02355nas 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
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.
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