Reactivity of Aluminum-Functionalized Isotactic Polypropylene with Molecular Oxygen

Abstract

ABSTRACT:The efficiency of the synthesis of terminally hydroxylated isotactic polypropylene (i-PP) through the oxidation of Al-functionalized i-PP was evaluated and side-reactions are discussed. Al-functionalized i-PP was prepared by chain-transfer reaction by Et 3 Al with the MgC1 2 -TiC14 -dioctylphthalate1Et3Alldiphenyldimethoxysilane catalyst. It was oxidized by molecular oxygen and poured into methanol for alcoholysis at chain ends. All chain-end groups of the obtained polymer were identified by 13 C NMR and 52 mol% of Al-functionalized chain ends was found converted to hydroxyl groups. 20mol% vinylidene groups by elimination of f$-hydrogen and Smol% vinyl groups by elimination of P-methyl groups were detected. 20mol% of Al-functionalized chain ends remained unreacted. IR analysis of the resulting i-PPs showed the hydroxyl groups at w-ends to form no hydrogen bond and decrease in reaction time with molecular oxygen to lead to lower conversion to terminally hydroxylated chain ends.

Influence of “TMA-depleted” MAO and alkylaluminiums on propylene polymerization at high temperature with TiCl4/MgCl2 catalysts

“…The spectrum of Run 4 showed a number of small irregular peaks. The samples that contained ethylene units would show the peak (38.0 ppm, ␣␥-CH 2 ), the peak (31.0 ppm, ␤␦-CH) and the peak (24.6 ppm, ␤␤-CH 2 ) in the correct 2:2:1 integral ratio [1,14]. Investigation of Kojoh et al [1] and our group [14] showed that the ethylene arose from the degradation of Et 3 Al at 100 • C. It was clear that at Et 3 Al/Ti mole ratio 150 (Run 4) the iPP contained ethylene unit (0.1%, mol%), while at Et 3 Al/Ti mole ratio 25 (Run 2), the iPP contained scarcely ethylene unit.…”

“…It is well known that the industrial polymerization temperature of MgCl 2 -supported Ziegler-Natta catalysts are around 65-80 • C. In recent years, a new supercritical olefin polymerization technology was developed, which needed higher polymerization temperature (more than 90 • C) for propylene polymerization. However, both the activity and the stereospecificity of MgCl 2 -supported Ziegler-Natta catalysts decease when the polymerization temperature rises over 85 • C [1,2]. Kojoh et al [1] and our research group [3] had reported that in the propylene polymerization with MgCl 2 -supported Ziegler-Natta catalysts at 100 • C, the activity obtained with i-Bu 3 Al, which shows a weaker coordination and alkylation than Et 3 Al, was higher than that obtained with Et 3 Al.…”

The discovery and progress of MgCl2‐supported TiCl4 catalysts

“…35 MgCl 2 -supported TiCl 4 catalysts can contribute to it as an example that they were able to provide terminally hydroxylated iso-PP. 36 We believe in a bright future for MgCl 2 -supported TiCl 4 catalysts as well as their brilliant progress.…”

Establishment of De Facto Standard Catalysts in the Polypropylene Industry

“…Functionalized PP is useful to link different polymers to the PP segment because the functional groups can be utilized as chemically reactive groups or intermediates of initiators for polar monomer polymerizations such as living radical, living anion or ring‐opening polymerizations. For example, we have reported chain‐end hydroxylation of PP38 based on our investigation of the chain transfer reaction by trialkyl aluminum 39. These types of functionalized PPs are expected to create novel hybrid materials as well as the PE‐based hybrids, which demonstrated nano‐order self‐assembling morphologies 40–43…”