Abstract:
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The use of carbohydrate derivatives for polymer synthesis has attracted much attention not
only because of the huge abundance and renewable character of these resources, but also
due to the degradable and biocompatible behavior that can be expected for such polymers.
The cyclic monomer dimethyl 2,4:3,5-di-O-methylene galactarate, which was synthesized
from galactaric acid, has several attractive features linked to its rigidity, chirality, non-toxicity
and hydrophilicity.
Aliphatic homopolyesters poly(alkylene 2,4:3,5-di-O-methylene galactarate)s were
prepared from dimethyl 2,4:3,5-di-O-methylene galactarate and the aliphatic α,ω-diols 1,6-
hexanediol; 1,8-octanediol; 1,10-decanediol and 1,12-dodecanediol; and were
characterized by NMR, FT-IR, viscosimetry and GPC. According to the asymmetric
constitution of the galactarate unit, these polyesters displayed optical activity in solution.
The thermal behavior, mechanical properties and biodegradability of these polyesters were
evaluated and compared with those displayed by their homologues dimethyl adipatederived
homopolyesters.
All poly(alkylene 2,4:3,5-di-O-methylene galactarate)s and poly(alkylene adipate)s from
synthesis were semicrystalline. Glass transition temperatures of poly(alkylene 2,4:3,5-di-Omethylene
galactarate)s were higher than those observed for poly(alkylene adipate)s. The
introduction of ring acetal groups improved the thermal stability and caused an increase in
the elastic modulus and the tensile strength of the polyesters, and produced a reduction in
the elongation at break at the same time.
Finally, the degradation study revealed that poly(alkylene 2,4:3,5-di-O-methylene
galactarate)s were biodegradable polyesters, and that they degraded faster than
poly(alkylene adipate)s. |