• Treffer 19 von 190
Zurück zur Trefferliste

High Tg copolyesters of lactide, isosorbide and isophthalic acid

  • Using SnCl2, ZnCl2, Zn-lactate or Zr-acetylacetonate as catalysts ʟ-lactide was oligomerized in bulk with isosorbide as initiator. The ratio isosorbide/lactide was varied from 8/2 to 2/8. The resulting oligomers were in situ polycondensed with isophthaloyl chloride in various aromatic solvents. In chlorobenzene homogeneous reaction mixtures were obtained, whereas molten copolyesters precipitated from toluene and xylene. The obtained average molecular weights indicated high polydispersities. According to MALDI-TOF MS the low molar mass reaction products (<4 kDa) almost exclusively consisted of cyclics with a composition depending on the feed ratio. The glass-transition temperatures (Tg) varied between the values of poly(ʟ-lactide (64 °C) and poly(isosorbide isophthalate) (180 °C). Four polyesters prepared from 5-tert-butyl isophthalic acid displayed higher Tg values. Differential thermoanalysis evidenced that the thermostability decreases with higher fractions of lactide, but processingUsing SnCl2, ZnCl2, Zn-lactate or Zr-acetylacetonate as catalysts ʟ-lactide was oligomerized in bulk with isosorbide as initiator. The ratio isosorbide/lactide was varied from 8/2 to 2/8. The resulting oligomers were in situ polycondensed with isophthaloyl chloride in various aromatic solvents. In chlorobenzene homogeneous reaction mixtures were obtained, whereas molten copolyesters precipitated from toluene and xylene. The obtained average molecular weights indicated high polydispersities. According to MALDI-TOF MS the low molar mass reaction products (<4 kDa) almost exclusively consisted of cyclics with a composition depending on the feed ratio. The glass-transition temperatures (Tg) varied between the values of poly(ʟ-lactide (64 °C) and poly(isosorbide isophthalate) (180 °C). Four polyesters prepared from 5-tert-butyl isophthalic acid displayed higher Tg values. Differential thermoanalysis evidenced that the thermostability decreases with higher fractions of lactide, but processing from the melt seems to be feasible up to temperatures of 260 °C without risking degradation.zeige mehrzeige weniger

Volltext Dateien herunterladen

  • 1-s2.0-S0014305713002310-main.pdf
    eng

Metadaten exportieren

Weitere Dienste

Teilen auf Twitter Suche bei Google Scholar
Metadaten
Autoren/innen:H.R. Kricheldorf, Steffen Weidner
Dokumenttyp:Zeitschriftenartikel
Veröffentlichungsform:Verlagsliteratur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):European polymer journal
Jahr der Erstveröffentlichung:2013
Organisationseinheit der BAM:1 Analytische Chemie; Referenzmaterialien
1 Analytische Chemie; Referenzmaterialien / 1.3 Strukturanalytik
Verlag:Elsevier
Verlagsort:Oxford
Jahrgang/Band:49
Ausgabe/Heft:8
Erste Seite:2293
Letzte Seite:2302
Freie Schlagwörter:Cyclization; Isosorbide; Lactide; Polycondensation; Ring-opening polymerization
DOI:https://doi.org/10.1016/j.eurpolymj.2013.05.007
ISSN:0014-3057
ISSN:1873-1945
Verfügbarkeit des Volltexts:Volltext-PDF im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:20.02.2016
Referierte Publikation:Ja
Datum der Eintragung als referierte Publikation:05.09.2013