Controlled Ring-Opening Polymerization of Lactones and Lactides Initiated by Lanthanum Isopropoxide, 1. General Aspects and Kinetics

Save, Maud; Schappacher, Michel; Soum, Alain

doi:10.1002/1521-3935(20020401)203:5/6<889::aid-macp889>3.0.co;2-o

Cited by 569 publications

(531 citation statements)

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“…Based on previous work with alkylsubstituted δ-valerolactones, we suspected the ceiling temperature for the polymerization of βMδVL might be low (28,37,38). To favor high conversion we therefore conducted the polymerizations in bulk monomer at room temperature using the highly active organocatalyst triazabicyclodecene (TBD) (Fig.…”

Section: Construction Of a Nonnatural Metabolic Pathway For Biosynthementioning

confidence: 99%

Scalable production of mechanically tunable block polymers from sugar

Xiong¹,

Schneiderman

Bates³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

174

205

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Significance In recent years there has been extensive research toward the development of sustainable polymeric materials. However, environmentally benign, bioderived polymers still represent a woefully small fraction of plastics and elastomers on the market today. To displace the widely useful oil-based polymers that currently dominate the industry, a bioderived synthetic polymer must be both cost and performance competitive. In this paper we address this challenge by combining the efficient bioproduction of β-methyl-δ-valerolactone with controlled polymerization techniques to produce economically viable block polymer materials with mechanical properties akin to commercially available thermoplastics and elastomers.

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Section: Construction Of a Nonnatural Metabolic Pathway For Biosynthementioning

confidence: 99%

Scalable production of mechanically tunable block polymers from sugar

Xiong¹,

Schneiderman

Bates³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

174

205

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“…This suggests that the smaller metal, Y, does not dimerize as readily as Gd, as it is sufficiently shielded by the bulky ligand and perhaps, only exists in its monomeric form in solution so initiates polymerization more rapidly. Interestingly, 25 Given the variety of coordination-insertion mechanisms that are possible using these initiators, it may be that the Y species facilitates the ROP by a different mechanism to its Gd analogue.…”

Section: Reactivity Of Ln-cl Complexes Towards E-caprolactonementioning

confidence: 99%

Lanthanide chloride complexes of amine-bis(phenolate) ligands and their reactivity in the ring-opening polymerization of ε-caprolactone

et al. 2008

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Reaction of two equivalents of n-BuLi with sterically demanding amine-bis(phenol) compounds, H 2 O 2 NN R (Me 2 NCH 2 CH 2 N{CH 2 -3,5-R 2 -C 6 H 2 OH} 2 ; R = t-Bu or t-Pe (tert-pentyl)) yields isolable lithium complexes, Li 2 (O 2 NN R ), in good yields. Upon reaction with one equivalent of LnCl 3 (THF) x , the lithium salts afford rare earth amine-phenolate chloride complexes in good yields, Ln(O 2 NN R )Cl(THF); Ln = Y, Yb, Ho, Gd, Sm, Pr. Crystals of Y(O 2 NN t-Bu )Cl(THF), 1, and Sm(O 2 NN t-Bu )Cl(DME), 2, suitable for single crystal X-ray crystallographic analysis were obtained. In contrast to previously reported [{Gd(O 2 NN t-Pe )(THF)(l-Cl)} 2 ] and related La and Sm complexes, these species are monomeric. 1 contains Y in a distorted octahedral environment bonded to two amine, two phenolate, one THF and one chloride donor. 2 contains Sm in a distorted capped trigonal prismatic environment bonded to two amine, two phenolate, two DME oxygens and one chloride donor. The Ln(O 2 NN t-Pe )Cl(THF) complexes were active initators for the controlled ring-opening polymerization of e-caprolactone with a tendency to form low molecular weight cyclic polyesters (M n 3000-5000). The conversion rates, although slower than related amido and alkyl species, were different for monomeric and dimeric initiators. The size of the metal centre also affected the conversions and the molecular weights achieved.

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“…Hiltunen et al [20] measured molar masses 2-3 times smaller by titration than by SEC. Kowalsky et al [21] and Save et al [23] reported the same feature and found that the error depends on the chemical structure of the polymer and its mass range. They proposed a correction factor ranging from 0.54 to 0.58 depending on the polymer.…”

Section: Comparison Of Molar Mass Data Obtained By 1 H-nmr and Secmentioning

confidence: 72%

“…The above comment illustrates one of the reasons why the determination of molar mass by SEC with a refractive index or light scattering detector for polyesters is controversial in chloroform. Several authors have recently highlighted that polystyrene-calibrated SEC measurements in chloroform overestimate the real M n -by at least 50% in the range above 10 4 g·mol -1 for poly("-caprolactone), polylactide and related copolyesters [18][19][20][21][22][23][24]. For these reasons, researchers have used complementary techniques such as MALDI-TOF mass spectrometry [19,25].…”

Section: Introductionmentioning

confidence: 99%

Solution viscosity – molar mass relationships for poly(butylene succinate) and discussion on molar mass analysis

Charlier¹,

Girard²,

Freyermouth³

et al. 2015

Express Polym. Lett.

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Abstract. Poly(butylene succinate) (PBS) is currently developing due to its biodegradability and the similarity of its mechanical properties to those of polyolefins. Relationships between the number average molar mass, M n -, and solution viscosity such as [!] and ! red were derived for this aliphatic polyester. M n -values were determined by end-group analysis and size exclusion chromatography (SEC). Mark-Houwink-Sakurada (MHS) parameters were proposed in two solvents and for the different molar masses and viscosity measurement methods. As an example, the MHS equations were respectively, [!] = 6.4·10 -4 ·M n 0.67 in chloroform and [!] = 7.1·10 -4 ·M n -0.69 in 50/50 wt% 1,2-dichlorobenzene/phenol at 25°C for molar masses measured by SEC in hexafluoro isopropanol (HFIP) with poly(methyl methacrylate) (PMMA) standards. Empirical relationships were also suggested to derive M n -directly from reduced viscosity, ! red , which is much easier to determine than intrinsic viscosity. With these data, the number average molar mass of PBS can be conveniently estimated from a single viscosity measurement. In addition, it was shown that PBS contains 1-2 wt% of cyclic oligomers produced during esterification and that molar masses determined by taking this fraction into account or not were significantly different, especially for long chains.

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Controlled Ring-Opening Polymerization of Lactones and Lactides Initiated by Lanthanum Isopropoxide, 1. General Aspects and Kinetics

Cited by 569 publications

References 0 publications

Scalable production of mechanically tunable block polymers from sugar

Scalable production of mechanically tunable block polymers from sugar

Lanthanide chloride complexes of amine-bis(phenolate) ligands and their reactivity in the ring-opening polymerization of ε-caprolactone

Solution viscosity – molar mass relationships for poly(butylene succinate) and discussion on molar mass analysis

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