02021nas a2200265 4500008004100000022001400041245011100055210006900166260006700235300001400302490000700316520110900323653000601432653002901438653002801467653001301495653001801508653003701526653001901563653000901582100001701591700001501608700001601623856011601639 2005 eng d a0887-624X00aDesign, syntheses, and characterization of new thermoplastic polyureas based on 3,4-ethylenedioxythiophene0 aDesign syntheses and characterization of new thermoplastic polyu a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcDEC a5823-58300 v433 a

New thermoplastic polyureas labeled PUn (n = 2, 3, 4, 6, 7, 9, or 10), based on 3,4-ethylenedioxythiophene (EDOT) with flexible aliphatic spacers, were synthesized and characterized for the first time. EDOT was chosen as a replacement for the aromatic phenyl group in conventional thermoplastics based on urea linkages to improve solubility without compromising the thermal properties. As synthesized, all the samples exhibited a semicrystalline nature. The glass-transition and melting temperatures showed a strong dependence on the spacer length. A comparison of the thermal properties of these polyureas with the corresponding phenyl analogues indicated that EDOT was a viable heteroatomic analogue of the phenyl group to be inserted into the main-chain polyureas without hampering their thermal stability. The polyureas with spacer lengths greater than hexamethylene formed transparent gels in N-methylpyrrolidone, 1,1,2,2-tetrachloroethane, and dimethyl sulfoxide. The molecular packing of the polyureas was assigned with wide-angle X-ray diffraction studies. (c) 2005 Wiley Periodicals, Inc.

10a310a4-ethylenedioxythiophene10aheteroaromatic polymers10aPolyurea10apolyurea gels10aThermogravimetric analysis (TGA)10athermoplastics10aWAXS1 aOjha, U., P.1 aRamesh, C.1 aKumar, Anil uhttps://library.ncl.res.in/content/design-syntheses-and-characterization-new-thermoplastic-polyureas-based-34-001768nas a2200169 4500008004100000022001400041245013500055210006900190260009200259300001200351490000700363520104900370100002001419700001501439700001601454856012801470 2005 eng d a0267-829200aEffect of connectivity and terminal functionality on mesophase behaviour of thermotropic liquid crystals containing biphenyl units0 aEffect of connectivity and terminal functionality on mesophase b a4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLANDbTAYLOR & FRANCIS LTDcAPR a499-5120 v323 a

A series of 4,4'-disubstituted biphenyls, designated as series HBC, in which, one substituent is an ester group linked directly to the ring and the other is the hydroxy-containing group O(CH2)(n)OH, have been prepared and analysed by differential scanning Calorimetry, polarizing optical microscopy and X-ray diffraction. The introduction of a trimethylene unit between the ester functional group and the biphenyl moiety of the HBC series gives rise to the HBB series, which did not exhibit liquid crystalline behaviour. Interestingly, mesophase behaviour could be restored by replacing the methylene group ( of the trimethylene unit) that was directly attached to the biphenyl ring by a keto group (HBOB series). When the terminal hydroxy group of these three series was substituted by a group such as acetoxy or hydrogen, the transition temperatures were reduced, and the disappearance of mesophase behaviour was observed in some cases. However, this could be recovered by the replacement of the ester group by a carboxylic acid group.

1 aRanganathan, T.1 aRamesh, C.1 aKumar, Anil uhttps://library.ncl.res.in/content/effect-connectivity-and-terminal-functionality-mesophase-behaviour-thermotropic-liquid-002086nas a2200229 4500008004100000022001400041245016400055210006900219260006800288300001400356490000700370520120800377653001001585653003201595653001801627653001601645100002001661700001701681700001501698700001601713856012701729 2005 eng d a0887-624X00aMain chain thermotropic liquid crystalline polyurethanes containing biphenyl mesogens based on novel AB-type self-polycondensation route: FT-IR and XRD studies0 aMain chain thermotropic liquid crystalline polyurethanes contain a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcMAY a1903-19120 v433 a

