02020nas a2200265   4500008004100000022001400041245011100055210006900166260006700235300001400302490000700316520110900323653000601432653002901438653002801467653001301495653001801508653003701526653001901563653000901582100001701591700001501608700001601623856011501639       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<p>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.</p>10a310a4-ethylenedioxythiophene10aheteroaromatic polymers10aPolyurea10apolyurea gels10aThermogravimetric analysis (TGA)10athermoplastics10aWAXS1 aOjha, U., P.1 aRamesh, C.1 aKumar, Anil  uhttp://library.ncl.res.in/content/design-syntheses-and-characterization-new-thermoplastic-polyureas-based-34-002355nas a2200253   4500008004100000022001400041245017200055210006900227260006800296300001200364490000700376520143100383653000901814653002701823653001901850653002201869653000801891653000901899100001101908700001501919700002401934700001501958856012801973       2005                        eng d  a0887-624X00aIn situ polymerization of ethylene with bis(imino)pyridine iron(II) catalysts supported on clay: the synthesis and characterization of polyethylene-clay nanocomposites0 aIn situ polymerization of ethylene with bisiminopyridine ironII   a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcJAN  a304-3180 v433 a<p>Polyethylene-clay nanocomposites were synthesized by in situ polymerization with 2,6-bis[1-(2,6-diisopropylphenylimino)ethyl] pyridine iron(II) dichloride supported on a modified montmorillonite clay pretreated with methylaluminoxane (MAO). The catalysts and the obtained nanocomposites were examined with wide-angle X-ray scattering. The exfoliation of the clay was further established by transmission electron microscopy. Upon the treatment of the clay with MAO, there was an increase in the d-spacing of the clay galleries. No further increase in the d-spacing of the galleries was observed with the iron catalyst supported on the MAO-treated clay. The catalyst activity for ethylene polymerization was independent of the Al/Fe ratio. The exfoliation of the clay inside the polymer matrix depended on various parameters, such as the clay content, catalyst content, and Al/Fe ratio. The crystallinity percentage and crystallite size of the nanocomposites were affected by the degree of exfoliation of the clay. Moreover, when ethylene was polymerized with a mixture of the homogeneous iron(II) catalyst and clay, the degree of exfoliation was significantly lower than when the polymerization was performed with a preformed clay-supported catalyst. This observation suggested that in the supported catalyst, at least some of the active centers resided within the galleries of the clay. (C) 2004 Wiley Periodicals, Inc.</p>10aclay10aIn situ polymerization10aNanocomposites10apolyethylene (PE)10aTEM10aWAXS1 aRay, S1 aGalgali, G1 aLele, Arundhati, C.1 aSivaram, S  uhttp://library.ncl.res.in/content/situ-polymerization-ethylene-bisiminopyridine-ironii-catalysts-supported-clay-synthesis-1