Dr. Sreekumar Khttps://dyuthi.cusat.ac.in:443/xmlui/handle/purl/6912024-02-07T16:52:13Z2024-02-07T16:52:13ZSynthesis And Characterization Ofpolystyrene Supportedcatalytically Active Poly(Amidoamine) Dendrimer-Palladium Nanoparticle ConjugatesSreekumar, KRajesh Krishnan, Ghttps://dyuthi.cusat.ac.in:443/xmlui/handle/purl/40162014-07-14T20:30:32Z2010-02-22T00:00:00ZSynthesis And Characterization Ofpolystyrene Supportedcatalytically Active Poly(Amidoamine) Dendrimer-Palladium Nanoparticle Conjugates
Sreekumar, K; Rajesh Krishnan, G
Poly(amidoamine) dendrimers were synthesized on cross-linked aminomethyl polystyrene. Palladium
complexes of supported dendrimers prepared by ligand exchange method were reduced to dendrimernanoparticle
conjugates supported on polystyrene resin. The supported nanoparticles were used as
heterogeneous catalysts for the Suzuki coupling between aryl boronic acids and aryl halides. Various factors
affecting the catalysts performance were studied. Higher generation dendrimers gave well-defined
nanoparticles without agglomeration and these particles showed good catalytic performance
Soft Materials, 8(2):114–129, (2010)
2010-02-22T00:00:00ZIsosorbide based chiral polyurethanes: optical and thermal studiesSreekumar, KElizabeth, Chirackal Varkeyhttps://dyuthi.cusat.ac.in:443/xmlui/handle/purl/40152014-07-14T20:30:31Z2010-01-13T00:00:00ZIsosorbide based chiral polyurethanes: optical and thermal studies
Sreekumar, K; Elizabeth, Chirackal Varkey
A new class of chiral polyurethanes containing
amido linkages in the polymer backbone have been synthesized
by reacting toluene diisocyanate with isosorbide
(IS) chiral moiety and the chromophores [N,N0-ethane-
1,2-diyl bis(6-hydroxy hexanamide), N,N0-butane-1,4-diyl
bis(6-hydroxy hexanamide) and N,N0-hexane-1,6-diyl bis
(6-hydroxy hexanamide)]. The corresponding chromophores
were obtained by the aminolysis of e-caprolactone by
using the diamines, diaminoethane, diaminobutane and
diaminohexane, respectively. All the polymers were synthesized
according to the symmetry conditions so as to
obtain the non-centrosymmetric environment. A series of
polyurethanes were synthesized by varying the chiral–
chromophore composition. The polyurethanes developed
were characterized by optical and thermal methods.
J Mater Sci (2010) 45:1912–1920
DOI 10.1007/s10853-009-4177-1
2010-01-13T00:00:00ZSynthesis and Properties of Polyurethanes of Hexamethylene Di-Isocyanate with Multifunctional Chromophores in the Main ChainSreekumar, KSudheesh Kumar, Khttps://dyuthi.cusat.ac.in:443/xmlui/handle/purl/40142014-07-14T20:30:31Z2007-06-01T00:00:00ZSynthesis and Properties of Polyurethanes of Hexamethylene Di-Isocyanate with Multifunctional Chromophores in the Main Chain
Sreekumar, K; Sudheesh Kumar, K
Various polyurethanes containing photoactive bis(azo) and bis(o-nitrobenzyl)
groups in the main chain were synthesized by polyaddition reactions of diols such
as bis(4-hydroxyphenylazo)-2,20-dinitrodiphenylmethane, 4-hydroxy-3-methylphenylazo-
40-hydroxyphenylazo-2,20-dinitrodiphenylmethane and bis(4-hydroxy-3-
methylphenylazo)-2,20-dinitrodiphenylmethane with hexamethylene di-isocyanate
(HMDI), in dimethyl acetamide (DMAc) in the presence of di-n-butyltin dilaurate
(DBTDL) as catalyst. All of them were characterized by IR, UV-vis, 1H NMR and
13C NMR spectra and also by thermogravimetric analysis (TGA), differential scanning
calorimetry (DSC) and gel permeation chromatography (GPC).
International Journal of Polymeric Materials, 58:160–166, 2009
2007-06-01T00:00:00ZRecording multiple holographic gratings in silver-doped photopolymer using peristrophic multiplexingSreekumar, KRani, JosephPramitha, VSudha Kartha, Chttps://dyuthi.cusat.ac.in:443/xmlui/handle/purl/40132014-09-20T09:53:19Z2010-12-01T00:00:00ZRecording multiple holographic gratings in silver-doped photopolymer using peristrophic multiplexing
Sreekumar, K; Rani, Joseph; Pramitha, V; Sudha Kartha, C
Plane-wave transmission gratings were stored in the same location of silver-
doped photopolymer ¯lm using peristrophic multiplexing techniques. Constant and vari-
able exposure scheduling methods were adopted for storing gratings in the ¯lm using
He{Ne laser (632.8 nm). The role of recording geometry on the dynamic range of the ma-
terial was studied by comparing the results obtained from both techniques. Peristrophic
multiplexing with rotation of the ¯lm in a plane normal to the bisector of the incident
beams resulted in better homogenization of di®raction e±ciencies and larger M/# value.
Pramana { J. Phys., Vol. 75, No. 6, December 2010
2010-12-01T00:00:00Z