Synthesis of Amorphous Ethylene Copolymers with 2-Vinylnaphthalene, 4-Vinylbiphenyl and 1-(4-Vinylphenyl)naphthalene

Abstract

Ethylene copolymerization with 2-vinylnaphthalene (VN) by ( t BuC 5 H 4 )TiCl 2 (O-2,6-i Pr 2 C 6 H 3 ) (1)−MAO catalyst system afforded high-molecular-weight amorphous copolymers with unimodal molecular weight distributions as well as uniform compositions (M n = 18 100−39 900, M w /M n = 1.23−1.47, T g = 24−75 °C, VN 21.6−44.8 mol %). Copolymerization with 4vinylbiphenyl (VB) using 1− and (1,2,4-Me 3 C 5 H 2 )TiCl 2 (O-2,6-i Pr 2 C 6 H 3 ) (2)−MAO catalyst systems also yielded highmolecular-weight copolymers (M n = 96 200−222 000, M w /M n = 1.33−2.06), and synthesis of the copolymers with high VB contents (>50 mol %) has been demonstrated. These copolymerizations in the presence of a [Me 2 Si(C 5 Me 4 )(N t Bu)]TiCl 2 (4)−MAO catalyst system afforded semicrystalline polymers (possessing melting temperatures of 91−103 °C). Linear relationships between the glass transition temperature (T g ) and the comonomer (VN, VB) content have been demonstrated. The T g values in the same comonomer content increased in the order VN > VB > styrene, suggesting that introduction of an aromatic substituent to the side pendent group affects the thermal properties (T g values). These copolymers possess resonances ascribed to repeated VN (VB) incorporations on the basis of microstructural analysis of poly(ethylene-co-VN)s and poly(ethylene-co-VB)s through 13 C nuclear magnetic resonance (NMR) spectra, and the regioselectivity as well as the degree of the head-to-tail repeated insertions is affected by the cyclopentadienyl fragment and the comonomer (VN, VB, styrene) employed. Synthesis of high-molecular-weight amorphous poly(ethylene-co-VB) with high VB content, which possesses high T g with a uniform composition (M n = 130 000, M w /M n = 1.51, T g = 156 °C, VB 87.5 mol %), has thus been attained by copolymerization using the 2−MAO catalyst system.

Ethylene/Myrcene Copolymers as New Bio-Based Elastomers Prepared by Coordination Polymerization Using Titanium Catalysts

“…Table summarizes the results for ethylene copolymerizations with myrcene (My) using various half-titanocene ( 1 – 4 , Chart )–MAO catalyst systems. The phenoxide- or ketimide-modified half-titanocenes shown in Chart , Cp′TiCl 2 (O-2,6- i Pr 2 -4-RC 6 H 2 ) [R = H, Cp′ = Cp* ( 1 ), t BuC 5 H 4 ( 3 ); R = SiEt 3 , Cp′ = Cp* ( 2 )] and CpTiCl 2 (N = C t Bu 2 ) ( 4 ), have been chosen in this study − because these catalysts demonstrated efficient comonomer incorporations in the ethylene copolymerizations with sterically encumbered olefins, ,− cyclic olefins, − and aromatic vinyl monomers. , An AlMe 3 -free MAO white solid, which was prepared from the commercially available MAO sample [8.9 wt % (Al) toluene solution, see the Experimental Section] by removing toluene and AlMe 3 in vacuo , ,− ,− was used as the cocatalyst. The results by the ordinary linked-amide half-titanocene, [Me 2 Si­(C 5 Me 4 )­(N t Bu)]­TiCl 2 ( 5 ), , and the metallocene catalyst, Cp 2 ZrCl 2 ( 6 ), conducted under the same conditions are also placed for comparison.…”

“…The linked half-titanocene ( 5 ) showed rather low catalytic activity than the phenoxide-modified catalysts ( 1 , 2 ), and the resultant polymer possessed a rather high T m value (108 °C, run 8) compared to those prepared using 1 and 2 ( T m = 59.5–60.5 °C, runs 2–5), suggesting that 5 showed less My incorporation than 1 and 2 . It was also revealed that MAO itself gave a low molecular weight polymer ( M n = 2200, run 1), probably via a cationic manner in small amounts, , but attempts for separation by extracting the homopolymer with acetone through centrifugation , generally gave a tiny trace (negligible) amount of polymer collected as an acetone soluble fraction. Due to low polymer yield (run 8), it seemed difficult to separate poly­(My) formed by MAO itself, as described below.…”

“…AlMe 3 -Free MAO white solids (d-MAO) were prepared by removing toluene and AlMe 3 from the commercially available methylaluminoxane (MAO) [TMAO-S, 9.5 wt % (Al) toluene solution, Tosoh Finechem Co.] in vacuo in the dry box (at ca. 50 °C for removing toluene and AlMe 3 , and then heated at >100 °C for 1 h for completion). ,− ,− Cp*TiCl 2 (O-2,6- i Pr 2 C 6 H 3 ) ( 1 ), Cp*TiCl 2 (O-2,6- i Pr 2 -4-SiEt 3 -C 6 H 2 ) ( 2 ), t BuC 5 H 4 TiCl 2 (O-2,6- i Pr 2 C 6 H 3 ) ( 3 ), CpTiCl 2 (N = C t Bu 2 ) ( 4 ), and [Me 2 Si­(C 5 Me 4 )­(N t Bu)]­TiCl 2 ( 5 ) , were prepared according to the reported procedure. Cp 2 ZrCl 2 ( 6 ) (Kanto Kagaku Co. Ltd.) was used as received.…”

“…We herein present that the synthesis of the random E/My copolymers has been attained by the phenoxide-modified halftitanocene catalysts, Cp*TiCl 2 (O-2,6-i Pr 2 -4-RC 6 H 2 ) [R = H (1), 36 SiEt 3 (2) 37 ], which has been known as efficient catalysts 38−40 for ethylene copolymerization with aromatic vinyl monomers 41,42 as well as sterically encumbered olefins, 43−47 containing a cyclopentane unit, presumably formed by cyclization after 2,1-or 1,4-My incorporation (through π-allyl intermediates assumed as dormant) and subsequent ethylene insertion (Scheme 1). Moreover, interestingly, the resultant poly(E-co-My)s display unique tensile and elastic behavior depending on the My content (also see movies in the Supporting Information, SI).…”

“…We herein present that the synthesis of the random E/My copolymers has been attained by the phenoxide-modified half-titanocene catalysts, Cp*TiCl 2 (O-2,6- i Pr 2 -4-RC 6 H 2 ) [R = H ( 1 ), SiEt 3 ( 2 )], which has been known as efficient catalysts − for ethylene copolymerization with aromatic vinyl monomers , as well as sterically encumbered olefins, − in the presence of the methylaluminoxane (MAO) cocatalyst. It has also been demonstrated that the resultant poly­(E- co -My)­s possessed a unique microstructure containing a cyclopentane unit, presumably formed by cyclization after 2,1- or 1,4-My incorporation (through π-allyl intermediates assumed as dormant) and subsequent ethylene insertion (Scheme ).…”