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Xie X.,CAS Chengdu Institute of Organic Chemistry | Xie X.,University of Chinese Academy of Sciences | Bai W.,CAS Chengdu Institute of Organic Chemistry | Wu A.,CAS Chengdu Institute of Organic Chemistry | And 5 more authors.
Journal of Applied Polymer Science | Year: 2015

To modify the mechanical properties of a poly(L-lactide) (PLLA)/poly(para-dioxanone) (PPDO) 85/15 blend, poly(paradioxanone- co-L-lactide) (PDOLLA) was used as a compatibilizer. The 85/15 PLLA/PPDO blends containing 1-5 wt % of the random copolymer PDOLLA were prepared by solution coprecipitation. Then, the thermal, morphological, and mechanical properties of the blends with different contents of PDOLLA were studied via differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and tensile testing, respectively. The DSC result revealed that the addition of PDOLLA into the blends only slightly changed the thermal properties by inhibiting the crystallization degree of the poly(L-lactide) in the polymer blends. The SEM photos indicated that the addition of 3 wt % PDOLLA into the blend was ideal for making the interface between the PLLA and PPDO phases unclear. The tensile testing result demonstrated that the mechanical properties of the blends containing 3 wt % PDOLLA were much improved with a tensile strength of 48 MPa and a breaking elongation of 214%. Therefore, we concluded that the morphological and mechanical properties of the PLLA/PPDO 85/15 blends could be tailored by the addition of the PDOLLA as a compatibilizer and that the blend containing a proper content of PDOLLA had the potential to be used as a medical implant material. © 2014 Wiley Periodicals, Inc. Source


Xie X.,CAS Chengdu Institute of Organic Chemistry | Xie X.,University of Chinese Academy of Sciences | Bai W.,CAS Chengdu Institute of Organic Chemistry | Bai W.,Zhejiang Engineering Research Center in Biodegradable Medical Materials | And 5 more authors.
Journal of Polymers and the Environment | Year: 2015

Poly(l-lactide) (PLLA) was blended with various contents of poly(para-dioxanone) (PPDO; 5, 10, 15 and 20 wt%) by solution co-precipitation to modify the degradation characteristics of PLLA. As PPDO degrades rapidly, it can be advantageously used in blends with PLLA. The in vitro hydrolytic degradation of the PLLA/PPDO blends was studied by weight loss (WL) analysis, water absorption (WA), the thermal properties, the surface morphology and the mechanical properties of the samples in phosphate-buffered saline (pH 7.44) at 37 °C over 8 weeks. During the degradation process, the WL and WA increased significantly for all blends and a fenestral structure with defects was formed on the surface of blend bars as degradation progressed. Meanwhile, the glass transition temperature (Tg), melting temperature (Tm), tensile strength and breaking elongation of the blends decreased with time, whereas the hydrolysis rate of the blends varied with the blend composition. Compared with PLLA, PLLA/PPDO blends exhibited a higher hydrolysis rate. © 2014, Springer Science+Business Media New York. Source


Zhang X.,CAS Chengdu Institute of Organic Chemistry | Zhang X.,University of Chinese Academy of Sciences | Bai W.,CAS Chengdu Institute of Organic Chemistry | Bai W.,Zhejiang Engineering Research Center in Biodegradable Medical Materials | And 5 more authors.
Bulletin of Materials Science | Year: 2015

Blends of poly(ρ-dioxanone) (PPDO) and poly(L-lactic acid) (PLLA) in different proportions were prepared by solution co-precipitation. The nonisothermal crystallization behaviour of pure PPDO and PPDO/PLLA blends was investigated by differential scanning calorimetry. The Avrami, Ozawa and Mo models were used to analyse the nonisothermal kinetics. The addition of PLLA significantly increases the crystallization peak temperature and crystallinity of PPDO, but has little effect on crystallization half-time. The activation energies of crystallization were calculated using the Kissinger equation. The results suggest that PLLA plays two roles in the nonisothermal crystallization of PPDO; PLLA both promotes the crystallization of PPDO as a nucleating agent and meanwhile restricts the motion of PPDO chains. © Indian Academy of Sciences. Source

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