Catholic polymerization of dl-lactide

Barskaya, I.G; Lyudvig, Ye.B.; Shifrina, R.R.; Izyumnikov, A.L.

doi:10.1016/0032-3950(83)90087-4

Cited by 11 publications

(11 citation statements)

References 5 publications

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“…1, Y is quite linear up to conversion values around 90% ( R 2 = 0.926 in the worst case). Such behavior has been previously reported 24, 37, 38. In our case, the loss of linearity is due to the limited accuracy of our experimental evaluation of the residual monomer amount by GPC for high conversions 39.…”

Section: Methodssupporting

confidence: 71%

Kinetics of the ring‐opening polymerization of D,L‐lactide using zinc (II) octoate as catalyst

Mazarro

Gracia

Rodrı́guez

et al. 2011

Polymer International

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The kinetics of ring-opening polymerization of D,L-lactide with 2-ethylhexanoic acid zinc (II) salt as catalyst and methanol as co-catalyst at different temperatures is investigated. A previously proposed kinetic model accounting for reactions such as activation, propagation, chain transfer, transesterification and thermal non-radical random chain scission has been applied to simulate the experimental results of conversion and average molecular weights. The relevance of some side reactions, mainly transesterifications and chain scission, has been verified all over the studied temperature range and the corresponding rate constants have been estimated.

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Section: Methodssupporting

confidence: 71%

Kinetics of the ring‐opening polymerization of D,L‐lactide using zinc (II) octoate as catalyst

Mazarro

Gracia

Rodrı́guez

et al. 2011

Polymer International

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“…Structural analysis revealed that this model complex has a dimeric structure with a single ligand conformation of L,L 50 in the solid state. 1 H NMR spectroscopy of this model complex revealed that the dimeric structure of the complex in the solid state is retained in solution, and the R configuration of the lactate ester has selectively induced the L conformation of the ligand in the complex because of steric repulsion, which additionally favors the insertion of (S,S)-LA.…”

Section: Formation Of Isotactic/stereoblock Plas From Rac-lamentioning

confidence: 99%

Single site catalysts for stereoselective ring-opening polymerization of lactides

2011

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Poly(lactide) (PLA) is the most well known biodegradable and biocompatible material among the aliphatic polyesters nowadays explored for biomedical, pharmaceutical and environmental applications. Different poly(lactide)s are distinguished, namely stereoregular PLLA and PDLA, atactic, heterotactic, syndiotactic and stereoblock PLAs. Because the stereochemistry of the monomeric units in the polymer chains plays a decisive role in the mechanical, physical and degradation properties of PLA materials, stereospecific catalysts to prepare different polylactide architectures are a major topic. In this review, after a general introduction on metal catalyzed ring opening polymerization, we mainly focus on single site catalyst systems inducing stereoselective polymerization of lactides.

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“…The zero order with respect to the monomer a t hydroxomechanism in the case of lactide (the linearity of the curves a t the main span -Figure I c ) may be related to the fact that in this system where in the presence of HC there preserves the association of ions into ion pairs -(TI-PI2) the limiting stage of the process is reaction (6).…”

Section: IImentioning

confidence: 99%

Cationic polymerization of lactones in the presence of hydroxyl‐containing compounds

et al. 1983

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The mechanism of cationic polymerization of lactones in the presence of hydroxyl-containing compounds (hydroxomechanism) has been studied taking as an example the polymerization of &propiolactone, 8-caprolactone, glycolide and lactide. In this mechanism chain propagation proceeds via preliminary chain transfer t o the monomer. This transfer accelerates the process, decreases the molecular weight of the polymer, narrows the molecular-mass distribution and enhances the general stability of the system. Die kationische Polymerisation von Laetonen in Gegenwart von hydroxylhaltigenVerbindungen Der Mechanismus der kationischen Polymerisation von Lactonen in Gegenwart hydroxylhaltiger Verbindungen (Hydroxomechanismus) wurde am Beispiel der Polymerisation von 8-Propiolacton, e-Caprolacton, Glycolid und Lactid untersucht. Bei diesem Mechanismus erfolgt das Kettenwachstum iiber eine vorhergehende Kettenubertragung auf das Monomer. Diese ffbertragungsreaktion beschleunigt den Prozell, verringert die rel. Molekulmasse des Polymers, verschmalert die Molekulmassenverteilung und erhoht die allgemeine Stabilitat des Systems. Icamuonnas nonuncepuaayua naxmnoe e npucymemeuu z u a p o m w o a e p w a q u x coeaunenuii Ha IIpFlMepe UOJIFlMepFla~FlH ~-llpOllFlOJIaKTOHa, &-KallpOJIaKTOHa, rJIHKOJIklAa Fl JIaKTHAa PaCCMOTpeH MeXaHL13M KaTllOHHOa llOJIHMepH3a~FlFl JlaKTOHOB B IlPHCYTCTBHH rFl~pOKCFlJICO~ep?Ka~HX COenFlHeHMa -, ,~HAPOKCOMeXaHH3M". B TOM ~e x a~~l a~e POCT qenn ~~O F~C X O A F~T nyTena npensapmenbHo€i nepefiaqa qenti H a MoHoMep. nepexon Ha Hero ysennwsaeT CKOPOCTH npoqecca, yMemruaeT MoneKympHsxe Macm nonmepa, cymaeT MoseKynspHo-Maccosoe paCllpe~eJIeHFle Fl YBenFlqFlBaeT 06rqym CTa6FlJIbHOCTb CFlCTeMbI. in the presence of hydroxyl-containing compounds K%z: process without HC Acta Polymeriu 34 (1983) Heft 11/12

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Catholic polymerization of dl-lactide

Cited by 11 publications

References 5 publications

Kinetics of the ring‐opening polymerization of D,L‐lactide using zinc (II) octoate as catalyst

Kinetics of the ring‐opening polymerization of D,L‐lactide using zinc (II) octoate as catalyst

Single site catalysts for stereoselective ring-opening polymerization of lactides

Cationic polymerization of lactones in the presence of hydroxyl‐containing compounds

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