 4-ethynyl-2-substituted phenylthiazole (4a−f) were synthesized from the corresponding thiazole aldehyde by using the Ohira−Bestmann reagent. The structure of the synthesized compounds was determined by spectral analysis. All the synthesized compounds were screened for their preliminary antitubercular activity against Mycobacterium tuberculosis H37Ra (MTB, ATCC 25177). Most of the synthesized compounds reported good activity against M. tuberculosis H37Ra strain with IC50 range of 0.58−8.23 µg/mL. Compounds 6g and 6k reported good antitubercular activity with MIC90 values of 4.71 and 2.22 µg/mL, respectively. Potential antimycobacterial activity suggested that these compounds could serve as good lead compounds for further optimization and development of a newer antitubercular candidate.

Citric acid was discovered as an efficient catalyst for the rapid synthesis of pharmacologically important isoniazid azomethines by condensation of aromatic aldehydes and isatins with isoniazid in aqueous ethanol under reflux condition. The advantages of the described method include the use of readily available starting materials, biodegradable greener catalyst, and mild reaction conditions. The products were obtained in high yield within short reaction time and no need for column chromatography purification.

The vegetable oil-based waterborne polyurethane coatings have gained significant interest due to low volatile organic compounds, and hence, this has been considered as a proper substitute to the commonly used solvent-borne coating systems. In the present work, we have developed the polyurethane coatings from diethanolamide of fatty acid and dicarboxylic acid (sebacic acid and succinic anhydride)-based poly(esteramide) resin as a diol along with 2,2′-dimethylol propionic acid and isophorone diisocyanate. The chemical structure of bio-based diol and PU coatings was elucidated by FTIR and 1H NMR spectroscopy. The polyurethane dispersions (PUDs) prepared were analysed by particle size analysis and stability. The mahua oil-based PUDs were coated on the metal panels and the cured material obtained was characterized by the physico-mechanical, chemical resistance and the thermal properties which were compared with the petroleum resource-based PUDs. The PUD coatings showed good physico-mechanical properties, chemical resistance and thermal stability. Hence, the dispersion prepared from bio-based diols may find application as eco-friendly coatings.

A one-pot, multi-component, synthetic method for preparation of 2-amino-4-substituted-1,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitriles has been developed. It was accomplished by mixing 2-aminobenzimidazole, aldehyde and malononitrile in the presence of S-Chit-HAp@Fe3O4 as a nanocatalyst in aqueous medium. The catalyst (S-Chit-HAp@Fe3O4) was synthesized using a co-precipitation method and further characterized by using FT-IR, XRD, FE-SEM, EDX, HR-TEM, TGA and VSM analysis. It was found that the catalyst exhibits magnetic properties and showed high catalytical activity for the synthesis of 2-amino-4-substituted-1,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitriles. S-Chit-HAp@Fe3O4 nanoparticles catalyzing one-pot, multi-component synthesis of 2-amino-4-substituted-1,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitriles in aqueous medium has been reported herein.

Synthetic self-healing materials are a new prototype in polymeric coatings. In the present investigation, soybean oil along with drier was encapsulated in urea–formaldehyde (UF) microcapsules, which were successfully prepared by in situ polymerization and their self-healing ability, the corrosion resistance, gloss, and adhesion strength of microcapsules were studied. The synthesized microcapsules were characterized by Fourier transform infrared spectrometer for identification of separated core and shell materials and their surface morphology was studied by scanning electron microscope. The particle size was checked under optical microscope and confirmed with particle size analyzer. Effectiveness of soybean oil-filled microcapsules was investigated for healing of cracks generated in anticorrosive coatings. Cracks in paint coatings were found to be healed when soybean oil was released from microcapsules under simulated mechanical action and the corrosion resistance of healed area was evaluated by im...

