Controlled Ring-Opening Polymerization of ε-Caprolactone Promoted by “in Situ” Formed Yttrium Alkoxides

Martin, Éric; Dubois, Philippe; Jérôme, Robert

doi:10.1021/ma991045r

Cited by 142 publications

(95 citation statements)

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“…More recently, the polymerization of "-CL initiated by [tris(hexamethyldisilyl)amide]yttrium in the presence of an excess of 2-propanol (< 100 mequiv.) has been reported by Jérôme and co-workers [15]. Quantitative monomer conversion is observed at ambient temperature and values for M n 6 22 000 (PDI 6 1:2/ are obtained.…”

Section: Lanthanide-initiated Ring-opening Polymerization (Rop) Of Cysupporting

confidence: 65%

Transition metal-based polymer chemistry: a critical micro-review

Buchmeiser¹

2002

Designed Monomers and Polymers

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Abstract-This micro-review summarizes mainly recent (i.e. mostly later than 1995) and important developments in transition metal-catalyzed polymerization and their impact on polymer synthesis. It is not intended to be entirely comprehensive, yet will focus on signi cant improvements or interesting aspects in certain areas of polymer chemistry. For this particular reason, not all transition metal-based polymerizations will be fully covered. Instead, besides providing a 'snapshot' of the state of the art, it was a major intention to outline the main advantages and disadvantages of certain important polymerizations in a critical, yet hopefully objective way.

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Section: Lanthanide-initiated Ring-opening Polymerization (Rop) Of Cysupporting

confidence: 65%

Transition metal-based polymer chemistry: a critical micro-review

Buchmeiser¹

2002

Designed Monomers and Polymers

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“…61 and other authors for various metal complexes. [62][63][64] The formation of an alkoxide species suggests that the mechanism of polymerization is via coordination-insertion and that an activated-monomer mechanism is less plausible. 65 However, in order to fully rule out the latter mechanism, further studies involving installation of less potent nucleophiles on the Al center would be required.…”

Section: Ring-opening Polymerization Of ε-Caprolactonementioning

confidence: 99%

Aluminum Methyl and Chloro Complexes Bearing Monoanionic Aminephenolate Ligands: Synthesis, Characterization, and Use in Polymerizations

et al. 2012

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Abstract:A series of aluminum methyl and chloride complexes bearing 2(N-piperazinyl-N′-methyl)-2-methylene-4-R′-6-R-phenolate or 2(N-morpholinyl)-2-methylene-4-R′-6-R-phenolate ([ONE R1,R2 ]-) {[ R 1 = t Bu, R 2 = Me, E = NMe (L1); R 1 = R 2 = t Bu, E = NMe (L2); R 1 = R 2 = t Bu, 1 E = O (L3)} ligands were synthesized and characterized through elemental analysis, 1 H, 13 The catalytic activity of complexes 1-3 toward ring-opening polymerization (ROP) of ε-caprolactone was assessed. These complexes are more active than analogous Zn complexes for this reaction but less active than the Zn analogs for ROP of rac-lactide. Characteristics of the polymer as well as polymerization kinetics and mechanism were studied. Polymer end-group analyses were achieved using 1 H NMR spectroscopy and MALDI-TOF MS. Eyring analyses were performed and the activation energies for the reactions were determined, which were significantly lower for 1 and 2 compared with 3. This could be for several reasons: (1) the methylamine (NMe) group of 1 and 2, which is a stronger base than the ether (O) group of 3, might activate the incoming monomer via non-covalent interactions, and/or (2) the ether group is able to temporarily coordinate to the metal center and blocks the vacant coordination site towards incoming monomer, whilst the amine cannot do this. Preliminary studies using 4 and 5 towards copolymerization of cyclohexene oxide with carbon dioxide have been performed. 4 was inactive and 5 afforded polyethercarbonate (66.7% epoxide conversion, polymer contains 54.0% carbonate linkages).

