Preparation of multiblock copolymers of poly(p-dioxanone) and polylactide by chain extending

A series of multiblock copolymers based on poly(p-dioxanone) (PPDO) and polylactide tPLA) with different compostions have been synthesized via two steps. A typical produce is showed as follows: dihydroxyl-terminated PPDO and dihydroxyl-terminated PLA homopolymers are synthesized respectively firstly, then the two prepolymers are combined with HDI. The structure of copolymers were characterized by 1H-NMR spectra. High inherent-viscosity chain-extending products can be obtained under optimal reaction conditions. The resulting products have good mechanical properties. The tensile strength of the copolymers increases with the incresase of PLA contents, however, the compositions of multiblock copolymers have no obvious effect on the elongation at break.