Biologisch abbaubare Polymere. 2. Mitt.: Zur Homo‐ und Copolymerisation von D,L‐Dilactid

Rafler, G.; Dahlmann, J.

doi:10.1002/actp.1990.010411205

Cited by 23 publications

(9 citation statements)

References 18 publications

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“…Hence, by performing corresponding investigations one has to bear in mind that the polymer originating from the reaction is no stable product but can undergo relatively fast changes, especially under the influence of this compounds [2]. It was expected that the employment of tin compounds as accelerators in ring-opening polymerization leads not only to gradual effects but involves also very different reaction mechanisms.…”

Section: Et3sn(-o-ch-co-o-ch-co-nmejnmentioning

confidence: 99%

“…They are mostly prepared by ring-opening polymerization of their corresponding cyclic esters in presence of tin(I1) dioctonoate.Various othertin compounds are suited as well, but it is reported that by using tetraphenyl tin, for instance, the reproducibility is not satisfactory [ l].There is no satisfactory evidence concerning the mechanism of the Sn-initiated or catalyzed polymerization [2]. are biodegradable and simultaneously distinguished by their good biocompatibility.…”

Section: Introductionmentioning

confidence: 99%

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Biodegradable polymers. 7th comm. On the mechanism of ring‐opening polymerization of cyclic esters of aliphatic hydroxycarboxylic acids by means of different tin compounds

Dahlmann

Rafler

1993

Acta Polymerica

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To elucidate the effect of tin compounds in the ring-opening polymerization of lactides and lactones, D,L-dilactide was taken as an example, and its reaction with different tin compounds at a molar ratio of 1: 1 as well as the polymer formation and degradation in dependence of its concentration has been investigated. Two entirely different reaction courses were observed which are consequently influenced by compounds with alcoholic and/or carboxylic OH groups in different ways. Biologisch abbaubare Polymere. 7. Mitt.: Z u m Mechanismus der Ringoffnungspolymerisation cyclischer Ester von aliphatischen Hydroxy-carbonsauren mit verschiedenen ZinnverbindungenUm den Einflulj von Zinnverbindungen bei der Ringoffnungspolymerisation von Lactiden und Lactonen aufzuklaren, wurde D,L-Dilactid als Beispiel eingesetzt. Die Reaktion mit verschiedenen Zinnverbindungen beim Molverhaltnis 1: 1 sowie die Polymerbildung und der Polymerabbau in Abhangigkeit von der Konzentration wurden untersucht. Es wurden zwei verschiedene Reaktionswege gefunden, die durch Verbindungen mit alkoholischen und/oder carboxylischen OH-Gruppen unterschiedlich beeinfluljt werden.

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Section: Et3sn(-o-ch-co-o-ch-co-nmejnmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Biodegradable polymers. 7th comm. On the mechanism of ring‐opening polymerization of cyclic esters of aliphatic hydroxycarboxylic acids by means of different tin compounds

Dahlmann

Rafler

1993

Acta Polymerica

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“…Poly(ϵ‐caprolactone) (PCL) and poly( L ‐lactide) (PLLA) have been under extensive study since they were introduced as potential biodegradable polymers. Most of the polymerization studies have dealt with the synthesis of linear1–5 and branched6–11 polymers. Crosslinking of these polymers has received less attention, but is of great interest because it would expand the possible applications 12–16.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, characterization and crosslinking of functional star‐shaped poly(ε‐caprolactone)

Turunen

Korhonen

Tuominen

et al. 2001

Polymer International

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Star‐shaped low molecular weight poly(ε‐caprolactone)s (PCLs) were synthesized and functionalized with crosslinkable terminal groups for subsequent crosslinking. The ε‐caprolactone (CL) prepolymers were polymerized by ring‐opening in the presence of polyglycerine (PGL) as an initiator (1, 3 and 5 mol%) and Sn(II)2‐ethylhexanoate as a catalyst. Characterization of the prepolymer by 13C/1H nuclear magnetic resonance (NMR) spectroscopy, size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) revealed a six‐armed star‐shaped structure for the prepolymer with the molecular weight controlled by the ratio of PGL and CL. Functionalization of the hydroxyl‐terminated prepolymer was carried out with maleic or itaconic anhydride. In both cases, the characterization of the functionalized prepolymer showed that the hydroxyl groups were completely substituted. The functionalized PCLs were successfully crosslinked through the reaction of double bonds. The crosslinking was induced either thermally with organic peroxide or photochemically with a photosensitive initiator. Characterization of the crosslinked PCLs by Soxhlet extraction, DSC and FTIR showed that the itaconic double bond was much more reactive in thermal crosslinking than the maleic double bond. Thus, the crosslinked prepolymers that were functionalized with itaconic double bonds achieved a gel content of about 90%. A gel content of 100% was achieved with several compositions where crosslinking agents were employed. © 2002 Society of Chemical Industry

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“…This line of products is the subject of a number of research programmes in the world, and it seems that plans for the industrial manufacture of polylactides will be realized in the near future [ 4 2 4 ] . The fermentative production of lactic acid 1 can be cost-effective without subsidies for raw materials [6, 451; the ring opening of dilactide 4 is a high-yield process (up to 90 per cent) [46][47][48]. The high costs of target polymer 5 are due to the production of dilactide 4.…”

Section: Introductionmentioning

confidence: 99%

Formation of aminium lactates in lactic acid fermentation preparation and characterization of 1,4‐piperazinium‐(L,L)‐dilactate obtained fromL(+)‐lactic acid (part I)

Kamm¹,

Kamm²,

Richter³

1997

Acta Biotechnologica

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The potential for the production of 1.4-piperazinium-(L, L)-dilactate from L(+)-lactic acid preparations obtained by fermentation was studied. Piperazinium dilactate was found to be a very suitable source material for poly(1actic acid) production. In a novel polymerization process, the intermediate dilactide was directly formed in the salt melt at a moderate temperature. High-performance cultivation of Lucrobocillus pumcawi on a glucose-MRS medium was carried out using high-viability inocula. After the cell mass had been removed from the fermentation broth by centrifugation and/or ultrafiltration, the lactic acid solution was concentrated to 45% [wlw] by ; 1 two-stage electrodialysis process. Two methods of preparing 1,4-piperazinium dilactate were developed: the first from the medium-concentrated lactic acid ( 4 5 4 ) and the second from a highly-concentrated lactic acid (85%) obtained by evaporation from the first one. Because there were no physical data on 1,4-piperazinium-(l, L)-dilactate in specialized literature, the pure product was characterized according to its solubility characteristics. melting point and spectroscopic analysis.

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Biologisch abbaubare Polymere. 2. Mitt.: Zur Homo‐ und Copolymerisation von D,L‐Dilactid

Cited by 23 publications

References 18 publications

Biodegradable polymers. 7th comm. On the mechanism of ring‐opening polymerization of cyclic esters of aliphatic hydroxycarboxylic acids by means of different tin compounds

Biodegradable polymers. 7th comm. On the mechanism of ring‐opening polymerization of cyclic esters of aliphatic hydroxycarboxylic acids by means of different tin compounds

Synthesis, characterization and crosslinking of functional star‐shaped poly(ε‐caprolactone)

Formation of aminium lactates in lactic acid fermentation preparation and characterization of 1,4‐piperazinium‐(L,L)‐dilactate obtained fromL(+)‐lactic acid (part I)

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