Ethene−Norbornene Copolymerization with Homogeneous Metallocene and Half-Sandwich Catalysts:  Kinetics and Relationships between Catalyst Structure and Polymer Structure. 4. Development of Molecular Weights

Abstract

The molecular weights of ethene-norbornene copolymers, produced with various metallocene- and amidocyclopentadienyl-methylaluminoxane (MAO) catalysts, have been determined by high-temperature gel-permeation chromatography: with one exception, increasing molecular weights were found with an increasing norbornene content in the copolymer. This observation is due to the fact that the beta-hydride elimination process is not possible in the case of norbornene, because of special steric conditions of the cis-2,3-exo inserted norbornene; other possible termination reactions are discussed, considering the specialties of the norbornene. The effect of the catalyst structure on the molecular weights is discussed in terms of steric and electronic factors of the different ligands: sterically less hindered ligands produce ethene-norbornene copolymers with relatively low molecular weights; ligands with a larger extension and electron-pushing effect such as the fluorenyl ligand, induced the formation of high molecular weights. Additional alkyl groups at the indenyl or fluorenyl ligand increased the molecular weights additionally.

Design of Efficient Molecular Catalysts for Synthesis of Cyclic Olefin Copolymers (COC) by Copolymerization of Ethylene and α-Olefins with Norbornene or Tetracyclododecene

“…Moreover, the T g values increased upon increasing the NBE content, as estimated by 13 C NMR spectra. The copolymerization of NBE with HX by ( t BuC 5 H 4 )TiCl 2 (N=C t Bu 2 ) (8)-MAO catalyst proceeded with moderate catalytic activity that is comparable to that of the reported Flu-CGC (4)-Ph 3 CB(C 6 F 5 ) 4 catalyst [62], and the activity increased upon increasing the NBE concentration charged.…”

“…The resultant copolymers possessed rather high molecular weights with unimodal molecular weight distributions (Mn = 12,000-27,600, Mw/Mn = 1.20-1.76), and the TCD content (estimated by 13 C NMR spectra) increased upon increasing TCD concentration with an increasing glass transition temperature (Tg); synthesis of the copolymers with high Tg (e.g., 286 °C) could be thus attained by adopting this catalysis. The activity was also affected by MAO (Al/Ti molar ratio), especially under high TCD concentration conditions, and no Plots of glass transition temperature (T g ) vs NBE content (mol %) in (a) poly(NBE-co-1-hexene)s by Cp'TiCl 2 (N=C t Bu 2 ) (Cp' = Cp (7, ) or t BuC 5 H 4 (8, ))-MAO catalysts; (b) poly(NBE-co-1-hexene)s (marked with ) and poly(NBE-co-1-octene)s (marked with ); (c) plots of T g values vs TCD content (mol %) in poly(TCD-co-1-hexene)s and poly(TCD-co-1-dodecene)s; (d) plots of transmittance vs wavelength in poly(TCD-co-1-hexene) [54].…”

“…Many have reported on ethylene copolymerization with norbornene (NBE) using ordinary metallocenes [10][11][12][13][14][15][16][17], half-titanocenes [18][19][20][21][22][23][24][25][26], and others [27][28][29][30], however, successful examples of the efficient synthesis of random, high molecular weight copolymers with high Tg values (high NBE content) have been limited. Ethylene copolymers with tetracyclododecene (TCD, dimethanooctahydronaphthalene) are also known as promising materials [9], and are produced by using classical Ziegler-type vanadium catalyst systems (VOCl3, VO(OEt)Cl2-EtAlCl2•Et2AlCl, etc.)…”

Synthesis of High Performance Cyclic Olefin Polymers (COPs) with Ester Group via Ring-Opening Metathesis Polymerization

“…Based on performance characteristics, the applications of COCs and COPs have now been extended to production of optical parts for digital cameras and laser beam printers, medical products, and electrical insulation [1,4]. As shown in Scheme 1, COCs are obtained through copolymerization of cycloolefin with ethylene or α-olefin [5][6][7][8][9][10][11][12][13][14], and commercialized under the trade names APEL ® by Mitsui and TOPAS ® by TOPAS advanced polymers (TAP: formerly Ticona and Hoechst) [15,16]. COPs are prepared via ring-opening metathesis polymerization (ROMP) of cycloolefin followed by hydrogenation [17][18][19][20][21][22][23][24], and commercialized under the trade names Zeonex ® and Zeonor ® by Zeon [25] and Arton ® by Japan Synthetic Rubber (JSR) [20,21].…”

Phosphine-Thiophenolate Half-Titanocene Chlorides: Synthesis, Structure, and Their Application in Ethylene (Co-)Polymerization

“…[44][45][46][47][48][49][50][51][52][53][54][55][56] Figure 3A showed that the microstructures of the COCs formed using 2a under low NBE concentration of 0.3 mol/L possessed alternating ethylene-NBE sequences and isolated NBE units. In contrast, resonances ascribed to NBE diads or triads were observed for the copolymers prepared at high NBE concentration of 0.5-1.0 mol/L (Figures 3B-C), and the microstructures thus possessed a mixture of NBE repeat units in addition to the alternating, isolated NBE sequences.…”