01896nas a2200229 4500008004100000022001400041245008700055210006900142260006800211300001400279490000800293520106100301653002701362653002101389653001701410100002201427700002801449700003101477700001801508700001901526856012101545 2006 eng d a0021-899500aThermotropic behavior of lithocholic acid derivative linked hydroxyethyl cellulose0 aThermotropic behavior of lithocholic acid derivative linked hydr a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcMAY a1995-20010 v1003 a

Various mesogenic lithocholic acid (LA) derivatives [3-acetyl LA (LAAC); 3-propionyl LA (LAP), 3-cinnamoyl LA (LACin); 3-benzoyl LA (LAB), 3-(4-nitrobenzoyl) LA (LANB); and methyl-3-(3-carboxypropionyl) LA, i.e., LA methyl ester monosuccinate (LAMeMS)] were reacted with hydroxyethyl cellulose (HEC) to obtain a series of LA derivatives of HEC. These polymers were characterized by the mesogen content, 1.1, differential scanning calorimetry, and hot-stage coupled polarizing optical microscopy. The degree Of Substitution (DS) ranged from 0.27 to 1.11. Polymers HEC-LAB (DS = 1.11), HEC-LANB (DS = 0.80), HEC-LACin (DS = 0.76), and HEC-LAP (DS = 0.27) exhibited a mesophase on heating whereas HEC-LAB also showed a mesophase on cooling. The other polymers HEC-LAAC (DS = 0.89) and HEC-LAMeMS (DS = 0.36) did not reveal mesophase formation with either heating or cooling. It is observed that the formation of a mesophase is affected by the type of mesogen that is used rather than the mesogen content of the polymer. (c) 2006 Wiley Periodicals, Inc.

10ahydroxyethyl cellulose10alithocholic acid10athermotropic1 aShaikh, V., A. E.1 aMaldar, Noormahamad, N.1 aLonikar, Shrikant, Vitthal1 aRajan, C., R.1 aPonrathnam, S. uhttps://library.ncl.res.in/content/thermotropic-behavior-lithocholic-acid-derivative-linked-hydroxyethyl-cellulose-102761nas a2200253 4500008004100000245011300041210006900154260000800223300001400231490000600245520182500251653001602076653001802092653003802110653002502148653003202173653002502205653004502230653003202275653001702307653003302324100001902357856013102376 2011 eng d00aSynthesis and characterization of cholesteric thermotropic liquid crystalline polyesters based on isosorbide0 aSynthesis and characterization of cholesteric thermotropic liqui cOCT a1520-15270 v23 a

Generally main chain cholesteric thermotropic liquid crystalline polymers are prepared form chiral dia-cid or diol monomer. But these monomers are costly. Isosorbide is chiral cycloaliphatic diol accessible from renewable resources in the form of pure enantiomers. Thus it is used to synthesize main chain cholesteric thermotropic liquid crystalline polymers. Incorporation of phenyl hydroquinone into the backbone of the main chain frustrates chain pack-ing, thus lowering the crystallinity and depressing the melting point below the degradation temperature, also improves the solubility due to disruption of packing and maintains the mechanical and thermal performance. Results: Optical microscopy study reveals that more than 50% of isosorbide content with phenyl hydroquinone and terephthalic acid showed “yellow iridescent oily streaks” with a background of mosaic/marble texture. These are the typical textures of cholesteric liquid crystalline phase. Copolyesters based on phenyl hydroquinone, isosorbide and terephthalic acid are soluble in aprotic solvents like N,N-dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), and N-methyl-2-pyrrolidone (NMP). Solubility increases with the content of isosorbide percent. Thermal stabil-ity of all copolyesters was more than 300˚C on the basis of 10 wt% loss. Conclusions: It was found that main chain cholesteric thermotropic liquid crystalline polymers can be prepared form chiral cycloaliphatic diol such as isosorbide. Main chain cholesteric thermotropic liquid crystalline polyesters are prepared from phenyl hydroquinone, isosorbide and terephthalic acid showed thermal stability more than 300˚C. Main chain cholesteric thermotropic liquid crystalline polymers are soluble in aprotic solvents like DMAC, DMSO, DMF and NMP

10aCholesteric10aCrystallinity10adifferential scanning calorimetry10aInherent Viscosity10aLiquid Crystalline Polymers10aOptical Microscopy10aSolubility and Solution Polycondensation10aThermo Gravimetric Analysis10athermotropic10aWide Angle X-Ray Diffraction1 aChavan, Nayaku uhttps://library.ncl.res.in/content/synthesis-and-characterization-cholesteric-thermotropic-liquid-crystalline-polyesters-based01880nas a2200241 4500008004100000022001400041245014900055210006900204260010200273300001400375490000700389520088200396653003101278653003301309653003401342653001501376653001701391100002901408700003101437700002301468700001901491856012801510 2015 eng d a0250-470700aThermotropic liquid crystalline polyesters derived from bis-(4-hydroxybenzoyloxy)-2-methyl-1,4-benzene and aliphatic dicarboxylic acid chlorides0 aThermotropic liquid crystalline polyesters derived from bis4hydr aC V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIAbINDIAN ACAD SCIENCEScSEP a1301-13080 v383 a

A series of thermotropic liquid crystalline polyesters derived from bis-(4-hydroxybenzoyloxy)-2-methyl-1,4-benzene(BHBOMB) and aliphatic dicarboxylic acid chlorides were investigated. All these polyesters were synthesized by interfacial polycondensation method and characterized by differential scanning calorimetry and wide-angle X-ray diffractometer. These polyesters consist of BHBOMB as a mesogenic diol and aliphatic diacid chlorides were used as flexible spacers. The length of oligomethylene units in polymer was varied from the trimethylene to the dodecamethylene groups. The transition temperatures and thermodynamic properties were studied for all these polymers. All these polyesters were soluble in chlorinated solvents such as chloroform, dichloromethane, dichloroethane, etc. More importantly, all these polyesters exhibited very large mesophase stability.

10adicarboxylic acid chloride10ainterfacial polycondensation10aLiquid crystalline polyesters10arigid diol10athermotropic1 aMulani, Khudbudin, Baban1 aMomin, Mohasin, Shamshuddi1 aGanjave, Nitin, V.1 aChavan, Nayaku uhttps://library.ncl.res.in/content/thermotropic-liquid-crystalline-polyesters-derived-bis-4-hydroxybenzoyloxy-2-methyl-14-0