02176nas a2200253   4500008004100000022001400041245009300055210006900148260006700217300001400284490000800298520119700306653005201503653004401555653002301599653003001622653003701652653001401689100002801703700002401731700002301755700001901778856012501797       2006                        eng d  a0021-899500aSynthesis and characterization of cholesteric thermotropic liquid crystalline polyesters0 aSynthesis and characterization of cholesteric thermotropic liqui  a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcJAN  a1232-12370 v1033 a<p>Cholesteric liquid crystalline polyesters were successfully synthesized from isosorbide, methyl hydroquinone, and isophthaloyl chloride. Homo/copolyesters were synthesized by the solution polycondensation method, for which a mild organic base such as pyridine was employed. Inherent viscosities of polyesters P-3-P-5 were in the range of 0.31-0.39 dL/g at 25 degrees C in chloroform, and polyesters P-1 and P-2 were insoluble in chloroform. Homo/copolyesters based on isosorbide, methyl hydroquinone, and isophthalic acid had thermal stability at more than 300 degrees C on the basis of 10% weight loss. The thermotropic liquid crystalline properties were examined by differential scanning calorimetry and polarizing optical microscopy. Wide-angle X-ray diffraction study demonstrated that polyesters P-1, P-2, and P-3 were semicrystalline, whereas the degree of crystallinity of polyesters P-4 and P-5 was less than 5%. Copolyester P-4 showed formation of a yellow iridescent streak at 209 degrees C on heating and development of a Grand-jean texture at 270 degrees C on heating. These are typical textures of the cholesteric liquid crystalline phase. (c) 2006 Wiley Periodicals, Inc.</p>10acholesteric liquid crystalline polymers (ChLCP)10aDifferential scanning calorimetry (DSC)10aoptical microscopy10asolution polycondensation10aThermogravimetric analysis (TGA)10aviscosity1 aJadhav, Sushilkumar, A.1 aChougule, Rahul, R.1 aShinde, Yogesh, A.1 aChavan, Nayaku  uhttps://library.ncl.res.in/content/synthesis-and-characterization-cholesteric-thermotropic-liquid-crystalline-polyesters02425nas a2200265   4500008004100000022001400041245011200055210006900167260000800236300001500244490000600259520150600265653002701771653002401798653003001822653001601852653002001868100002501888700002301913700002101936700002601957700002001983700002802003856012802031       2022                        eng d  a2365-654900aSynthesis, characterization and UV-crosslinking of aromatic (Co)polycarbonates bearing pendant azido groups0 aSynthesis characterization and UVcrosslinking of aromatic Copoly  cSEP  ae2022010200 v73 a<p>
	A new series of (co)polycarbonates bearing pendent azido groups was synthesized by polycondensation of varying molar proportions of 4, 4'-(5-azidopentane-2, 2-diyl) diphenol and bisphenol-A with triphosgene. The chemical structures, compositions and random nature of (co)polycarbonates were confirmed by NMR spectroscopy. Inherent viscosities and number-average molecular weights of (co)polycarbonates were in the range 0.63-0.77 dL g(-1) and 35,400-43,400 g mol(-1), respectively indicating the formation of reasonably high molecular weight polymers. (Co)polycarbonates could be cast into tough, transparent and flexible films from chloroform solutions. (Co)polycarbonates were further characterized using IR spectroscopy, XRD, TGA and DSC. The thermal crosslinking of (co)polycarbonates bearing pendant azido groups was studied by DSC analysis. Independently, (co)polycarbonates bearing pendant azido groups were exposed to UV irradiation at wavelength of 254 nm and decomposition reaction of azido groups was monitored by FT-IR spectroscopy. The complete decomposition of azido groups was observed with exposure time of 30 min. The formed cross-linked (co)polycarbonates exhibited improved % char yield values compared to parent (co)polycarbonates. The measurement of mechanical properties of representative crosslinked (co)polycarbonates indicated increase in tensile strength and Young's modulus and decrease in % elongation compared to corresponding parent linear (co)polycarbonates.</p>
10aAromatic polycarbonate10aPendant azido group10asolution polycondensation10aTriphosgene10aUV-crosslinking1 aNagane, Samadhan, S.1 aKuhire, Sachin, S.1 aIchake, Amol, B.1 aTalanikar, Aniket, A.1 aLochab, Bimlesh1 aWadgaonkar, Prakash, P.  uhttps://library.ncl.res.in/content/synthesis-characterization-and-uv-crosslinking-aromatic-copolycarbonates-bearing-pendant