The detailed mesophasic characterization of main chain liquid crystalline polyurethanes containing biphenyl mesogen, which were synthesized by the novel AB-type self-polycondensation approach, was carried out by using Differential Scanning Calorimetry (DSC), Polarized Optical Microscopy (POM), variable temperature X-ray Diffraction (XRD), and Fourier Transform Infrared (FT-IR) spectroscopic studies. The type of mesophase present in these polymers was identified to be the smectic A phase by POM and XRD studies. The smectic layer thickness was found to increase as the length of the spacer increased. The effect of temperature on the hydrogen bonding was analyzed by FT-IR studies. The curve-fitting analysis of the NH stretching and C=O stretching modes of vibrations indicated a gradual decrease in hydrogen bonding during the transition from the crystalline state to the mesophase. The mesophase to isotropic liquid transition was then accompanied by the complete disappearance of the hydrogen bonding. The biphenyl bands also showed changes during phase transitions due to the coupling of biphenyl vibration modes with the urethane linkage attached to it. (c) 2005 Wiley Periodicals, Inc.

10aFT-IR10aliquid-crystalline polymers10apolyurethanes10aXRD studies1 aRanganathan, T.1 aGowd, E., B.1 aRamesh, C.1 aKumar, Anil uhttps://library.ncl.res.in/content/main-chain-thermotropic-liquid-crystalline-polyurethanes-containing-biphenyl-mesogens-001630nas a2200157 4500008004100000022001400041245013300055210006900188260007100257300001200328490000700340520096900347100001701316700001501333856012401348 2005 eng d a0024-929700aStudies on the crystallization behavior of nylon-6 in the presence of layered silicates using variable temperature WAXS and FTIR0 aStudies on the crystallization behavior of nylon6 in the presenc a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJAN a454-4620 v383 a

The crystallization of nylon-6 clay nanocomposite was studied by variable temperature wide-angle X-ray scattering (WAXS) and Fourier transform infrared spectroscopy (FTIR). Nylon-6 was found to crystallize into gamma phase at 210 degreesC, as indicated by its characteristic peaks in WAXS. However, an additional peak was observed close but on the lower angle side of the main gamma phase peak, indicating the presence of a metastable phase. The extent of metastable phase that developed was dictated by the clay content in the nanocomposite as well as the crystallization conditions. The temperature dependence of the d spacing of the gamma phase obtained in the presence of clay layers showed difference from the gamma phase obtained by treating nylon-6 in KI/I-2 solution. Variable temperature FTIR studies were conducted on the gamma phases for the first time, and it showed definite differences in the spectra of the phases obtained by the two methods.

1 aNair, S., S.1 aRamesh, C. uhttps://library.ncl.res.in/content/studies-crystallization-behavior-nylon-6-presence-layered-silicates-using-variable-001970nas a2200169 4500008004100000022001400041245006800055210006600123260007100189300001400260490000700274520137000281100001701651700001501668700001601683856010101699 2006 eng d a0024-929700aCrystalline phases in nylon-11: studies using HTWAXS and HTFTIR0 aCrystalline phases in nylon11 studies using HTWAXS and HTFTIR a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAPR a2841-28480 v393 a

Nylon-11 was crystallized into different crystalline phases by appropriate methods. The chance in the structure during heating was monitored in situ by wide-angle X-ray scattering (WAXS). The alpha phase obtained by precipitating nylon-11 in 1,4-butanediol started transforming into the pseudohexagonal phase on heating, but the transformation was not fully completed before melting. The melt crystallized sample at 175 degrees C gave the pseudohexagonal phase, which transformed into the alpha' phase on cooling to room temperature at about 100 degrees C. The d spacing of the 00 1 reflection also showed a change at the transition temperature. The melt-quenched sample showed the pseudohexagonal phase, which did not change during heating, but on cooling transformed into alpha' phase. The gamma phase was obtained by casting nylon-11 in trifluoroacetic acid (TFA), and it changed into the pscudohexagonal phase at about 110 degrees C on heating. The d spacing of the 001 reflection depended on the way in which it was obtained. The studies have shown that nylon-11 is one of the few nylons that exhibit an extensive degree of polymorphism. High-temperature Fourier transform infrared spectroscopy (HTFTIR) studies revealed, apart from the conformational differences between various phases of nylon-11, some information on the formation of the gamma phase.

