01968nas a2200253 4500008004100000022001400041245005100055210005100106260010600157300001400263490000700277520114600284653002701430653001801457653001801475653001801493100002401511700001901535700001901554700001901573700001801592700002101610856008301631 2007 eng d a0009-250900aSpinning wave motion in frontal polymerization0 aSpinning wave motion in frontal polymerization aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcMAR a1448-14550 v623 a

We present a mathematical model describing dynamics of spinning waves which propagate during frontal polymerization reaction taking place in a cylindrical reactor tube. The self-organization of spatio-temporal solution of wave equations due to interplay between thermal diffusion and kinetics gives rise to pattern formation. We begin with a fundamental equation of motion of radial coordinate after defining an asymptotic phase for spinmode. The motion is analyzed near a critical (Hopf) point and a perturbation solution is used to obtain patterns for a case of preparation of poly(2-hydroxyethyl methacrylate) (PHEMA) via frontal polymerization reaction. The model uses the distance as seen in photograph taken using scanning electron microscope (SEM) from which motion begins around core of spiral and calculates pitch of spiral which matches closely with experimental observation in micrograph. Also the model predicts qualitatively the ramp wave and spiral wave motion as observed under SEM. Both these results are reported in open literature for the first time to our best knowledge. (c) 2006 Elsevier Ltd. All rights reserved.

10afrontal polymerization10aspinning wave10aspiral motion10awave dynamics1 aInamdar, Satish, R.1 aPujari, N., S.1 aKarimi, I., A.1 aPonrathnam, S.1 aTayal, R., K.1 aKulkarni, B., D. uhttps://library.ncl.res.in/content/spinning-wave-motion-frontal-polymerization01860nas a2200181 4500008004100000022001400041245013100055210006900186260005700255300001400312490000700326520111700333100002901450700003001479700001901509700001801528856013201546 2011 eng d a0022-246100aSynthesis and photopolymerization kinetics of linear alicyclic urethane acrylate macromonomer in presence of reactive diluents0 aSynthesis and photopolymerization kinetics of linear alicyclic u a233 SPRING ST, NEW YORK, NY 10013 USAbSPRINGERcAPR a2221-22280 v463 a

This study deals with the photopolymerization of a macromonomer in the presence of reactive diluents using Photo Differential Scanning Calorimetry or Photo DSC. The kinetic profiles of these systems showed that the rate of photopolymerization rapidly increases at very early stages of the reaction. The rate of reaction was further found to increase with the addition of crosslinking agents. The addition of trifunctional crosslinking agent to the macromonomeric formulation resulted in a higher polymerization rate and conversion than that of a difunctional crosslinking agent. From the heat flow profiles, the kinetic parameters such as induction time, time to attain peak maximum, rate of maximum polymerization, and final conversion were noted for all the formulations. The initiation of photopolymerization was found to depend on the functionality while the in situ viscosity controlled the time scale for reaction diffusion which resulted in varying levels of conversions. Other parameters such as effect of temperature and concentration of photoinitiator on photocuring kinetics are also discussed.

1 aHarikrishna, Reghunathan1 aBhosle, Sonali, Madhavrao1 aPonrathnam, S.1 aRajan, C., R. uhttps://library.ncl.res.in/content/synthesis-and-photopolymerization-kinetics-linear-alicyclic-urethane-acrylate-macromonomer-001797nas a2200241 4500008004100000022001400041245016500055210006900220260010000289300001200389490000600401520080400407653003201211653002601243653001901269653003001288653002301318100002701341700001801368700001901386700001901405856013101424 2015 eng d a1788-618X00aSynthesis of novel silica-polyimide nanocomposite films using aromatic-amino modified silica nanoparticles: mechanical, thermal and morphological investigations0 aSynthesis of novel silicapolyimide nanocomposite films using aro aDEPT POLYMER ENG, MUEGYETEM RKP 3, BUDAPEST, H-1111, HUNGARYbBUDAPEST UNIV TECHNOL & ECONcMAY a469-4790 v93 a

Silica nanoparticles were modified with aromatic amino groups and modified-silica/polyimide composite films were prepared using them. 3,3!, 4,4!-Benzophenone tetracarboxylic dianhydride (BTDA) and 4,4!-oxydianiline (ODA) were used as precursors for polyimide matrix. The structures of the modified nanoparticles and hybrid nanocomposites were identified using Fourier Transform Infrared (FTIR) spectrometry. The hybrid composite films were evaluated for mechanical, thermal and morphological characteristics. Morphological results describe a uniform dispersion of silica particles in the polymer matrix. The thermal stability and mechanical properties of polyimide composite were improved, and the decomposition temperature was increased when the amount of silica nanoparticles was increased.

10ahybrid polyimide composites10amechanical properties10aNanocomposites10ananoparticle modification10aThermal properties1 aGhorpade, Ravindra, V.1 aRajan, C., R.1 aChavan, Nayaku1 aPonrathnam, S. uhttps://library.ncl.res.in/content/synthesis-novel-silica-polyimide-nanocomposite-films-using-aromatic-amino-modified-silica-002137nas a2200229 4500008004100000022001400041245015800055210006900213260008700282300001000369490000700379520120700386653003701593653001401630653002901644100002701673700002401700700001801724700001901742700001901761856012701780 2016 eng d a0954-008300aSynthesis and characterization of thermally stable polyimides with a pendent phenothiazine unit based on new diamine 10-(3,5-diaminobenzoyl)phenothiazine0 aSynthesis and characterization of thermally stable polyimides wi a1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLANDbSAGE PUBLICATIONS LTDcFEB a26-330 v283 a

A novel diamine 10-(3,5-diaminobenzoyl)phenothiazine (DBPT) with a side chain containing phenothiazine unit was synthesized. A new family of polyimides (PIs) containing phenothiazine unit in the side chains has been successfully synthesized by direct polycondensation of DBPT with pyromellitic dianhydride, 3,3',4,4'-benzophenone tertacarboxylic dianhydride, and 4,4'-oxydiphthalic anhydride (ODA) via a conventional two-step chemical imidization process. The yield of polymers was good enough, which were soluble in most organic solvents. The molecular orbital energy gaps, thermal stability, and crystallinity of PIs were investigated by molecular modeling, thermogravimetric analysis, and wide-angle X-ray scattering, respectively. Thermal properties of polymers were good enough to permit the use of these PIs in various applications; only 49% weight loss is detected at 900 degrees C in nitrogen atmosphere. X-Ray diffraction clearly reveals the amorphous nature of PIs. A quantum modeling study (density functional theory) has shown the influence of dianhydride structure on the energy difference of highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels.

10aphenothiazine-containing diamine10aPolyimide10athermally stable polymer1 aGhorpade, Ravindra, V.1 aThorave, Asmita, K.1 aRajan, C., R.1 aChavan, Nayaku1 aPonrathnam, S. uhttps://library.ncl.res.in/content/synthesis-and-characterization-thermally-stable-polyimides-pendent-phenothiazine-unit-0