A series of 2-aryl-4-((4-aryl-1H-1,2,3-triazol-1-yl)methyl)thiazole derivatives (8a–p) have been synthesized. The structure of the newly synthesized compounds was determined by spectral analysis. The title compounds were screened for their preliminary antitubercular activity against Mycobacterium tuberculosis H37Ra (MTB, ATCC 25177) and Mycobacterium bovis BCG (BCG, ATCC 35743). Further, the synthesized compounds were screened for antimicrobial activity against standard Gram-negative bacteria Escherichia coli (NCIM 2576) and Pseudomonas flurescence (NCIM 2059) and Gram-positive bacteria Staphylococcus aureus (NCIM 2602) and Bacillus subtilis (NCIM 2162). Among all the synthesized compounds, 8a–c, f–h, m exhibited good activity against dormant M. bovis BCG strain. Compounds 8h, j exhibited good activity against all tested bacterial strains. All active compounds were screened for cytotoxicity and found inactive. Their high potency and promising antimycobacterial activity suggest that these compounds could serve as good leads for further optimization and development.

The poly{[p-(azidomethyl)styrene]-co-(5-vinyltetrazole)} was successfully synthesized by azidation of a copolymer, such as poly-{[p-(chloromethyl)styrene]-co-acrylonitrile} under microwave irradiation. This method was very simple, rapid, and carried out in a controllable way. In this greener approach, the chlorine atom of the copolymer was easily replaced by azide group, and the cyanide group was converted to tetrazole moiety under microwave irradiation. The synthesized copolymers were characterized by spectral analysis, and their thermal properties were estimated using thermogravimetric analysis and differential scanning calorimetry.

Energetic polymers containing nitro, nitrato, and azido groups release high energy during combustion and thereby increase the performance of the systems. A number of energetic polymers have been found suitable for use as binders in high-performance propellant and explosive formulations. This review describes the synthetic and application aspects of various modern energetic polymers for explosive formulations and propellants.

Bio-based thermoset polyurethane (PU) coatings comprised of polyesteramides were prepared from Gossypium arboreum (cotton seed) plant oil as a renewable source. Oil was first converted into fatty amide that was transformed into a series of polyesteramide polyols upon esterification with different dicarboxylic acids and anhydride. In the preparation of polyesteramide polyols, to increase bio-based content five different dicarboxylic acids of renewable nature were used to replace petroleum counterparts. Structures of polyols were confirmed using NMR and FT-IR spectroscopic techniques. Molecular weights of polyols were determined using gel permeation chromatography. Bio-based polyesteramide polyols were used to prepare thermoset PU by treating with aromatic diisocyanate. The thermal behavior of all prepared polyurethane coatings was determined using a thermogravimetric analyzer and differential scanning calorimeter. Coatings prepared using renewable source based polyesteramides were with high suitable curing, mechanical/chemical performances, alkali/acid resistance, and hydrophobicity. Compared to conventional PU coatings, the prepared coatings possess the superior properties such as gloss, adhesion, and pencil hardness. Thus present work demonstrates Gossypium arboreum plant oil and dicarboxylic acids as newer eco-friendly raw materials for PU coatings and compared with standard petro based polyols.

Silver nanoparticles (AgNPs) were prepared and tested for the activity in the catalytic reduction of 4-nitrophenol to 4-aminophenol showing to be exceptionally active. Further, using AgNPs we catalytically synthesized 1-(4-isobutylphenyl)ethanol which is important drug intermediate for the widely used Ibuprofen. The rate constants were determined at temperatures 298 K, 303 K, 308 K, 313 K, 318 K, 232 K correspond to 0.29 min−1, 0.37 min−1, 0.40 min−1, 0.43 min−1, 0.50 min−1, 0.68 min−1, respectively. The activation energy of AgNPs is 23.25 kJ/mol. The number of collisions of reactants in the term of frequency factor was found to be high 1.99 × 108 min−1 and average heat of reaction is 26.1 kJ/mol. The recyclability study of AgNPs in the reduction of 1-(4-isobutylphenyl)ethanone (4-IBPEON) to 1-(4-isobutylphenyl)ethanol (4-IBPE) in six consecutive reaction cycles found to be (0.91 g, 90%), (0.89 g, 88%), (0.87 g, 86%), (0.84 g, 83%), (0.84 g, 83%), (0.81 g, 80%), respectively. We promisingly minimize the waste generated in the synthesis of 4-IBPE by calculation E-factor and atom efficiency and was found to 0.57 and 81.56%, respectively. Reported experimental results were directly relevance to develop theoretical concepts.