1 aNair, S., S.1 aRamesh, C.1 aTashiro, K. uhttps://library.ncl.res.in/content/crystalline-phases-nylon-11-studies-using-htwaxs-and-htftir-000673nas a2200157 4500008004100000022001400041245011100055210006900166260007100235300001400306490000700320100001900327700002500346700001500371856012900386 2006 eng d a0024-929700aPreparation and characterization of sulfonated syndiotactic polystyrene ionomers/organoclay nanocomposites0 aPreparation and characterization of sulfonated syndiotactic poly a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcOCT a7199-72030 v391 aGovindaiah, P.1 aMallikarjuna, S., R.1 aRamesh, C. uhttps://library.ncl.res.in/content/preparation-and-characterization-sulfonated-syndiotactic-polystyrene-ionomersorganoclay-002139nas a2200205 4500008004100000022001400041245026000055210006900315260007300384300001400457490000700471520119000478653001601668653002101684653002701705653003401732100002001766700001501786856013201801 2006 eng d a1381-514800aSynthesis and characterization of main chain thermotropic liquid crystalline polyesters based on methyl 4-[4 `-(omega-hydroxyalkoxy)blphenyl-4-yl]-4-oxobutyrate: Effects of keto group and connectivity on mesophasic characteristics of biphenyl based AB-typ0 aSynthesis and characterization of main chain thermotropic liquid aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcOCT a1003-10130 v663 a

A series of biphenyl based main chain thermotropic liquid crystalline polyesters, poly(hydroxyalkoxybiphenyl oxobutyrate) [PRBOB-2,n (n = 2-8)], containing various methylene spacers was synthesized by using the novel AB-type self-polycondensation route from the monomers, methyl 4-[4'-(omega-hydroxyalkoxy)biphenyl-4-yl]-4-oxobutyrate (HBOB-2,n). The mesophase characteristics of these polyesters was studied using DSC, polarized light optical microscopy and XRD techniques. The transition temperatures were found to decrease upon increasing the spacer length with an even polymer exhibiting higher transition temperature than the odd counterpart. The mesophase type also indicated an odd-even oscillation with the even members showing normal smectic phase and odd members exhibiting tilted smectic phase. The comparison of mesophasic characteristics of these polyesters with that of structurally similar AB-type polyesters indicated that the total number of atoms connecting the mesogen in a polymeric repeat unit governs the nature of the mesophase while the rigidity of the system dictates the magnitude of transition temperatures. (c) 2006 Elsevier B.V. All rights reserved.

10aAB approach10abiphenyl mesogen10aeffect of connectivity10aLiquid crystalline polyesters1 aRanganathan, T.1 aRamesh, C. uhttps://library.ncl.res.in/content/synthesis-and-characterization-main-chain-thermotropic-liquid-crystalline-polyesters-based-102362nas a2200169 4500008004100000022001400041245017000055210006900225260007100294300001400365490000700379520162400386100002002010700001502030700001602045856013102061 2007 eng d a0024-929700aCopolyesters based on poly(butylene terephthalate)s containing cyclohexyl and cyclopentyl ring: Effect of molecular structure on thermal and crystallization behavior0 aCopolyesters based on polybutylene terephthalates containing cyc a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcSEP a6906-69150 v403 a

In an effort to understand the role of molecular structure on the thermal properties of polyesters and copolyesters, the following polyesters were synthesized: poly(1,4-cyclohexane dimethylene terephthalate) (PCT), poly(butylene-1,4-cyclohexane dicarboxylate) (PBCD), poly (1,3-cyclopentane dimethylene terephthalate) (PCPDT), and poly(butylene-1,3-cyclopentane dicarboxylate) (PBCP). PCT and PCPDT are semicrystalline polymers with crystallization and melting temperatures higher than poly(butylene terephthalate) (PBT). However, PBCD and PBCP have lower glass transition temperature than PBT. From these homopolymers a series of poly(butylene-co-1,4-cyclohexane dimethylene terephthalate) (P(BT-co-CT )), poly(butylene terephthalate-co-1,4cyclohexane dicarboxylate) (P(BT-co-BCD)), poly(butylene-co-1,3-cyclopentylene dimethylene) (P(BT-co-CPDT)), and poly(butylene terephthalate-co-1,3-cyclopentane dicarboyxlate) (P(BT-co-PBCP)) random copolyesters were synthesized for the first time, and their cocrystallization behavior was investigated using differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD). The copolymers were found to be statistically random and crystallized in all compositions. The P(BT-co-CT) and (P(BT-co-CPDT) copolyesters exhibited typical eutectic behavior in melting and crystallization, which indicated isodimorphic cocrystallization behavior. On the other hand, in the case of P(BT-co-BCD) and P(BT-co-PBCP) copolymers, the melting and crystallization temperatures showed linear dependency with composition, indicating isomorphic-like crystallization behavior.

