A Biodegradable and Cross-Linkable Multiblock Copolymer Consisting of Poly(propylene fumarate) and Poly(ε-caprolactone): Synthesis, Characterization, and Physical Properties

In an effort to develop various controllable biomaterials, a series of novel cross-linkable and biodegradable multiblock poly(propylene fumarate-co-caprolactone) [P(PF-co-CL)] copolymers have been synthesized via a three-step polycondensation of oligomeric polypropylene fumarate (PPF) with polycaprolactone (PCL) diols. The chemical structures of 15 copolymers with various PCL compositions and segment lengths were further characterized by FTIR, 1H NMR, and 13C NMR spectra. Their physical and rheological properties have been determined extensively. The composition dependences of various characteristic temperatures such as glass transition temperature Tg, melting temperature Tm, and thermal degradation temperature Td were demonstrated using a phase diagram. Together with DSC results, polarized optical microscopical graphs of several copolymers with high PCL compositions show spherulite crystalline structure. Particularly a banded spherulite has been found for a copolymer with a PCL composition of 87% when it...