Newer, simple and efficient synthesis of 2-((5-methoxynaphthalen-1-yl)methyl)-3-methyl-5-sec-amino-[1,1′-biphenyl]-4-carbonitrile derivatives using ring transformation strategy. The synthesized products were characterized by spectral analysis, fluorescence emission and absorption measurements were studied in various solvents having varying polarity and dielectric constants to find out a change in dipole moment in ground state and excited state of derivatives. Lippert–Mataga plots were utilized to know the effect of solvent polarity on spectral behavior of molecules. The position of the Stokes shifts was found to be depends on specific solute–solvent interactions, playing a vital role in electronic excitation of molecules. A rational relationship is examined between fluorescence quantum efficiencies and calculated HOMO and LUMO energies by DFT calculations. The electrochemical investigation of derivatives was performed by cyclic voltammetry.

Algae are a group of photosynthetic marine or freshwater plants that exhibit high CO2 capturing capacity. Algae have been among the most promising renewable resources for overcoming climate change issues. In this study, algae oil (AO) was chemically transformed to polyols through two-step reactions and incorporated into value-added and industrially important polyurethane (PU) coatings. First, AO was reacted with diethanolamine to afford fatty amide. Then, polyetheramide polyols (AEAs) were prepared by reacting the fatty amide with bisphenol-A, 1,4-butanediol, or isosorbide. PU coatings were prepared by reaction between the AEAs and diphenylmethane diisocyanate. The PUs exhibited typical semicrystalline and three-step degradation behaviors with enhanced gel content values, supporting the high reactivity of the AEAs as polyols. The hydrophobic characteristics of the fatty acid chains of the AEAs resulted in decreased water absorption of the PUs, which improved the antimicrobial characteristics of the PUs. In particular, the PU coatings exhibited excellent resistance against alkaline aqueous media and organic solvent (xylene) along with reasonable gloss, hardness, flexibility. In saline aqueous media, the PU coatings exhibited anticorrosion performance superior to that of typical poly(tetramethylene ether) glycol-based PU coating. This study demonstrates the high potential of the PUs as anticorrosion and antimicrobial materials from the environmentally friendly renewable resource.

The present study reports a process wherein CO2 is captured in the form of bicarbonates using calcium oxide and photosynthetically fixed into biomass. Microalgal cultures viz. Chlorella sorokiniana PAZ and Arthrospira sp. VSJ were grown in the medium containing bicarbonates. The rate of bicarbonate utilization by C. sorokiniana PAZ was higher when CO2 trapped in the presence of 2.67mM calcium oxide than in the presence of 10mM sodium hydroxide and with direct addition of 10mM sodium bicarbonate. For Arthrospira sp. VSJ the bicarbonate utilization was 92.37%, 88.34% and 59.23% for the medium containing CaO, NaOH and NaHCO3, respectively. Illumination of photosynthetically active radiation (PAR)+ultraviolet A radiation (UVA) enhanced the yield of C. sorokiniana PAZ and Arthrospira sp. VSJ by 1.3 and 1.8 folds, respectively. FTIR analysis revealed elevation in the biosynthesis of specific metabolites in response to the UVA exposure.

One-pot multicomponent synthesis of benzimidazoquinazolinone scaffolds was achieved by reaction between 2-aminobenzimidazole, aldehyde, and 1,3-cyclohexadione in choline chloride:glycerol as deep eutectic solvent (DES). The developed methodology offers mild and faster reaction conditions with excellent product yield. The synthesized compounds were screened for their antioxidant potency using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power (FRAP), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and metal chelating assay. Most of the compounds were found to exhibit good to comparable antioxidant activity with respect to standards. Use of this inexpensive and biodegradable solvent makes this methodology a greener approach compared with other methods reported in literature. Greener, one-pot multicomponent synthesis of benzimidazoquinazolinone scaffolds using DES (ChCl:glycerol) as efficient, recyclable, and biodegradable solvent has been achieved. The synthesized compounds show good to comparable antioxidant activity compared with standards.

