Sreekumar, K; Elizabeth, Chirackal Varkey(Wiley, July 20, 2010)
[+]
[-]
Abstract:
The toluene diisocyanate based optically
active chiral polyurethanes were synthesized according to
the symmetry conditions. The noncentrosymmetric (both
charge asymmetry and spatial asymmetry) environment
were attained by the incorporation of the chiral units
(diethyl-(2R,3R)(þ)-tartrate) and donor-acceptor building
blocks in the main chain which induce a helical conformation
in the macromolecular chain. A series of optically
active polyurethanes containing chiral linkages in the
polymer back bone have been synthesized by using
DBTDL catalyst by incorporating the amido diols which
were obtained by the aminolysis of e-caprolactone by
using the diamines, diaminoethane, diaminobutane, and
diaminohexane respectively. The effect of incorporation of
the chiral molecule diethyl-(2R,3R)(þ)-tartrate on the properties
of polyurethanes was studied by changing the chromophores
and also by varying the chiral-chromophore
composition. Various properties of polyurethanes were
investigated by UV, Fluorescence, TG/DTA, XRD, polarimetric
techniques, Kurtz-Perry powder techniques, etc.
Description:
Journal of Applied Polymer Science, Vol. 119, 111–119 (2011)
Ritty J, Nedumpara; Dr. Radhakrishnan, P(Cochin University of Science and Technology, February , 2007)
[+]
[-]
Abstract:
Observing the wide possibilities of fluorescent dyes, an exhaustive investigation is
done in laser dyes mainly focusing on Coumarin 540 which has a very strong
emission in the green region. The photophysics of the dye is studied in detail in a good
number of solvent environments. The results of the amplified spontaneous emission
and lasing behaviour in both dye solution and different polymer solid state matrices
and the ptotostability of the these matrices are investigated using the photoacoustic technique and the same are also included in this thesis. The energy transfer behaviour
in dye mixtures which could be utilized for laser studies and bio-analysis are also
presented. The nonlinear characterization of Coumarin540 forms the last part of the
experimental investigations presented in the thesis.
Description:
International School of Photonics,
Cochin University of Science and Technology