Synthesis and Characterization of Lactic Acid Based Telechelic Prepolymers

Autor:	Mika Härkönen, Kari Hiltunen, Jukka Seppälä, T. Väänänen
Rok vydání:	1996
Předmět:	Condensation polymer Telechelic polymer Adipic acid Lactide Polymers and Plastics Organic Chemistry Lactic acid Inorganic Chemistry End-group chemistry.chemical_compound Monomer chemistry Polymer chemistry Materials Chemistry Prepolymer
Zdroj:	Macromolecules. 29:8677-8682
ISSN:	1520-5835 0024-9297
DOI:	10.1021/ma960402k
Popis:	The synthesis of low molecular weight (Mn (NMR) < 7000 g/mol) lactic acid prepolymers by condensation polymerization of l-lactic acid was investigated. Besides the l-lactic acid polymer, hydroxyl- and carboxyl-terminated telechelic prepolymers were also prepared by the addition of small amounts of 1,4-butanediol and adipic acid, respectively. All polymerizations were carried out in a melt with tin octoate as the catalyst. The products were characterized by differential scanning calorimetry, gel permeation chromatography (GPC), IR, 1H-NMR, and 13C-NMR. According to NMR, the resulting prepolymers contained less than 1 mol % of lactic acid monomer and less than 4.1 mol % of lactide. End group analysis of the polymers was carried out by comparing the NMR spectra of different polymers. According to NMR, the lactic acid can be copolymerized so that the resulting prepolymer chains have only one kind of end group, hydroxyl or carbonyl. The integrated area of the identified end group peak (hydroxyl or acid) was th...
Databáze:	OpenAIRE
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