The poly(glycidylazide-co-terahydrofuran) [poly(GA-THF)] or GA-THF copolymers are recognized and established as high-energy binders in explosive systems. In present study, we have developed a greener approach for the syntheses of poly(glycidylazide-co-tetrahydrofuran) copolymers using microwave (MW) irradiation technique. Polymerization of epichlorohydrin and tetrahydrofuran was carried out in the presence of borontrifluoride etherate and ethylene glycol to afford polyepichlorohydrin-tetrahydrofuran (PECH-THF) copolymer followed by its reaction with sodium azide in DMF under microwave irradiation to give poly(GA-THF). The poly(GA-THF) copolymer and their precursors were characterized by various spectral techniques such as MS, 1H-NMR, 13C-NMR, UV–visible, and FTIR. The thermal analysis was done by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Molecular weights of these copolymers were determined using GPC techniques. Morphology of these copolymers was visualized using SEM. Our experimental study shows that the microwave irradiation was effective for the second step (azidation reaction) than conventional heating for the synthesis of GA-THF copolymers. Also, the benign syntheses were tackled and explored with range of solvents. Thus, the current methodology, might advent the researchers dealing with these high-energy binder materials in future.

Fluorescent siderophore pyoverdin (PVD) was produced from a soil isolate Pseudomonas monteilii strain MKP 213. The PVD was purified near to homogeneity and applied for the fluorescent chemosensing of various antibiotics in aqueous solution (pH=7.0). Upon addition of ciprofloxacin, PVD showed new UV-vis absorption bands at 252 and 321nm due to an internal charge transfer mechanism. Also, the addition of ciprofloxacin induced a highly selective fluorescence enhancement of PVD with a 13nm blue shift from 458 to 445nm. The combination of a long peptide chain along with the chromophore unit of PVD generates a converging cleft for ciprofloxacin recognition with LOD and LOQ of 7.13μM and 21.6μM, respectively without interference from other studied antibiotics. The association constant (Ka) of PVD with ciprofloxacin was calculated to be as low as 1.40×10(5)M(-1) using Benesi-Hildebrand plot depicting its significance in detection. The pharmaceutical tablet analysis measures the sensing with negligible matrix effect and quantitative recovery.

4,10-Dinitro-2,6,8,12-tetraoxa-4,10-diazaisowurtzitane (TEX), a well-known nitramine category explosive, is much less sensitive to impact and friction stimuli as compared to the familiar explosives, RDX and HMX. TEX is currently produced on pilot plant scale and is being pursued as an insensitive explosive. Herein a newer, improved, efficient, and high yielding protocol is developed for the synthesis of TEX by using solid acidic silica sulfuric acid as an efficient and recyclable catalyst. Sequentially for process parameters optimization, a study was carried out with variation of catalyst loading, nitric acid, and mole ratio of reactants. The process scale-up is also achieved successfully.

A novel method for the fabrication of robust polyurea microcapsules containing tung oil as a core material was developed for self-healing anticorrosive coating application. Well-distinct microcapsules with polyurea as a shell were prepared by reacting hexamethylene diisocyanate trimer with 0.0 G polyamidoamine (PAMAM) via interfacial polymerization technique. Fourier transform infrared spectroscopic analysis was performed to elucidate the chemical structure of microcapsules as well as to confirm successful encapsulation of core by the polyurea shell. Surface morphology, particle size, distribution of particle size, thermal, and mechanical properties of the prepared PAMAM-based polyurea microcapsules were compared with microcapsules that were prepared using diethylenetriamine (DETA) and triethylenetetramine (TETA). The prepared microcapsules were embedded with acrylic polyol-based polyurethane (PU) coatings to ensure anticorrosive performance. The immersion study of self-healing PU coatings loaded with 5% PAMAM-based polyurea microcapsules possesses satisfactory anticorrosive property under an accelerated corrosion process in 5% NaCl salt solution.

