Zirconocene-MAO catalyzed homo- and copolymerizations of linear asymmetrically substituted dienes with propene: a novel strategy to functional (co)poly(α-olefin)s

Abstract

SUMMARY: The polymerization behavior of three linear asymmetrically substituted dienes, i.e. 6-phenyl-1 ,5-hexadiene (A), 7-methyl-1,6-octadiene (B) and R(+)-5,7-dimethyl-1,6-0ctadiene (isocitronellene, C) is reported in order to study the effect of substitution at one vinylic group. Homopolymerization of these monomers with the catalyst system rac-Et[Ind]2ZrC12/MA0 resulted in no reaction products in the case of monomer A and in polymers with % , = 3.5 kg/mol and % = 14.0 kg/mol with the monomers B and C, respectively. According to NMR analysis, the vinylene end group of isocitronellene remained untouched during polymerization, which excludes the possibility of cyclopolymerization or crosslinking. Copolymerization of isocitronellene with propene resulted in incorporation of the diene (15.6 mol-%) equal to the stoichiometric ratio in the monomer feed, with a relatively high catalyst activity. The degree of incorporated isocitronellene is inversely related to the polymerization temperature, providing control over crystallinity (isotacticity) and molecular weight of the copolymer. The isocitronellene homo-and copolymers could be epoxidized quantitatively and brominated to an extent of 90%. Perfluorohexyl iodide was grafted onto the isocitronellene/propene copolymer by radical reaction (conversion 80%), yielding a poly(a-olefin) with fluorinated side chains.

Copolymerization of Ethylene and 1,7-Octadiene, 1,9-Decadiene with Zirconocene Catalysts

“…Copolymerization of common olefins, such as ethylene and propylene, and nonconjugated diene with metallocene catalyst has been one of the useful methods to synthesize polyolefins having unique structures. [1,2] Three types of propagation reactions of a,onon-conjugated diene are possible in copolymerization with ethylene or a-olefin as shown in Scheme 1. The first is a 1,2-addition-type propagation reaction, leaving pendent vinyl groups in the resulting polymers.…”

Functionalisation of Polyolefins: Grafting of Phenol Groups on Olefin/5,7‐Dimethylocta‐1,6‐diene Copolymers

“…One of the most developed modification processes consists in the hydroboration of the pending double bonds, followed by oxidation to hydroxyl groups. [1][2][3][4] Other reported polymer modification processes of pending unsaturations include: epoxidation, [3][4][5][6][7][8][9] bromination, [5] hydroxylation, [10] sulfonation, [11] oxidation to aldehyde and carboxylic acid functions [7,12] and hydrosilylation. [13,14] Generally, transposing organic chemistry procedures to polymer modifications is not straightforward.…”

Copolymerization of Propene and 5‐Vinyl‐2‐Norbornene: A Simple Route to Polar Poly(propylene)s

“…[13][14][15][16][17] One method to circumvent this problem is the copolymerization of an olefin with a bifunctional comonomer where one of the functional groups is inert toward the catalyst but can subsequently undergo various functionalization reactions during postpolymerization processes. Examples are the polymerizations of ethene or propene with asymmetrically substituted a,o-dienes; [18][19][20][21][22][23] for instance, some time ago we reported the copolymerization of propene with 7-methyl-1,6-octadiene and described several methods to functionalize the resulting copolymers. [24] The copolymerization of ethene with the bicyclic, non-conjugated diene 5-vinyl-2-norbornene (VNB) was reported independently by Marathe [25] and by Pakkanen [26] using Cp 2 ZrCl 2 /MAO and Ph 2 C(Flu)(Cp)ZrCl 2 /MAO, respectively.…”