TY - JOUR A1 - Kricheldorf, H.R. A1 - Weidner, Steffen T1 - High Tg copolyesters of lactide, isosorbide and isophthalic acid T2 - European polymer journal N2 - 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 processing from the melt seems to be feasible up to temperatures of 260 °C without risking degradation. PB - Elsevier CY - Oxford KW - Lactide KW - Isosorbide KW - Ring-opening polymerization KW - Polycondensation KW - Cyclization PY - 2013 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/29014 AN - OPUS4-29014 SN - 0014-3057 SN - 1873-1945 VL - 49 IS - 8 SP - 2293 EP - 2302 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany