Controllable Degradation of Poly (trimethylene carbonate) via Self-blending with Different Molecular Weights

Abstract

Blend films of Poly (trimethylene carbonate) (PTMC) homopolymers with different molecular weights were prepared. The in vitro enzymatic degradation tests were carried out in lipase solutions to investigate the effect of self-blending on the degradation performance of PTMC. It was observed that the mass loss decreased as the proportion of low molecular weight PTMC in the blend film increased. And the sample's mass loss with the mass ratio of PTMC334/PTMC57=1/16 reached almost 30% after seven weeks, which corresponded to the minimum degradation rate constant k value of 5.219. It is also indicated by the changes in weight as well as the macroscopic and microscopic morphology. Furthermore, during the degradation cycle, the thickness of the film also became thinner with the mass loss, confirming the surface erosion degradation mechanism of the PTMC blend films. The conclusion that PTMC does not produce acidic degradation products has also been confirmed. Finally, decreases in glass transition temperature (Tg) and thermal stability were found along with the film degraded, attributing to the accumulation of low molecular weight degradation products on the surface. In brief, the long-acting application of PTMC in biomedical fields could be satisfied by precisely tailoring the degradation properties via its self-blending with different molecular weights.