Synthesis and characterization of biodegradable copoly(ether-ester-urethane)s and their chitin whisker nanocomposites

A series of copoly(ether-ester-urethane)s have been synthesized from poly(3-hydroxybutyrate) (PHB) diol prepolymer, as hard segments, and copoly(epsilon-caprolactone-ethylene glycol-epsilon-caprolactone) (PCL-PEG-PCL) diols with different PEG block lengths, as soft segments, with/without chitin whiskers (ChW) using hexamethylene diisocyanate, as a coupling agent, in one-step polymerization. The PHB content in the resulting copolymers was 0 and 40 %, and the content of ChW was varied from 0 to 5 %. The chemical structure of the resulting copolymers was characterized by FTIR, H-1-NMR and C-13-NMR spectra. The effect of chemical structure and ChW content on the thermal properties was studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). The DSC data revealed that the Delta H (m) of both PHB and PCL-PEG-PCL slightly increases with increasing the ChW content. The cold and melt crystallization of PHB enhanced with increasing ChW content. The TG data revealed that the thermal stability of copolymers slightly enhanced at high content of ChW. The swelling behavior of the copolymers was also investigated.