1 aSandhya, T., E.1 aRamesh, C.1 aSivaram, S. uhttps://library.ncl.res.in/content/copolyesters-based-polybutylene-terephthalates-containing-cyclohexyl-and-cyclopentyl-ring-002066nas a2200169 4500008004100000022001400041245012000055210006900175260007100244300001400315490000700329520138100336100001601717700001901733700001501752856012901767 2008 eng d a0024-929700aRole of solvent molecules as a trigger for the crystal phase transition of syndiotactic polystyrene/solvent complex0 aRole of solvent molecules as a trigger for the crystal phase tra a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcDEC a9814-98180 v413 a

The phase transitions occurring in the syndiotactic polystyrene-norbornadiene complex were investigated by simultaneous measurements of wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). To understand the effect of norbornadiene molecules on the phase-transition behavior, the delta form samples with different contents of norbornadiene were prepared. By heating these samples, we found that the delta-to-gamma transition occurred well below 100 degrees C in a broad temperature range, and the onset of the transition temperature depended on the content of norbornadiene included in the starting sample. The sample without norbornadiene molecules showed the delta-to-gamma transition to be above 100 degrees C. Upon further heating, the gamma form transformed into a mixture of alpha and beta forms in the presence of norbornadiene molecules, whereas the sample without norbornadiene transformed into only the alpha form. In this way, it has been found that the solvent molecules, which are not completely evaporated from the sample but are transiently trapped in the amorphous region because of the slow diffusion, have a significant role in facilitating the phase transitions as well as the transition temperatures in the crystalline region. On the basis of WAXD and DSC results, a phase-transition model has been reasonably constructed.

1 aGowd, Bhoje1 aTashiro, Kohji1 aRamesh, C. uhttps://library.ncl.res.in/content/role-solvent-molecules-trigger-crystal-phase-transition-syndiotactic-polystyrenesolvent-001569nas a2200241 4500008004100000022001400041245006100055210006100116260010600177300001200283490000700295520074200302653002201044653001301066653002101079653001701100653003601117653002901153100001601182700001901198700001501217856009501232 2009 eng d a0079-670000aStructural phase transitions of syndiotactic polystyrene0 aStructural phase transitions of syndiotactic polystyrene aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcMAR a280-3150 v343 a

Syndiotactic polystyrene (sPS) exhibits four crystal modifications (alpha, beta, gamma, and delta), along with intermediate forms with different molecular conformations, as well as different chain-packing structures. The extensive literature on the crystal structures exhibited by sPS is reviewed herein, including, the mechanisms of phenomena such as solvent-induced crystallization, thermally induced crystallization and gelation, and the phase transitions among the various crystalline forms. The latter have been studied by static and dynamic wide-angle and small-angle X-ray scattering, infrared and Raman spectra, and neutron scattering, etc., in addition to computer simulations. (C) 2009 Elsevier Ltd. All rights reserved.

10acrystal structure10aGelation10aphase transition10apolymorphism10aSolvent-induced crystallization10aSyndiotactic polystyrene1 aGowd, Bhoje1 aTashiro, Kohji1 aRamesh, C. uhttps://library.ncl.res.in/content/structural-phase-transitions-syndiotactic-polystyrene-002029nas a2200253 4500008004100000022001400041245008500055210006900140260009200209300001000301490000800311520115200319653001201471653001601483653001401499653001401513653001401527100002401541700003101565700001501596700002701611700002101638856011601659 2013 eng d a0040-500000aStructure-property relationship of different types of polyester industrial yarns0 aStructureproperty relationship of different types of polyester i a4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLANDbTAYLOR & FRANCIS LTDcJAN a35-450 v1043 a

Four major types of polyester industrial yarns (1000 Denier) which are used commercially were studied for their key structural parameters. An attempt has been made to establish a relationship between morphology and properties of these yarns. High tenacity (HT) polyester yarn has the highest birefringence, amorphous orientation, and long period but is relatively less crystalline. High shrinkage characteristic of HT polyester yarn can be accounted for its higher amorphous orientation. High modulus low shrinkage (HMLS) polyester yarn has higher crystallinity and crystal size compared to HT yarn. Fraction of tie molecules of these yarns has been calculated and found that low shrinkage (LS) and super low shrinkage (SLS) yarns have lesser tie molecules. These LS and SLS yarns are tailor-made to achieve lower shrinkage and at the same time maintaining a good level of tenacity. This is achieved with lower amorphous orientation in the final drawn yarn structure. Amorphous orientation was found to have stronger influence than any other structural parameter on the key yarn properties like modulus, tenacity, elongation, and shrinkage.

