Effect of poly(lactic-co-glycolic acid) blend ratios on the hydrolytic degradation of poly(para-dioxanone)

The poly(para-dioxanone) (PPDO) was blended with various contents of poly(lactic-co-glycolic acid) (PLGA) (10wt%, 20wt%, 30wt%) by solution co-precipitation in this study. The advantage of PLGA is derived from its safety and low cost. The hydrolytic degradation of PPDO / PLGA blends in vitro was studied by weight loss, water absorption, thermal properties, surface morphology, and mechanical properties in phosphate-buffered saline (pH = 7.44) at 37 ℃ for 8 weeks. After degradation, the weight loss and water absorption of all blends increased significantly. PPDO/PLGA (70/30) showed the largest weight loss during the whole degradation period. With the prolongation of hydrolysis degradation time, higher crystallinity of the PPDO was attributed to the chain breakage of unstable ester bonds. A fenestral structure with defects was formed on the surface of the blend bars with degradation. Besides, the glass transition temperature (Tg), the melting temperature (Tm), tensile strength, and breaking elongation of the blends decreased with the hydrolysis rate varying with the blend composition. Compared with pure PLGA and pure PPDO, the PPDO/PLGA blends exhibited a higher hydrolysis rate because of poor miscibility. Therefore, PPDO/PLGA blends with tailored degradation times have a lot of potential as a biomaterial for biomedical applications, such as high-performance absorbable sutures or a filler for ameliorating facial wrinkles.