A simple, efficient and environmentally benign protocol has been developed for the synthesis of substituted benzo[4,5]imidazo[1,2-a]chromeno[4,3-d]pyrimidin-6-one by a reaction of 4-hydroxycoumarin, aldehydes and 2-aminobenzimidazole using silane@TiO2 nanoparticles as heterogeneous catalyst under reflux condition in ethanol. The surface modification of TiO2 nanoparticles was confirmed by using FT-IR, FE-SEM, EDX, XRD and TEM analyses. Furthermore, the stability of the catalyst was evaluated by thermal gravimetric analysis (TGA). Some advantages of this method are high yield of products, short reaction time; recyclability of the catalyst and column chromatography-free protocol. The synthesized compounds were screened for their in vitro antioxidant activity and most of the compounds exhibited remarkable antioxidant activity.

This work focused on two difficulties associated with preparation of polypropylene/wood flour (PP/WF) composites, viz. the compatibility of PP with WF and processing of the composites with high melt viscosity. Maleic anhydride-grafted polypropylene (MAPP) was used in the preparation of PP composites to provide the compatibility between polymer and filler. Hyperbranched polyester (HBPE) was incorporated to check feasibility of it as a processing aid in the same. The PP/WF composites were formulated by melt compounding on a Brabender Plastograph EC. Blending effect of compatibilizer and processing aid HBPE on PP/WF biocomposites have been carried out on the basis of torque analysis, mechanical properties, morphology, and thermal stability. The investigation showed that HBPE improves the processibility of PP/WF composites than MAPP with respective to torque value. The mechanical and thermal properties slightly vary with change in relative proportion of MAPP and HBPE. J. VINYL ADDIT. TECHNOL., 2016. © 2016 Society of Plastics Engineers

A series of bio-based polyester polyols with hydroxyl chain end was prepared using eugenol as a renewable source and various renewable diacids such as dimer, sebacic, succinic, and maleic acids. The functional group transformations and structure of monomer and polyols were analysed by the spectroscopic techniques. The hydroxyl functional polyester polyols were reacted with methylene diphenyl diisocyanate (MDI) to obtain polyurethane (PU) coatings. The prepared PUs were used as anticorrosive coatings and their performance was checked by dipping and electrochemical methods against 3.5 % sodium chloride (NaCl) solution. The developed coatings revealed excellent physico-mechanical properties such as transparency, gloss, flexibility, and cross-cut adhesion. Surface morphology and thermal stability of PU coatings were examined under scanning electron microscopy (SEM), atomic force microscopy (AFM), and thermogravimetric analysis, respectively.

Azomethine is the key linkage in all Schiff base reactions. The present context has efficiently emphasized on the utilization of Schiff base strategy effectively in the synthesis of polyazomethine polymer gel materials. The synthesized polymer gel is characterized by different physical techniques for testing its proper existence such as FESEM analysis, thermal gravimetric analysis, differential scanning calorimeter analysis, FTIR analysis and electron dispersive X-ray scattering analysis. The morphological study has revealed that the material is having 3D lamellar-layered architecture, i.e., layer-by-layer array of polymer chains. The synthesis governs several advantages, such as executing without using any catalyst and water as a green solvent. The present study also checked its complexion ability with nitro aromatic acceptors. The intercalation of nitro aromatic molecule between the two straight chains of the polymer gel is the beautiful peculiarity of these red-coloured complexes.

In this article, we represent preparation of renewable source based smart polyurethane coatings reacting polyols prepared by acetylation of neem oil with different diisocyanates in presence of encapsulated corrosion inhibitor. The structures of polyols were confirmed by Fourier transfer infra-red and nuclear magnetic resonance spectroscopic techniques. The prepared polyols were used to form polyurethane coatings by treating with diisocyanates such as methylene phenyl, dicyclohexylmethane, and isophorone diisocyanates. Further, conversion of polyurethane to smart coatings was carried by incorporation of encapsulated form of quinoline as a corrosion inhibitor. Coatings were characterized for their thermal stability and physico-chemical properties by suitable sophisticated techniques. Anticorrosive properties of the smart coatings were studied by exposing them to corrosive medias like 0.5 M HCl and 3.5% NaCl solutions. Incorporation of encapsulated corrosion inhibitor into the neem oil based smart PU coatings shown enhanced anticorrosive property. Finding of this study also shown encapsulated form of commercial corrosion inhibitor can be extended for other PU coatings.

