Syed Marghoob Ashraf

Alumina‐Incorporated Polyesteramide from Non‐Edible Seed Oils

To improve the physico‐mechanical and chemical resistance properties, lower the curing temperature of annona squamosa and pongamia glabra seeds oils based polyesteramides [ASPEA, PGPEA], as well as to convert the non‐edible seed oils into value added products, their respective alumina‐incorporated polyesteramides resins [Al‐ASPEA, Al‐PGPEA] have been synthesized. The resins and their coatings have been tested for their chemical, physico mechanical and chemical/corrosion resistance properties. These properties were compared among the prepared resins and with that of previously reported alumina filled linseed polyesteramide [Al‐LPEA]. It was observed that Al‐PGPEA‐71, which has the highest amount of oleic acid chains, shows the best physico‐mechanical and chemical resistance properties.

Tuning the spectral, thermal and fluorescent properties of conjugated polymers via random copolymerization of hole transporting monomers

With the aim to design conjugated copolymers of hole generating monomers, the present paper reports for the first time, ultrasonic-assisted synthesis of poly(o-phenylenediamine) and polycarbazole using different molar ratios of the two monomers. The copolymerization was established by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, ultraviolet-visible spectroscopy and differential theromogravimetric analysis while the morphology was investigated using X-ray diffraction and transmission electron microscopy studies. The copolymer composition was confirmed by nuclear magnetic resonance spectroscopy which matched with the molar feed ratio. Reactivity ratios (r1 and r2 values) confirmed random copolymerization. Infrared spectra revealed that values increased with the increase in the poly(o-phenylenediamine) units. Cyclic voltammetry also confirmed copolymerization. Oxidation and reduction potentials corresponding to the redox peaks of o-phenylenediamine and carbazole copolymers of different composition were close to each other, but fairly different from those of the pure polymers. Redox current densities of copolymers of different compositions were found to vary with the composition. Ultraviolet-visible spectroscopy studies also revealed a progressive change in the optical properties as the copolymer composition changed from 90–10% polycarbazole. X-ray diffraction studies showed morphology of the copolymers to be an intermediate between PCz and POPD where PCz polymer chains appeared least compact and the poly(o-phenylenediamine) chains appeared more close and compact. Fluorescence studies confirmed that as the ratio of poly(o-phenylenediamine) in the copolymer increased from 30–90%, quantum yield increased from 0.27–0.37. Thermogravimetric analysis and differential theromogravimetric studies confirmed copolymerization of the monomers and showed two types of copolymer complexions which were consistent with the experimentally determined copolymerization ratio.

Influence of Conducting Polymer as Filler and Matrix on the Spectral, Morphological and Fluorescent Properties of Sonochemically Intercalated poly(o-phenylenediamine)/Montmorillonite Nanocomposites.

BACKGROUNDnNanocomposites consisting of spatially confined polymeric chains are of great interest due to their application in optoelectronic and photonics devices. Polymer layered silicate nanocomposites have attracted much attention in industry as well as academia owing to their remarkable physical and chemical properties as compared to conventional polymer nanocomposites.nnnMETHODSnIn present study, comparative investigation of the in-situ polymerization of poly(ophenylenediamine) intercalated montmorillonite has been done via two methods i.e using poly(o-phenylenediamine) as filler for MMT in one case and as matrix in the other. Intercalation and in-situ polymerization was confirmed by FT-IR, UV-Visible spectroscopy and XRD studies. TEM and optical microscopy studies confirmed the self-assembled morphology of nanocomposites while the fluorescence properties revealed that controlled emission could be achieved by confining poly(o-phenylenediamine) in MMT galleries.nnnRESULTnIntercalation and in-situ polymerization of o-phenylenediamine within MMT was successfully carried out using sonochemical technique. The growth of conducting polymers in the interlayer region of the clays has been shown to dramatically improve the properties of conducting polymers. Also, the loading of the polymer in the MMT has shown to influence the optical properties of the nanocomposite. IR spectra and XRD analysis confirmed the intercalation of POPD and its polymerization within the clay galleries. UV spectra revealed the doped state of POPD within clay galleries. Highest oscillator strength of 0.0137 was observed for POPD:MMT-1:0.25. Spherical self-assembled morphology was attained for POPD:MMT-1:0.25. XRD revealed major shift of 82.5 Å for the nanocomposite POPD:MMT-1:1, POPD:MMT-1:0.5 and MMT:POPD-1:0.25. Blue shift of 20 nm was noticed in the fluorescence spectra of POPD:MMT-1:0.25 and POPD:MMT-1:0.5 which was correlated to the intense interaction between NH of POPD with SiO of MMT. Highest quantum yield of 0.345 was achieved in case of POPD:MMT-1:0.25. The gallery confinement was found to control the optical as well as morphological characteristics of the nanocomposite. The controlled growth of POPD chains and their minimum aggregation resulted in the formation of self-assembled morphology. Thus, by choosing the optimum filler loading and by controlling its interaction with the matrix, nanocomposites with controlled architecture can be designed.nnnCONCLUSIONnIt can be concluded that intercalation and exfoliation of nanocomposites largely depends on the experimental conditions such as type of conducting monomer, clay and organic modifier etc. The preparation technique and processing conditions influence the overall properties of the nanocomposites. Thus, by choosing the optimum filler loading and by controlling its interaction with the matrix, nanocomposites with controlled architecture can be designed. Few relevant patents to the topic have been reviewed and cited.

Influence of Luminol Doping of Poly(o-phenylenediamine) on the Spectral, Morphological, and Fluorescent properties: A Potential Fluorescent Marker for Early detection and Diagnosis of Leishmania donovani

There has been a steady progress in the development of doped conjugated polymers to remarkably improve their photo physical properties for their application as biomarkers. With a view to enhance the spectral, morphological, and photo physical properties of poly(o-phenylenediamine) (POPD), the present work reports the synthesis of poly(o-phenylenediamine) and doping of this polymer using luminol. The formation of luminol-doped POPD was confirmed by infrared and ultraviolet-visible spectroscopies and X-ray diffraction studies. The energy band gap values and oscillator strength of luminol in acidic, basic, and neutral media were computed by density functional theory calculations using the B3LYP/6-31G (d) basis set and were compared with experimental data. The luminol doped POPDs show significant in vitro anti-leishmanial activity. Live cell imaging also proved that these molecules bind with the organelle of Leishmania also. These luminol doped POPDs were found non-toxic at the used concentrations on THP-1 derived human macrophage cells through methyl tetrazolium (MTT) assay. The results revealed that luminol doped POPDs were potentially non-toxic to human cells though exhibited immense potential to be used as a fluorescent marker to label Leishmania donovani for diagnostic and other studies.