Thommachan, Xavier; Dr.Thomas, Kurian(Cochin University of Science & Technology, March , 2002)
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Abstract:
Chemically modified novel thermo-reversible zinc sulphonated ionomers based on natural
rubber (NR), radiation induced styrene grafted natural rubber (RI-SGNR), and chemically induced
styrene grafted natural rubber (CI-SGNR) were synthesized using acetyl sulphate/zinc acetate
reagent system. Evidence for the attachment of sulphonate groups has been furnished by FTIR
spectra. which was supplanted by FTNMR results. Estimation of the zinc sulphonate group was
done using spectroscopic techniques such as XRFS and ICPAES. The TGA results prove
improvement in the therrno-oxidative stability of the modified natural rubber. Both DSC and DMTA
studies show that the incorporation of the ionic groups affect the thermal transition of the base
polymer. Retention of the improved physical properties of the novel ionomers even after three
repeated cycles of mastication and molding at 120 degree C may be considered as the evidence for the
reprocessabiJity of the ionomer. Effect of both particulate (carbon black. silica & zinc stearate) and
fibrous fillers (nylon & glass) on the properties of the radiation induced styrene grafted natural
rubber ionomer has been evaluated. Incorporation of HAF carbon black results in maximum
improvement in physical properties. Silica reinforces the backbone chain and weakens the ionic
associations. Zinc stearate plays the dual role of reinforcement and ptasticization. The nylon and
glass filled lonorner compounds show good improvement in the physical properties in comparison
with the neat ionomer. Dispersion and adhesion of the fillers in the ionomer matrix has been amply
supported by their SEM micrographs. Microwave probing of the electrical behavior of the 26.5 ZnSRISGNR
ionomer reveals that the maximum relative complex conductivity and the complex
permittivity appear at the frequency of 2.6 GHz. The complex conductivity of the base polymer
increases from 1.8x 10.12 S/cm to 3.3xlO·4 S/cm. Influence of fillers on the dielectric constant and
conductivity of the new ionic thermoplastic elastomer has been studied. The ionomer I nylon
compound shows the highest microwave conductivity. Use of the 26.5 ZnS-RISGNR ionomer as a
compatibilizer for obtaining the technologically compatible blends from the immiscible SBR/NBR
system has been verified. The heat fugitive ionic cross-linked natural rubber may be, therefore,
useful as an alternative to vulcanized rubber and thermoplastic elastomer
Description:
Department of Polymer Science and Rubber Technology, Cochin University of Science and Technology
Rani, Joseph(John Wiley & Sons, Inc., November 1, 2000)
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Abstract:
ABSTRACT: p-Phenylenediamine was chemically attached to low molecular weight chlorinated
paraffin wax. The polymer-bound p-phenylenediamine was characterized by
vapor-phase osmometry (VPO), proton magnetic resonance spectroscopy ('H-NMR),
infrared spectroscopy (IR), and thermogravimetric analysis (TGA). The efficiency and
permanence of the polymer-bound p-phenylenediamine as an antioxidant was compared
with a conventional amine-type antioxidant in natural rubber vulcanizates. The
vulcanizates showed improved aging resistance in comparison to vulcanizates containing
a conventional antioxidant. The presence of liquid polymer-bound p-phenylenediamine
also reduces the amount of the plasticizer required for compounding.
Mohammed Yusuff, K K; Mayadevi, S(Taylor & Francis, 1997)
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Abstract:
Some new transition metal complexes of the Schiff base
quinoxaline-2-car boxalidene-2-aminophenol (HQAP) have been
synthesized and characterized by elemental analyses, conductance
and magnetic measurements and IR and UV-Visible spectral studies.
The complexes have the following empirical formulae: [Mn(QAP121,
[Fe(QAPl2C1I, [Co(QAPl21, [Ni(QAP121 and [Cu(QAP121. A tetrahedral
structure has been assigned for the manganese(=), cobalt(II1,
nickel(II1 and copper(II1 complexes. For the iron(IIIl complex an
octahedral dimeric structure has been suggested
Saravanan, S; Dr Anantharaman, M R; Dr.Venkatachalam, S(Cochin University of Science & Technology, November , 2003)
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Abstract:
In this work polymers belonging to polyaniline and polyaniline doped
with camphor sulphonic acid are synthesised. Cobalt phthalocyanine is an
interesting candidate belonging to the tetramers. Studies on the composites
containing cobalt phthalocyanine tetramer and polyaniline doped with camphor
sulphonic acid for various concentration are also undertaken in order to understand
the mechanism. RF plasma polymerised aniline and furfural are prepared. The
structural and electrical properties are evaluated. The bombardment of swift heavy
ions of these films are carried out and the effect of irradiation on their properties is
also investigated.