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“…The ring-opening polymerization of ε-CL was carried out in bulk in the presence of EVOH with and without Sn(Oct) 2 . The mass ratios of ε-CL and EVOH were kept constant for all systems.…”

Section: Polymerization Of ε-Cl Initiated By Hydroxyl Group On Evoh Imentioning

confidence: 99%

“…Figure 1 also shows that lower content of ethylene in EVOH (and thus higher content of hydroxyl group) causes a relatively faster overall polymerization rate. Figure 2 shows the increase of M n of the product along with monomer conversion for the systems without Sn(Oct) 2 . The increase of M n with conversion may be due to two reasons: the initiation of new chains by hydroxy group on the backbone of EVOH, and the propagation of the side chains.…”

Section: Polymerization Of ε-Cl Initiated By Hydroxyl Group On Evoh Imentioning

confidence: 99%

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Synthesis and Characterization of Poly(ethylene-co-vinyl alcohol)-graft-poly(ε-caprolactone)

Jiang

Liu

et al. 2002

Polym J

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ABSTRACT:Graft poly(ε-caprolactone)s (PCLs) with high graft density were synthesized by using random copolymer poly(ethylene-co-vinyl alcohol) (EVOH) to initiate ring-opening polymerization of ε-caprolactone, with and without cocatalyst Sn(Oct) 2 . The graft copolymer were characterized by IR, 1 H and 13 C NMR. The solution property and the crystallization behavior were also investigated.KEY WORDS Poly(ε-caprolactone) (PCL) / Poly(ethylene-co-vinyl alcohol) (EVOH) / Graft Copolymer / Poly(ε-caprolactone) (PCL) is a central important environmental friend and biocompatible polymer. It was synthesized through ring opening polymerization of ε-caprolactone (ε-CL) with various initiators or catalysts. 1, 2 Recently, macromolecular engineering of PCL 3 was also developed in order to synthesize block, graft and hyperbranched (co)polymers.Graft copolymerization of ε-CL can improve the mechanical properties of the homopolymers and the product can also be used as compatibilizer in polymer blends. There are generally two approaches to prepare graft copolymer of PCL. One of them is the macromonomer technique, in which PCL bearing a terminal double bond was synthesized beforehand. Using this approach, Jérôme and co-workers synthesized well-defined polystyrene-g-PCL, 4 poly(alkyl methacrylate)-g-PCL, 5 and poly(norborn-ene)-g-PCL 6 by controlled radical or organometallic catalyzed copolymerization of corresponding monomers and premade PCL macromonomers. The other approach is the "grafting form" technique in which the polymerization of ε-CL is (co)initiated by pendent hydroxyl group of a polymer backbone. For example, many natural polyhydroxy macromolecules such as starch, 7 dextran, 8 chitin, 9 and hydroxycellulose, 10 as well as synthetic polymers such as polyvinyl alcohol, 11 poly(ethylene-co-vinyl alcohol) (EVOH) 12 and functionalized polypropylene, 13 were grafted with PCL by ring opening polymerization from their pendent hydroxyl group. In addition, samarium-mediated graft polymerization of ε-CL on functionalized poly(pxylylene)s was also achieved. 14 In this paper, we report the synthesis and properties of a highly grafted copolymer, EVOH-g-PCL. The product is different from that in ref 12 in graft den- † To whom correspondence should be addressed. sity because the hydroxyl content of EVOH in ref 12 ranges from 3.1 to 6.7 mol% and we use EVOH with much larger hydroxyl contents in this work. Therefore the graft density is so high that the copolymer exhibits special solution and crystallization properties. We will discuss these in details in the following. And the graft copolymer can lead to different end applications, for instance, hand-mouldable and degradable package. EXPERIMENTAL Materialsε-Caprolactone (Aldrich, 99%) was distilled over calcium hydride under a reduced pressure before use. EVOHs (ethylene content 44 mol% and 27 mol%, Aldrich; ethylene content 32 mol%, Kuraray, Japan) were dried at 50 • C in vacuo for 24 h. Stannous 2-ethylhexanoate (Aldrich, 95%) was used as received. PolymerizationIn a typical experime...

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Controlled Ring-Opening Polymerization of ε-Caprolactone Promoted by “in Situ” Formed Yttrium Alkoxides

Cited by 142 publications

References 24 publications

Transition metal-based polymer chemistry: a critical micro-review

Transition metal-based polymer chemistry: a critical micro-review

Aluminum Methyl and Chloro Complexes Bearing Monoanionic Aminephenolate Ligands: Synthesis, Characterization, and Use in Polymerizations

Synthesis and Characterization of Poly(ethylene-co-vinyl alcohol)-graft-poly(ε-caprolactone)

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