Synthesis and characterizaton of block tercopolymer and degradation behavior of their nano-structured fibers via electrospinning

Biodegradable block tercopolymers were synthesized by bulk ring-opening copolymerization of trimethylene carbonate (TMC), l-lactide (LLA) and ε-caprolactone (ε-CL) at different feed molar ratios. The molecular structure of the tri-block copolymer was confirmed by 1H NMR, 13C NMR and FT-IR analysis. Nano-structured fibers of the obtained tri-block tercopolymers were prepared by electrospinning technique. XRD spectra of the nanofibers showed that the polymer chain orientation enhanced and the crystallinity increased during the electrospinning process. The mechanical properties of the nano-structured fibers can be adjusted by changing the compositions of the copolymers. The biodegradability of the nanofibers was investigated by intrinsic viscosity change and SEM photos. The viscosity of the nanofibers, which derived from the tri-block copolymers, decreased gradually with degradation time. The SEM photos showed that the morphology change of the tri-block copolymers was related to the composition of the copolymer after the degradation time of 225 days.