Abstract
A series of copolymers of glycolic acid (GA), d,l-lactic
acid (dl-LA) and d,l-2-hydroxybutyric acid (dl-2HBA) were
prepared via melt condensation polymerization. The
utilized monomers represent mixtures that are present and
potentially obtainable from kraft black liquor by
fractionation. Polymerizations were performed in 165 °C
at nitrogen atmosphere and reduced pressure using
stannous octoate as catalyst. Copolymerizations were
conducted with varying dl-2HBA content in order to
observe how the presence of the dl-2HBA monomer affects
the properties of the polymers. Prepared copolymers were
characterized with 1H NMR and 13C NMR, size exclusion
chromatography, differential scanning calorimetry and
thermogravimetric analysis. The obtained copolymers had
molecular weights between Mw = 3500-10,000 g/mol. dl-2HBA
had a lowering effect on the glass transition
temperatures and molecular weights of the copolymers.
However, significant lowering of molecular weight was
observed only when the amount of dl-2HBA in the feed
exceeded 60%. The results indicate that dl-2HBA can be
copolymerized with GA and dl-LA and therefore the
corresponding kraft black liquor fractions can be
utilized for polymerizations.
Original language | English |
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Pages (from-to) | 774-778 |
Journal | European Polymer Journal |
Volume | 48 |
Issue number | 4 |
DOIs | |
Publication status | Published - 2012 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Polycondensation
- polyester
- biodegradable polymer
- biobased polymer