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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. [ABSTRACT FROM AUTHOR]

Bi2NiTiO6 compound which shows both magnetic (TM = 58 K) and ferroelectric properties (TC = 513 K) was synthesized under high pressure of 5 GPa and temperature of 1273 K. The crystal structure, as determined by X-ray powder diffraction and neutron powder diffraction, is a distorted A(B1B2)O3 type perovskite with space group Pn21a. Structural evolution of multiferroic Bi2NiTiO6 shows that there are two isostructural phase transitions at ∼2 GPa and ∼15 GPa under high pressure and at room temperature and indicates that isostructural phase transitions occurred with temperature higher than 823 K under ambient condition. All the isostructural phase transitions come from the Bi ion discontinuous shift, which identifies the phase transition at ∼15 GPa and at temperature higher than 823 K are the same. Using a modified high-T Birch-Murnaghan equation of state and a thermal-pressure approach, we have derived the thermoelastic parameters of high pressure phase Bi2NiTiO6, including the ambient bulk modulus K0, temperature derivative of bulk modulus at constant pressure, volumetric thermal expansivity, pressure derivative of thermal expansion, and temperature derivative of bulk modulus at constant volume. [ABSTRACT FROM AUTHOR]

This study demonstrates a dramatic improvement in the mechanical characteristics of PLGA by blending with PTMC. The addition content of 1 wt% PTMC to PLGA matrix had the highest tensile strength and tensile modulus, the values were 57.46 MPa and 1.06 GPa respectively. It is shown that the interfacial compatibility between the component polymers contributes to the formation of super- tough PLGA materials. The result of the FTIR showed that there was no chemical reaction between the two polymers. The thermal stability of blends was slightly reduced, comparing with the PLGA. Crystallization morphology of PLGA/PTMC composites was spherulite. The degradation properties of PLGA/PTMC composites were studied initially after soaking in PBS. The intrinsic viscosity of samples decreased with respect to the soaking time, mass loss decreased more remarkable at 8 weeks, and the tensile strength could maintain 4 weeks. All the results suggested that the PLGA/PTMC composites might develop a novel material to be used as bone repair materials in the future. [ABSTRACT FROM AUTHOR]