10amodulus10aorientation10apolyester10ashrinkage10astructure1 aSamui, Barun, Kumar1 aPrakasan, Manikanda, Priya1 aRamesh, C.1 aChakrabarty, Debabrata1 aMukhopadhyay, R. uhttps://library.ncl.res.in/content/structure-property-relationship-different-types-polyester-industrial-yarns-002059nas a2200265 4500008004100000022001400041245009800055210006900153260009400222300001400316490000800330520114900338653001001487653001201497653001401509653001401523653001401537653001401551100002401565700002101589700002101610700001501631700002701646856012001673 2016 eng d a0040-500000aStudies on the static and dynamic properties of different types of polyester industrial yarns0 aStudies on the static and dynamic properties of different types  a2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLANDbTAYLOR & FRANCIS LTDcOCT a1175-11840 v1073 a

Four major types of polyester industrial yarns, viz. high tenacity (HT), high modulus low shrinkage (HMLS), low shrinkage (LS) and super low shrinkage (SLS) polyester yarns, were studied for their static and dynamic properties. An attempt has been made to establish a linkage between static and dynamic properties of these yarns with its structure and with its end applications. HMLS and HT polyester yarns have lower tan delta and work loss, which are the desired characteristics required for its end applications which include tire and conveyer belt. Higher overall orientation and higher fraction of tie molecules helped to achieve these properties in HT and HMLS polyester yarns. LS and SLS polyester yarns are mostly used for static applications. Low thermal shrinkage is the key requirement for the downstream processes of these yarns. Lower amorphous orientation in these two yarns is primarily responsible for achieving very low thermal shrinkage. A good co-relation has been established between the peak temperature of work loss (in slow speed hysteresis test) and the peak temperature of tan delta (in high-speed dynamic test).

10acreep10amodulus10apolyester10ashrinkage10atan delta10awork loss1 aSamui, Barun, Kumar1 aDasgupta, Saikat1 aMukhopadhyay, R.1 aRamesh, C.1 aChakrabarty, Debabrata uhttps://library.ncl.res.in/content/studies-static-and-dynamic-properties-different-types-polyester-industrial-yarns01774nas a2200169 4500008004100000245011600041210006900157260000800226300002200234490000800256520113900264100002001403700002401423700001501447700002001462856012201482 2019 eng d00aBorassus powder-reinforced poly(lactic acid) composites with improved crystallization and mechanical properties0 aBorassus powderreinforced polylactic acid composites with improv cJAN aArticle No: 474400 v1363 aThis article reports on the development of biocomposites based on polylactic acid (PLA) and borassus powder. Borassus powder was treated with alkali to remove hemicelluloses and lignin. The treated borassus improved the homogeneous mixing with PLA and increased the crystallinity of PLA. Dispersibility of the borassus was studied by scanning electron microscopy (SEM) and X‐ray MicroCT. PLA/borassus composites were prepared by melt mixing of PLA with 5, 10, and 15 wt % treated/untreated borassus. Composites were examined for mechanical properties and crystallization. Composites showed enhanced tensile strength compared to neat PLA. The PLA/treated borassus powder composites displayed higher crystallinity than PLA. The isothermal cold crystallization study showed increase in the crystallization rate of PLA in the presence of treated borassus. The spherulitic growth was studied using polarized optical microscopy. The enhanced performance of the PLA‐borassus composites was observed in the presence of borassus. This study demonstrates that the PLA‐borassus composites show great promise for bioplastics applications.1 aMarathe, Y., N.1 aArun, Torris, A. T.1 aRamesh, C.1 aBadiger, M., V. uhttps://library.ncl.res.in/content/borassus-powder-reinforced-polylactic-acid-composites-improved-crystallization-and