Present paper reports coconut fatty acid-sucrose ester mediated coprecipitation synthesis of lead chromate nanocrystals with monoclinic symmetry in the size range of 18–48 nm. Solution spray reactor used for conducting the reactive crystallisation provides falling film mode of contact between atomised reactants. The adsorption density, surface functional groups, lattice parameters, size, morphology and optical properties of the PbCrO4 nanorods were determined by their surface tension, FTIR, XRD, FESEM-EDX and UV–vis analysis, respectively. The concentration and thus surface-active properties of sucrose ester were found to influence the crystallographic parameters, aspect ratio and UV–vis absorption properties of PbCrO4 nanocrystals. The nucleation parameters—induction time and energy barrier were reduced by 72% with increase in surfactant loading from 2 to 10 g/L for given initial supersaturation—200,000 and reaction temperature—303 K. The inter-multilayer and -micelle reactant exchange mechanisms were proposed and established to interpret the role of surfactant aggregation in enforcing the size stabilization, phase uniformity and polymorph selectivity in reference to kinetics and thermodynamics of precipitation of PbCrO4. The investigations are expected to fulfill the growing demand of developing appropriate theoretical principles and modelling methodologies in relation to the rationale control of size, polydispersity and structure of nanopigments.

A series of new polyester polyols has been synthesized by the condensation reaction of epoxidized vegetable oil and poly(ethylene glycol) (PEG). Vegetable oils obtained from natural resources namely, karanja ( Pongamia glabra ) and cottonseed ( Gossypium arboreum ) were epoxidized by an eco-friendly process and further used for the preparation of polyols using PEG. The molecular weight of PEG was varied from 200 to 600 g/mol. The polyester polyols obtained were characterized by end group and spectral analysis. Eco-friendly polyurethane coatings were obtained from the synthesized polyester polyols using dipentene, a green solvent instead of xylene as a conventionally used solvent. The resultant polyurethanes were characterized by different physicochemical and thermal properties. The coating properties namely, gloss, hardness, impact resistance, adhesion, and flexibility were also evaluated and found to be useful for industrial coatings.

In the present letter, an efficient, clean and one-pot synthesis of 2-substituted benzimidazole and 1,2-disubstituted benzimidazole derivatives has been explored by reacting o -phenylenediamine with aromatic aldehydes using bismuth nitrate as a catalyst in ethanol at ambient temperature. This methodology avails with faster reactions, excellent yield, mild reaction conditions, use of inexpensive and non-toxic catalyst compared to literature reported hitherto.

The use of reservoirs containing corrosion inhibitors as active substances for corrosion protection is an issue of great interest in the scientific literature. The aim of the present study is to encapsulate quinoline, a corrosion inhibitor, into a micro-reservoir to overcome disadvantages caused by its direct addition into a coating layer. Quinoline incorporated microcapsules with different core solvents were synthesized at room temperature by an interfacial polymerization method. The morphologies, wall structures, particle size and thermal properties of the synthesized microcapsules were investigated. The release study of core material was carried out by loss on drying and UV spectrophotometric methods. The prepared quinoline based microcapsules were incorporated in polyurethane (PU) coatings to study their effect on corrosion of substrate. The anticorrosive performance of coatings loaded with different weight % of microcapsules containing quinoline was tested by immersion of the PU coated mild steel specimens in 5 wt% HCl solution by visual observation and weight loss measurements.

