Abstract
Novel biodegradable poly(ester-amide)s were prepared by ring-opening copolymerization of -caprolactone and 3- and/or 6-alkyl-substituted morpholine-2,5-dione derivatives. The copolymerizations were carried out in the bulk using stannous octoate as an initiator. Molecular weights of the copolymers ranged from 1,0 · 104 to 8,3 · 104 and decreased with increasing mole fractions of morpholine-2,5-dione derivatives in the feed. 13C NMR sequence analysis indicated that the copolymers had a random distribution of -oxycaproyl and depsipeptide units, which resulted from the occurrence of transesterification reactions during copolymerization. The results of the DSC measurements and 13C NMR sequence analysis showed a close relationship between the crystallinity and average length of ε-oxycaproyl blocks. Copolymers with a mole fraction of depsipeptide units smaller than 0,20 were semi-crystalline, whereas incorporation of larger amounts of depsipeptide units resulted in amorphous copolymers. The melting point depression as a function of the molar composition of the semi-crystalline copolymers was in good agreement with the melting point depression predicted by the Baur equation, which indicated the rejection of depsipeptide units from crystals consisting of ε-oxycaproyl units.
Original language | English |
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Pages (from-to) | 1927-1942 |
Number of pages | 16 |
Journal | Makromolekulare Chemie |
Volume | 193 |
Issue number | 8 |
DOIs | |
Publication status | Published - 1992 |
Keywords
- METIS-105253
- IR-70994