Description:
Department of Physics,
Cochin University of Science and Technology
Chandini,R Nayar; Prathapachandra Kurup,M R(Department of Applied Chemistry, 2002)
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Abstract:
Coordination chemistry of schiff bases is of considerable interest due to their various magnetic, catalytic and biological applications. Here it describes the spectral characterization of schiff bases and its Mn (II), Cu (II) and Ni (II) complexes. Then synthesis and spectral characterization of Zn (II), Cd (II) and Co (II) complexes of schiff base derived from 3-Formylsalicilic Acid and 1,3-diaminopropane. Then it discusses the synthesis and spectral studies of Copper (II) complexes of 2-Hydroxyacetophenone N-phenyl semicarbazone. Finally it discusses the synthesis and spectral characterization of Co (III) complexes of salicylaldehyde N-phenyl semicarbazone. The preparation and characterization of Cobalt (III) complexes of salicylaldehyde, N-phenylthiosemicarbazone containing hetrocyclic bases phenalthroline and bipyridine. Thiocyanate, azide and perchlorate ions act as coligands. Elemental analysis suggests +3 state for Cobalt. HNMR, IR and UV-visible spectra characterize the complexes.
Sreesha, Sasi; Prathapachandra Kurup, M R; Suresh, E(Springer, January 1, 2007)
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Abstract:
The cobalt(III) complex, [Co(L)2(N3)2]2(ClO4)2, L being a Schiff base N-[phenyl(pyridin-2-yl)methylene]aniline has been synthesized and the crystal structure determined using X-ray crystallography. The complex crystallizes in triclinic system, space group P-1 with unit cell parameters a=10.9367(9) , b=18.0817(17) , c=20.1629(16) , α=111.341(2), β=91.622(2), γ=107.5030(10), V=3499.1(5) 3 and Z=2. It crystallizes with two independent molecules in the asymmetric unit. The two cobalt atoms are hexa-coordinate and have a distorted octahedral geometry, satisfied by four nitrogen atoms from two molecules of the Schiff base and two nitrogen atoms from the monodentate azide group. The perchlorate ions are non-coordinating.
Bindu, Krishnan; Dr.Nampoori, V P N(Cochin University of Science & Technology, April , 2005)
[+]
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Abstract:
Over the past few years, a little word with big potential has been rapidly entering into the world's consciousness-'nano'. Nanoscience and technology is a multidisciplinary field, involving the fabrication and understanding of matter at the finest level of a few nanomters.This thesis is about the synthesis and laser induced studies of nanosized ZnO,a versatile material with a wide range of applications.After synthesizing colloids and films of nano ZnO,the samples are studied using different optical methods.Interactions of intense laser beams with nanosized particles are found to open up many interesting scenarios with possible applications in the field of photonics.
Description:
International School of Photonics,
Cochin University of Science and Technology
Ambily Mary, Jacob; Dr. Prathapan, S(Cochin University of Science & Technology, March , 2008)
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Abstract:
The thesis entitled: ‘Synthesis and Photochemistry of a few Olefin
appended Dibenzobarrelenes and Bisdibenzobarrelenes’ is divided into 5
chapters.In Chapter 1, the fundamental concepts of Diels-Alder reaction, di-r:methane
rearrangement and energy transfer process in organic photochemistry
is discussed.Chapter 2 presents the synthesis of 9-olefin appended
anthracenes and bisanthracenes. The target of synthesising various bridgehead olefin appended
dibenzobarrelenes and some novel bisdibenzobarrelenes, led us to the
synthesis of the appropriate alkenylanthracenes and bisanthracenes as
precursor molecules. Diels-Alder reaction was the synthetic tool for the
preparation of the target olefin appended dibenzobarrelenes and
bisdibenzobarrelenes. This chapter attempts to throw light on our endeavours
in synthesising the various 9-alkenylanthracenes and bisanthracenes.Chapter 3 deals with the synthesis of olefin
appended dibenzobarrelenes and bisdibenzobarrelenes.