This work deals with the preparation of alkyd resins from neem oil and their utilization in preparation of polyurethane coatings. Alkyd resins were synthesized by reaction of neem oil monoglycerides with four different divalent acids like phthalic anhydride, maleic anhydride, itaconic acid, and dimer fatty acid. The alkyds formation was studied by determining the acid number of the reaction mixture at regular intervals of time and the extents of the polyesterification reactions were calculated during the formation of alkyds. The structures of synthesized alkyds were confirmed by FT-IR and 1H-NMR spectroscopic analysis and also by end group analysis such as hydroxyl and acid values. The synthesized alkyds were reacted with TDI to prepare PU coatings and their performance was compared with PU coatings prepared from a commercial alkyd.

Herein, we are reporting the green and efficient synthesis of some pharmacologically important azomethine derivatives of isoniazide (INH) using Modified Fly Ash (MFA) as an excellent zeotic solid acid catalyst. The catalyst, by virtue of its terminal hydroxyl groups, forms hydrogen bonds with carbonyl compounds, which activates these reactants for condensation. The MFA was assessed for various aspects like crystallinity, porosity, elemental composition, linkages and also for its stability, which were confirmed with the help of some physical spectral analyses like XRD, BET, EDS, FTIR and TGA. An effective MFA synthesis was achieved by the calcination of an aqueous mixture of fly ash with ferric chloride, successfully incorporating the iron to generate a slightly acidic crystalline zeotic material, which served as an energy efficient catalyst by allowing access to the reaction at room temperature.

An electronically active and spectral sensitive fluorescent "turn-on" chemosensor (BTP-1) based on the benzo-thiazolo-pyrimidine unit was designed and synthesized for the highly selective and sensitive detection of Fe3+ from aqueous medium. With Fe3+, the sensor BTP-1 showed a remarkable fluorescence enhancement at 554 nm (lambda(ex) = 314 nm) due to the inhibition of photo-induced electron transfer. The sensor formed a host-guest complex in 1:1 stoichiometry with the detection limit down to 0.74 nM. Further, the sensor was successfully utilized for the qualitative and quantitative intracellular detection of Fe3+ in two liver cell lines i.e., HepG2 cells (human hepatocellular liver carcinoma cell line) and HL-7701 cells (human normal liver cell line) by a confocal imaging technique. (C) 2014 Elsevier B.V. All rights reserved.

A new fluoride selective fluorescent receptor (13E,19E)-N1′,N3′-bis[4-(diethylamino)-2-hydroxybenzylidene]malonohydrazide (1) was designed and synthesized. Receptor 1 showed a highly selective fluorescent ‘turn-on’ response towards F− among the various tested anions such as F−, Cl−, Br−, I−, HSO4−, H2PO4−, NO2− and CN− in CH3OH:H2O (50:50, v/v), due to the formation of hydrogen bonding host–guest complex in 1:1 stoichiometry with a detection limit of 45.7 nM and association constant of 1.0 × 104 M−1. The nature of interactions between the receptor 1 and F− was investigated by 1H NMR and the probable structure of the 1·F− complex was predicted by B3LYP/6-31G** method.

Renewable resources used in the preparation of polymers are falling in the class of biomaterials which are rich in hydrocarbons and most of the times obtained from parts of profusely available agriculture feedstock. Use of non-edible vegetable oils and their fatty acids are currently the raw materials focused in synthesizing polymeric materials as renewable sources due to increasing economic and environmental concerns of petroleums. The current oil based polymers are prepared by consuming petroleum based anhydrides and dicarboxylic acids. With this investigation, we tried to substitute almost all components of petroleum feed stock by renewable sources in preparation of polyol. Initially palmitic acid was used as a renewable source to prepare palmitamide by amidation reaction. Further amide was converted into the polyesteramide resin (PEPAD) by reacting it with another renewable resource, i.e. dimer fatty acid which is the dimerized product of unsaturated fatty acids of vegetable oils. Structure of the prepared resin was confirmed by spectroscopic techniques and resin was also characterized by end group analysis like hydroxyl and acid values. The molecular weight of PEPAD was ranged between 2590 and 2760 g mol−1. Palmitic acid based polyesteramide was used to prepare polyurethanes by varying amount of diisocyanate. The transparent polyurethane films and coatings were obtained and examined for water absorption, contact angle, hardness, coating properties, solvent, acid and alkali resistances. The thermal properties of the polyurethane films were estimated by TGA and discussed. It was found that change in NCO content affected on transparency as well flexibility of the prepared films. It also noticed that thermal stability was shifted toward higher range by increasing mole (NCO/OH) ratios due to formation of urea linkages.

