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β-Carboline and γ-lactone moieties have been selected by nature as privileged scaffolds and display a wide range of pharmacological properties. Following nature, we envisaged the preparation of new β-carboline and γ-lactone based molecular hybrids incorporating both the pharmacophores. In this regard, a water-assisted In-mediated environmentally benign and easy to execute single-step tandem Barbier type allylation-lactonisation process has been devised in order to afford the targeted molecular architectures. It is anticipated that aqueous medium plays the key role in allylation as well as in the subsequent lactonisation process for the diastereo-selective synthesis of these conjugates. It is believed that water drives the reaction pathway through dual activation, it increases the electrophilic character of formyl and ester functionalities and simultaneously enhances the nucleophilic potential of the hydroxyl group to facilitate the in situ intramolecular condensation. Importantly, during this synthetic strategy no column chromatographic purification was required at any stage.

Polymer nanocomposites (NCs) are a special class of materials having unique properties and wide application potential in electronics and other diverse areas. In this study, NCs consisting of poly(3,4‐ethylenedioxythiophene)/poly(4‐styrene sulfonate) (PEDOT:PSS) matrix reinforced with graphite nanosheets were fabricated by solution method. The graphite used was functionalized before fabrication of NCs. The functionalized graphite was characterized by transmission electron microscopy (TEM) and Fourier transform Infrared spectroscopy (FTIR) technique. The NCs prepared were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and FTIR technique. The conductivity studies of the prepared NCs were carried out. The prepared NCs films were investigated for the detection of nitrobenzene vapors. The detection mechanism is based on measuring resistivity changes that occur in a NC due to the absorption of nitrobenzene vapors by PEDOT:PSS film. These sensors exhibited excellent response at room temperature when exposed to vapors of nitrobenzene. Sensitivity as high as 18.5% was observed for PEDOT:PSS/NGPs composite. The chemresistor exhibits a fast response (∼1.14 min) and good recovery time (∼1–2 min). The response of NC to the nitrobenzene vapors is reproducible. POLYM. ENG. SCI., 53:2045–2052, 2013. © 2013 Society of Plastics Engineers

We report the synthesis of a novel photocleavable crosslinker and its joining with amine-based polysachharides, viz. chitosan, resulting in the formation of a dual stimuli-responsive hydrogel having UV- and pH-responsive sites.

In this work, we report the synthesis of robust, flexible, and free standing PMMA/NGP (nanographitic platlets) composite by one‐pot polymerization technique for sensing organic vapors. The synergy between the NGPs and PMMA matrix through strong interaction results in remarkable electrical and sensing properties of the composite system. The chemical structure and morphology of as‐prepared PMMA/NGP composites were investigated by using FTIR, XRD, and SEM techniques. The electrical conductivity of the prepared PMMA/NGP composites increases with increasing concentration of NGPs owing to the formation of conductive paths within the composite due to the quantum tunneling mechanism. The electrical conductivity of PMMA/NGP composites with different NGP concentration shows a percolation behavior with percolation threshold of ∼1.2 wt%. The temperature dependent conductivity studies of the PMMA/NGPs were studied to understand the charge transport mechanism in the composite films by using Mott's Variable range hopping model. The PMMA/NGP composite have been evaluated for detection of benzene, toluene, and xylene vapors and were found to exhibit fast response, rapid recovery, and excellent repeatability. The sensitivity along with the flexibility of PMMA/NGP composite films opens up a new opportunity to fabricate the sensor in any shape as per the requirement of modern electronics. POLYM. ENG. SCI., 58:1074–1081, 2018. © 2017 Society of Plastics Engineers

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Grafted membranes were prepared through chemical graft copolymerization of methyl methacrylate (MMA) onto isotactic polypropylene film (IPP). The IPP films were grafted with MMA molecules resulting in IPP-g-MMA grafts using benzoyl peroxide as an initiator in an inert nitrogen atmosphere. Using this method, the degree of grafting and morphology could be controlled through the variation of reaction parameters such as initiator concentration, monomer concentration, reaction time, and the reaction temperature. Optimum conditions pertaining to maximum percentage of grafting (%G) were evaluated as a function of these parameters. Maximum percentage of grafting (50%) was obtained at  M, % V/V, and [Reaction Temperature] = in a [Reaction time] of 120 minutes. IPP-g-MMA films were investigated for their swelling behavior. Water-swelling analysis of IPP-g-MMA was carried out as a function of different percentage of grafting, temperatures, and time. Maximum swelling percentage of IPP-g-MMA (92%) was observed in 8 hours at . The evidence of grafting was carried out by Fourier transform spectroscopy (FTIR), atomic force microscopy (AFM), and scanning electron microscopy (SEM) before and after grafting, respectively. The swelling pattern was characterized by two distinct stages, an initial diffusion-controlled fast swelling, followed by a subsequent slower process controlled by the relaxation of polymer fragments. Swelling chrematistics of IPP-g-MMA make it a potentially useful material.

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