Ever since the discovery of di-It-methane rearrangement
dibenzobarrelenes, tailored with dijferent substituents at various positions
have always been a tool to photochemists in unravelling the mechanisms of
light induced reactions. Our intention of analysing the role of a It-moiety at
the bridgehead position of the dibenzobarrelene, was synthetically envisaged
via the Diels-Alder reaction. Bisdibenzobarrelenes were synthesised through
tandem Diels-Alder reaction. Various alkenylanthracenes and bisanthracenes
were employed as dienes and the dienophiles used were dimethyl
acetylenedicarboxylate and dibenzoylacetylene. In this chapter, we report our
venture in synthesising the various olefin appended dibenzobarrelenes and
bisdibenzobarrelenes. Chapter 4 describes
the preliminary time-resolved fluorescence studies of some olefin appended
dibenzobarrelenes and bisdibenzobarrelenes.To understand the primary and secondary physicochemical processes
in a photochemical reaction it is necessary to characterise the excited states
and the transient intermediates during their short lifetime. A number of
methods developed on the basis of the physical properties of the transient
species are available for their detection. Time-correlated single-photon
counting technique has been utilised in the present study of the excited states
of olefin appended dibenzobarrelenes and bisdibenzobarrelenes.
To understand the primary and secondary physicochemical processes
in a photochemical reaction it is necessary to characterise the excited states
and the transient intermediates during their short lifetime. A number of
methods developed on the basis of the physical properties of the transient
species are available for their detection. Time-correlated single-photon
counting technique has been utilised in the present study of the excited states
of olefin appended dibenzobarrelenes and bisdibenzobarrelenes.Chapter 5 portrays the
photochemistry of olefin appended dibenzobarrelenes and
bisdibenzobarrelenes. Dibenzocyclooctatetraene and dibenzosemibullvalene are the
photoproducts obtained respectively through the singlet excited state and the
triplet excited state of dibenzobarrelenes. Chemical literature shows
evidences of the photoreactivity of dibenzobarrelenes generating both the
singlet and triplet mediated photoproducts, in a single photoreaction. Our
research target in synthesising various bridgehead olefin appended
dibenzobarrelenes and bisdibenzobarrelenes, was based on the perception
that olefins are eflicient triplet quenchers, thereby quenching intramolecularly
the triplet excited state of the barrelenes. A It-moiety at the bridgehead
position of the dibenzobarrelene, creates a tetra tr-methane system, which
similar to a 6li—7l' or tri-tr-methane systems, could be the fertile ground for
interesting photochemical rearrangements. Our attempts in deciphering the
photochemistry of the olefin appended dibenzobarrelenes and
bisdibenzobarrelenes is the substance of this chapter.
Description:
Department of Applied Chemistry,
Cochin University of Science and
Technology
A series of nonelectrolytic lanthanide(III) complexes,
[
ML
2
Cl
3
]
·
2
H
2
O, where M is lanthanum(III),
praseodymium(III), neodymium(III), samarium(III), gadolinium(III), terbium(III), dysprosium(III), and
yttrium(III), containing sulfamethoxazole ligand (L) are prepared. The structure and bonding of the ligand are
studied by elemental analysis, magnetic susceptibility measurements, IR,
1
H NMR,
TG
/
DTA
, X-ray diffraction
studies, and electronic spectra of the complexes. The stereochemistry around the metal ions is a monocapped
trigonal prism in which four of the coordination sites are occupied by two each from two chelating ligands, sulfonyl
oxygen, and nitrogen of the amide group and the remaining three positions are occupied by three chlorines.
The ligand and the new complexes were tested in
vitro to evaluate their activity against the bacteria
Escherichia
coli
and
Staphylococcus
aureus.
Rahna, K Shamsudeen; Nisha, K; Sugunan, S(November , 2002)
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Abstract:
Iron pillared Montmorillonite has been synthesised and it is then wet impregnated with vanadia with different vanadia
composition. These catalysts are characterised using conventional techniques such as XRD analysis,FTIR analysis and
surface area and pore volume measurements. Acidity is measured using spectrophotometric monitoring of adsorption of
perylene, thermogravimetric desorption of 2.6 dimethylpyridine and temperature programmed desorption of ammonia.
Activity studies are done in the liquid phase. It has been concluded that Lewis acidic sites are responsible for the benzylation
of toluene when the benzylating agent is benzyl chloride while Bronsted acidic sites are responsible when the reagent is
benzyl alcohol.
The (Ba1-x Srx) (Nd1/2, Nb1/2) O3 ceramics have been prepared by the conventional
ceramic route for different values of x. Addition of a small amount of
CeO2(1 wt%) as a sintering aid increased the density of the samples. The structure
and microstructure of the sintered samples are studied by X-ray diffraction
and SEM methods. The dielectric properties of the samples are measured in the
microwave frequency region as a function of composition. The dielectric constant
decreases as x increases. The coefficient of thermal variation of resonant
frequency decreases as the Sr content increases and goes to the negative side.
The dielectric properties of (Ba1-x Srx) (Nd1/2, Nb1/2) O3 are in the range suitable
for application as dielectric resonators in microwave circuits