In the present investigation, nanocomposites of polypropylene (PP)-montmorillonite (MMT) clay were prepared by a single-step compounding method to study the influence of hyperbranched polyester (HBPE) on rheological and mechanical properties of PP composites in the presence of a compatibilizer. In service of this objective, polyvinylchloride-grafted-maleic anhydride (PP-g-MA) was used as a compatibilizer for hydrophobic PP and hydrophilic clay. Rheological property in terms of melt viscosity was examined by a Brabender torque rheometer. The composite's morphology was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), whereas the dispersion state of nanoparticles in the PP matrix was studied by X-ray diffraction (XRD). The thermal behavior of nanocomposites was examined by differential scanning calorimetry (DSC). The analysis of results confirmed that the interactions among both additives significantly influenced the morphology, rheology, and thermomechanical properties of the nanocomposites. J. VINYL ADDIT. TECHNOL., 22:72–79, 2016. © 2014 Society of Plastics Engineers

The present work accounts new approach for processing of PP nanocomposites containing 5 phr pristine Na+ montmorillonite clay with better clay dispersion by a single-step process along with improved processability using hyperbranched polyester (HBPE). A series of PP/MMT nanocomposites with different HBPE contents were fabricated by direct melt compounding on a Brabender torque rheometer where all components of the blends were fed simultaneously for mixing. The efficiency of this approach was evaluated against PP/MMT nanocomposites prepared with polypropylene graft-maleic anhydride (PP-g-MA) compatibilizer. The overall results revealed that systems with HBPE showed better balance of rheology and mechanical properties than nanocomposites with PP-g-MA.

The synergistic effect of layered double hydroxide (LDH) and prepared nano-zinc phosphate was studied by melt compounding of polypropylene (PP) on a Brabender Plastograph. The obtained lumps of com...

The highlight of the work was the preparation of polyesteramide in a one-pot reaction which avoids isolation of diethanol amide as it is normally required in polyesteramide preparation. In the present work, oleic acid was reacted with diethanol amine resulting in diethanol amide which further reacted with phthalic anhydride in the same reaction vessel without isolation and purification. Therefore the reaction is a one-pot, time-saving and cost-effective method as it requires minimum solvent and processing steps. In addition to this, the fatty acid used was a single fatty acid (oleic acid) that provides selective physico- chemical and anticorrosive properties for the resin. FT-IR and 1H-NMR spectroscopic studies confirmed the structure of the polyesteramide. End group analysis and molecular weight were used to calculate the stoichiometric balance of the NCO/OH ratio in the preparation of polyurethane. The prepared resin was converted to polyurethane coatings by reacting with toluene diisocyanate and methylene diphenyl diisocyanate. Thermal stability, physico-chemical and coating properties of the polyurethane coatings were investigated. The polyurethane prepared showed a non-biodegradable nature so that it is of commercial interest and value for applications in various fields. Study of coatings was also carried out for properties like adhesion, impact resistance, pencil hardness and the bending test.

Isophorone diisocyanate (IPDI) trimer based novel polyurea core shell structures were developed by interfacial polymerization. Different operating conditions have been used to fabricate shell to encapsulate core. Characterizations of prepared microcapsules were done by Fourier transform infrared spectroscopy, thermogravimetric analysis, and particle size analyzer. The surface morphology of microcapsules was examined by optical microscopy, scanning electron microscopy, and transmission electron microscopy. The release rate of core from microcapsules was estimated by UV and gas chromatography. The results revealed that tailor made release can be adjusted by varying operational protocol for shell and fabricated shell can be extended to other applications such as self-healing coatings and drug delivery.