01893nas a2200241   4500008004100000022001400041245011500055210006900170260009900239300001400338490000700352520094900359653003801308653002401346653002001370653001401390653001801404100003101422700002101453700002401474700002501498856012801523       2010                        eng d  a0266-353800aExfoliation of clay layers in polypropylene matrix using potassium succinate-g-polypropylene as compatibilizer0 aExfoliation of clay layers in polypropylene matrix using potassi  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcSEP  a1550-15560 v703 a<p>The efficiency of potassium succinate-g-polypropylene (KPPSA) as compatibilizer for the dispersion of clay in a high molecular weight polypropylene during melt mixing for the preparation of nanocomposites was evaluated and compared with maleic anhydride-g-polypropylene (PPMA). Nanocomposites were prepared by direct melt mixing and by masterbatch methods and the structure obtained was characterized by WAXD and TEM. The exfoliation and better dispersion of the organoclay was observed with KPPSA than PPMA. The dispersion of clay was found to be dependent on the method of preparation, type and the amount of compatibilizer used. The dispersion was better when the nanocomposites were prepared by two step masterbatch route than the single step direct mixing method. Flexural moduli and crystallization behavior were studied and correlated with the dispersion of organoclay in the PP matrix. (C) 2010 Elsevier Ltd. All rights reserved.</p>10adifferential scanning calorimetry10aMechanical property10aNano composites10aNanoclays10apolypropylene1 aRama, Mallikarjuna, Shroff1 aNeppalli, Ramesh1 aChellaswamy, Ramesh1 aSwaminathan, Sivaram  uhttps://library.ncl.res.in/content/exfoliation-clay-layers-polypropylene-matrix-using-potassium-succinate-g-polypropylene-002761nas 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<p>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</p>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-based02592nas a2200277   4500008004100000022001400041245008800055210006900143260007300212300001200285490000900297520161200306653001701918653003801935653002201973653002101995653002102016653002002037100002502057700002002082700002602102700002402128700002102152700002502173856011602198       2013                        eng d  a1570-963900aPolyproline fold-In imparting kinetic stability to an alkaline serine endopeptidase0 aPolyproline foldIn imparting kinetic stability to an alkaline se  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR  a708-7160 v18343 a<p>Polyproline II (PPII) fold, an unusual structural element was detected in the serine protease from Nocardiopsis sp. NCIM 5124 (NprotI) based on far UV circular dichroism spectrum, structural transitions of the enzyme in presence of GdnHCl and a distinct isodichroic point in chemical and thermal denaturation. The functional activity and conformational transitions of the enzyme were studied under various denaturing conditions. Enzymatic activity of NprotI was stable in the vicinity of GdnHCl upto 6.0 M concentration, organic solvents viz, methanol, ethanol, propanol (all 90% v/v), acetonitrile (75% v/v) and proteases such as trypsin, chymottypsin and proteinase K (NprotI:protease 10:1). NprotI seems to be a kinetically stable protease with a high energy barrier between folded and unfolded states. Also, an enhancement in the activity of the enzyme was observed in 1 M GdnHCl upto 8 h, in organic solvents (75% v/v) for 72 h and in presence of proteolytic enzymes. The polyproline fold remained unaltered or became more prominent under the above mentioned conditions. However, it diminished gradually during thermal denaturation above 60 degrees C. Thermal transition studies by differential scanning calorimetry (DSC) showed scan rate dependence as well as irreversibility of denaturation, the properties characteristic of kinetically stable proteins. This is the first report of PPII helix being the global conformation of a non structural protein, an alkaline serine protease, from a microbial source, imparting kinetic stability to the protein. (C) 2013 Elsevier B.V. All rights reserved.</p>10aConformation10adifferential scanning calorimetry10aKinetic stability10aNocardiopsis sp.10aPolyproline fold10aSerine protease1 aRohamare, Sonali, B.1 aDixit, Vaishali1 aNareddy, Pavan, Kumar1 aSivaramakrishna, D.1 aSwamy, Musti, J.1 aGaikwad, Sushama, M.  uhttps://library.ncl.res.in/content/polyproline-fold-imparting-kinetic-stability-alkaline-serine-endopeptidase-002096nas a2200229   4500008004100000022001400041245020100055210006900256260006700325490000800392520112200400653001801522653001501540653003801555653002601593653003201619100002201651700002401673700002301697700002501720856012101745       2016                        eng d  a0021-899500aSynthesis and characterization of well-defined random and block copolymers of epsilon-caprolactone with l-lactide as an additive for toughening polylactide: Influence of the molecular architecture0 aSynthesis and characterization of welldefined random and block c  a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcAPR0 v1333 a<p>Well-defined multiarmed star random and block copolymers of epsilon-caprolactone with l-lactide with controlled molecular weights, low polydispersities, and precise numbers of arms were synthesized by the ring-opening polymerization of respective cyclic ester monomers. The polymers were characterized by H-1-NMR and C-13-NMR to determine their chemical composition, molecular structure, degree of randomness, and proof of block copolymer formation. Gel permeation chromatography was used to establish the degree of branching. Star-branched random copolymers exhibited lower glass-transition temperatures (T-g's) compared to a linear random copolymer. When the star random copolymers were melt-blended with poly(l-lactic acid) (PLA), we observed that the elongation of the blend increased with the number of arms of the copolymer. Six-armed block copolymers, which exhibited higher T-g's, caused the maximum improvement in elongation. In all cases, improvements in the elongation were achieved with no loss of stiffness in the PLA blends. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43267.</p>10abiodegradable10acopolymers10adifferential scanning calorimetry10amechanical properties10aring-opening polymerization1 aDeokar, Megha, D.1 aIdage, Susheela, B.1 aIdage, Bhaskar, B.1 aSivaram, Swaminathan  uhttps://library.ncl.res.in/content/synthesis-and-characterization-well-defined-random-and-block-copolymers-epsilon-0