Despite polylactide (PLA) representing one of the most promising biodegradable materials, its applications lag far behind owing to the disadvantages of inherent brittleness and flammability, which is challengeable to simultaneously overcome. In this work, a phosphorus-containing core-shell starch nanoparticle (FR-CSS) was synthesized via soap-free emulsion polymerization for concurrent improvement of toughness and flame retardancy of PLA. The results revealed that with the incorporation of 10 wt% FR-CSS, the elongation at break of PLA/10FR-CSS was prominently improved to 308% while the tensile strength was about 40.0 MPa. Particularly, the toughness of PLA/FR-CSS was as high as 108.2 MJ/m 3 , which was 48 times higher than that of neat PLA. Besides, the PLA/10FR-CSS exhibited improved flame retardancy with a UL-94 V-2 rating and a LOI value of 24.5%. These results established an integrated design strategy of incorporating phosphorus-containing core-shell nanoparticles to prepare PLA composites combined excellent toughness with enhanced flame retardancy, therefore broadening the application gallery of PLAs.
Song Lianjun,Zhi Junli,Zhang Pingan,Zhao Qiuyan,Li Ning,Qiao Mingwu,Liu Jie
In this study, a new method was developed to produce biodegradable material using soy protein isolate (SPI) as matrix. The blend films were successfully prepared by casting the aqueous dispersions of SPI and polyamic acid salt (PAS) solution. The effects of blending and PAS content on the structure of the resultant films were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) analyses, scanning electron microscopy (SEM). Furthermore, film thickness, water vapor permeability (WVP), water barrier and mechanical properties were measured. The result showed that there exists strong intermolecular interactions between SPI and PAS, which played an important role in forming a homogeneous structure of the blend films. Moreover, the incorporation of PAS enhanced the water barrier and mechanical properties of the films. This is a simple way to prepare biodegradable films compared with other methods and the blend films have the potentiality to be used as food packaging and biomedical materials instead of synthetic polymer.
Zinc (Zn)-based alloys have been considered potential biodegradable materials for medical applications due to their good biodegradability and biocompatibility. However, the insufficient mechanical properties of pure Zn do not meet the requirements of biodegradable implants. In this study, we have developed a biodegradable Zn−3Mg−0.7Mg 2 Si composite fabricated by high-pressure solidification. Microstructural characterization revealed that the high-pressure solidified (HPS) composite exhibited uniformly distributed fine MgZn 2 granules in an α-Zn matrix. Comprehensive tests indicated that the HPS composite exhibited exceptionally high compression properties including a compressive yield strength of 406.2 MPa, an ultimate compressive strength of 1181.2 MPa, and plastic deformation up to 60% strain without cracking or fracturing. Potentiodynamic polarization tests revealed that the HPS composite showed a corrosion potential of −0.930 V, a corrosion current density of 3.5 μA/cm 2 , and a corrosion rate of 46.2 μm/y. Immersion tests revealed that the degradation rate of the HPS composite after immersion in Hanks’ solution for 1 month and 3 months was 42.8 μm/y and 37.8 μm/y, respectively. Furthermore, an extract of the HPS composite exhibited good cytocompatibility compared with as-cast (AC) pure Zn and an AC composite at a concentration of ≤25%. These results suggest that the HPS Zn−3Mg−0.7Mg 2 Si composite can be anticipated as a promising biodegradable material for orthopedic applications .
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