Evidence of Nanoconfinement Effects of MCM-41 on Propylene Polymerization Catalyzed by MCM-41 Supported Metallocene Catalyst in the Presence and Absence of β-Cyclodextrin

Abstract

Propylene polymerization was carried out with MCM-41 supported rac-Et(Ind)2ZrCl2 catalysts, in the presence and absence of beta-cyclodextrin. The resultant PP was studied by X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and differential scanning calorimetry. Through comparison of the results, it was found that the channels of MCM-41 could act as a nanoreactor of propylene polymerization and the polypropylene (PP) contained in the channels had noncrystal structure. However, the PP could grow out of the channels and form some crystals after the active sites on the surface of MCM-41 were destroyed. This showed that the channels of MCM-41 had great confinement effects on propylene polymerization.

Effects of Interconnected Polymer Nanopores Leading to Different Degrees of Confined Polymerization

“…DSC thermograms are shown in Figure . PE catalyzed by PPM‐supported Cp 2 TiCl 2 and TiCl 4 catalysts exhibited higher melting point ( T m1 = 144.1 and 145.4 °C, respectively) compared with that of PE polymerized by PPM‐supported Cp 2 ZrCl 2 ( T m1 = 134.8 °C), homogeneous Cp 2 TiCl 2 ( T m1 = 138.6 °C in Table S1, Supporting Information), and high‐density polyethylene (HDPE: 133—135 °C) . A similar phenomenon of increased melting point was also observed in PE synthesized over metallocene catalysts on MSFs or MCM‐41 .…”

Synthesis of Low Isotactic Polypropylene Using MgCl2/AlCl3-supported Ziegler–Natta Catalysts Prepared Using the One-Pot Milling Method

“…1): grinding the mixture of MgCl 2 and AlCl 3 for 40 h, then adding TiCl 4 into mixture of MgCl 2 and AlCl 3 , followed by grinding for 20 h to obtain the MgCl 2 /AlCl 3 -supported Z-N catalysts. All manipulations were carried out under a dry, oxygen-free argon atmosphere [14,15].…”

Recent research progress in influence of the ansa-zirconcene catalytic system on the polypropylene microstructure

“…As to the effect of aluminate-based co-catalysts on microstructure of polymer, it is generally believed that the catalytic systems with MAO are of higher stereoselectivity than that with other aluminate-based co-catalysts [59,60]. Propene polymerization with Me 2 Si(2-Me-4-tBu-C 5 H 2 ) 2 ZrCl 2 in the presence of excess MAO ([Al]/[Zr] = 2000 : 1) gives highly stereoregular (95-99% mmmm) and regioregular (100% 1,2-insertions) polypropene.…”