화학공학소재연구정보센터
Polymer, Vol.48, No.21, 6254-6261, 2007
Efficient preparation of isotactic polypropylene/montmorillonite nanocomposites by in situ polymerization technique via a combined use of functional surfactant and metallocene catalysis
In order to promote efficiency of the preparation of isotactic polypropylene (i-PP)/montmorillonite (MMT) nanocomposites by in situ polymerization technique, a strategy was laid out to enhance both the intercalative selectivity and the catalyst activity of the in situ polymerization by a combined use of a functional surfactant for MMT modification and a metallocene catalyst system for isospecific propylene polymerization. Thus. (2-hydroxylethyl) hexadecyl diethylammonium iodine was involved in the ion-exchanged organic modification of MMT, leading to an implantation of catalyst-anchoring reactive sites (hydroxyl, OH) in the interlayer galleries of MMT (OMMT). By treating the OH-1-intercalated OMMT successively with excessive methylaluminoxane (MAO) and rac-Me2Si(2-Me-4-Ph-Ind)(2)ZrCl2, the metallocene catalyst typical for i-PP polymerization was stabilized inside the interlayer galleries with a catalytically benign environment. The MMT-borne catalyst, upon further activation by MAO. released fairly high activities for propylene polymerization. The effective intercalative polymerization ensured an efficient preparation of i-PP/MMT nanocomposite. A series of i-PP/MMT nanocomposites containing completely disordered MMT at a loading range of 1.0-6.7 wt% (TGA measurement residue at 600 degrees C were obtained in high yields. (c) 2007 Elsevier Ltd. All rights reserved.