Exploitation of rare earth catalysts in polymer syntheses

Shen, Zhiquan

doi:10.1007/s11458-006-0031-z

Cited by 9 publications

(6 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In fact, the double OH end groups in this kind of PCL allow the further functionalization of the PCL in the preparation of triblock copolymers 4. Rare‐earth complexes in ring‐opening polymerizations are an active research area for their high activity, lower toxicity, and good control over the molecular weight distribution 5. Therefore, lanthanide borohydrides as efficient initiators in the preparation of hydroxytelechelic PCLs have received great attention for their novel initiation mechanism 2…”

Section: Introductionmentioning

confidence: 99%

“…4 Rare-earth complexes in ring-opening polymerizations are an active research area for their high activity, lower toxicity, and good control over the molecular weight distribution. 5 Therefore, lanthanide borohydrides as efficient initiators in the preparation of hydroxytelechelic PCLs have received great attention for their novel initiation mechanism. 2 Tetrahydrosalen-supported metal complexes, for their specific coordination properties, have been explored extensively in recent times.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Tetrahydrosalen‐stabilized, chloride‐containing rare‐earth complexes: Facile initiator precursors for the preparation of hydroxytelechelic poly(ε‐caprolactone)s

Sun

Shen

2009

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

End-capped poly(e-caprolactone)s (PCLs) have been prepared elsewhere by various initiators. However, hydroxytelechelic PCLs have been reported less frequently, although there are two hydroxyl end groups in one polymer chain, which allows diversified functionalization. Two tetrahydrosalen-backboned chlorides containing rare-earth complexes, YbLCl(DME) 2 and ErLCl(DME) {where L is 6,60 -[ethane-1,2-diylbis(methylazanediyl)]bis (methylene)bis(2,4-di-tert-butylphenol) and DME is dimethoxyethane}, were first synthesized in this study, and they were used as initiator precursors for a ring-opening polymerization in the presence of NaBH 4 to afford hydroxytelechelic PCLs. The polymerization under different conditions was investigated, and a possible mechanism is proposed.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tetrahydrosalen‐stabilized, chloride‐containing rare‐earth complexes: Facile initiator precursors for the preparation of hydroxytelechelic poly(ε‐caprolactone)s

Sun

Shen

2009

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

show abstract

“…Lanthanide derivatives form an emerging and promising class of polymerization initiators/catalysts. For instance, they had been found to have high activity for the polymerization of olefins, isocyanates, and cyclic esters . Rabe et al reported the polymerization of the DEVP mediated by rare‐earth tris(amide) compounds.…”

Section: Introductionmentioning

confidence: 99%

Syntheses and properties of poly(diethyl vinylphosphonate) initiated by lanthanide tris(borohydride) complexes: Polymerization controllability and mechanism

Ling

et al. 2013

J. Polym. Sci. Part A: Polym. Chem.

Self Cite

View full text Add to dashboard Cite

Polymerization of diethyl vinylphosphonate (DEVP) is achieved by using lanthanide tris(borohydride) complexes, Ln(BH4)3(THF)3 (Ln = Y, La, Nd, Sm, Gd, Dy, Lu) as an initiator. The characteristics and mechanism of polymerization as well as the properties of the resulting poly(diethyl vinylphophonate)s (PDEVPs) are studied. The effects of the lanthanide elements, the molar ratios of monomer to initiator ([M]/[ln]), reaction temperature and time on polymerization have been investigated in detail. The optimized polymerization conditions are 40 °C, 1 h in bulk with [M]/[ln] = 300. The kinetic study indicates that the polymerization of DEVP undergoes a controlled manner as the molecular weights (MWs) of PDEVPs increase with monomer conversion linearly maintaining moderate MW distribution (1.7–1.9). Additionally, a coordination anionic polymerization mechanism is proved by end‐group analysis with ESI mass and 1H NMR spectroscopy. The obtained PDEVPs have low glass transition temperature (Tg = −62 °C) and high thermal decomposition temperature (Td > 300 °C) determined by differential scanning calorimetry and thermogravimetric analysis respectively. The thermosensitive behavior of PDEVP is characterized by evaluating the lower critical solution temperature of PDEVP in water by ultraviolet transmittance. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2409–2415

show abstract

“…Our group has made much effort to exploit rare earth catalysts in polymer syntheses [30] . Recently, it was found that the rare earth Schiff base complexes can be used as single component catalysts for the ring-opening polymerization of ε-caprolactone [31][32][33] , Nd(H 2 Salen) 2 Cl 3 .…”

Section: Introductionmentioning

confidence: 99%

Room temperature polymerization of alkyl isocyanates catalyzed by rare earth Schiff base complexes

Yang

Shen

2009

Sci. China Ser. B-Chem.

Self Cite

View full text Add to dashboard Cite

The polymerization of alkyl isocyanates catalyzed by rare earth chloride salen complexes/triisobutyl aluminum (Ln(H 2 salen) 2 Cl 3 ·2C 2 H 7 OH/Al(i-Bu) 3 ) at room temperature was investigated. The influences of ligand structure, catalyst composition, polymerization temperature, polymerization time, the concentration of catalyst and monomer, and the polymerization solvent on the polymerization of isocyanates were studied. It was found that under the polymerization conditions, examined La(H 2 salen A ) 2 Cl 3 ·2C 2 -H 7 OH/Al(i-Bu) 3 (H 2 salen A = N,N'-disalicylideneethylene diamine) is a fairly high efficient catalyst for the polymerization of n-hexyl isocyanate (n-HexNCO) to prepare high molecular weight poly(n-hexyl isocyanate) (PHNCO) with narrower molecular weight distribution at room temperature. PHNCO could be prepared with yield of 74.0%, number-average molecular weight (M n ) of 40.20×10 4 and MWD of 1.79 under the following optimum conditions: [Al]/[La] = 30 (molar ratio), [n-HexNCO]/[La] = 100 (molar ratio), [n-HexNCO] = 3.43 mol/L polymerization at 20℃ for 12 h in toluene.In the same polymerization conditions, poly (n-octyl isocyanate) (PONCO) with yield of 67.3%, and poly(n-butyl isocyanate) (PBNCO) with yield of 45.5%, could be prepared respectively. The kinetics of the polymerization of n-HexNCO was also investigated and found to be first-order with respect to both monomer and catalyst concentrations.rare earth catalyst, Schiff base complex, polymerization, alkyl isocyanate

show abstract

Exploitation of rare earth catalysts in polymer syntheses

Abstract: The studies over forty years on rare earth catalysts in polymer syntheses of diene, alkyne, alkylene oxide, thiirane, carbon dioxide copolymerization, lactide, caprolactone, cyclic carbonate and so forth in China have been reviewed.

Cited by 9 publications

References 78 publications

Tetrahydrosalen‐stabilized, chloride‐containing rare‐earth complexes: Facile initiator precursors for the preparation of hydroxytelechelic poly(ε‐caprolactone)s

Tetrahydrosalen‐stabilized, chloride‐containing rare‐earth complexes: Facile initiator precursors for the preparation of hydroxytelechelic poly(ε‐caprolactone)s

Syntheses and properties of poly(diethyl vinylphosphonate) initiated by lanthanide tris(borohydride) complexes: Polymerization controllability and mechanism

Room temperature polymerization of alkyl isocyanates catalyzed by rare earth Schiff base complexes

Contact Info

Product

Resources

About