采用熔融共混法制备了纳米氧化锌(ZnO)填充聚乳酸/聚丁二酸丁二酯(PLA/PBS)复合材料。研究了ZnO质量分数对复合材料的力学性能、结晶性能以及动态流变性能的影响。结果表明,随着ZnO含量的增加,复合材料的力学性能和结晶度先升高后降低,...采用熔融共混法制备了纳米氧化锌(ZnO)填充聚乳酸/聚丁二酸丁二酯(PLA/PBS)复合材料。研究了ZnO质量分数对复合材料的力学性能、结晶性能以及动态流变性能的影响。结果表明,随着ZnO含量的增加,复合材料的力学性能和结晶度先升高后降低,当ZnO质量分数为0.5%时,复合材料的拉伸强度和冲击强度分别达到最大值40.99 MPa和8.82 k J/m^2,比未添加ZnO时分别提高了6.3%和28.2%,同时结晶度达到24.4%。动态流变性能测试表明,ZnO的质量分数为0.5%时,复合材料的损耗模量和储能模量均为最大值,反映出此时复合材料内部氢键和交联网络最完善,协同作用效果达到最佳状态,因此力学性能也最优。在ZnO质量分数为0.5%的基础上,采用超临界二氧化碳发泡法对复合材料进行间歇发泡,结果显示添加ZnO的发泡材料泡孔密度比未添加的高出一个数量级,泡孔尺寸分布更加集中,体积膨胀率更高。展开更多
Recently tremendous progress has been evidenced by the advancements in developing innovative three-dimensional(3 D)scaffolds using various techniques for addressing the autogenous grafting of bone. In this work, we de...Recently tremendous progress has been evidenced by the advancements in developing innovative three-dimensional(3 D)scaffolds using various techniques for addressing the autogenous grafting of bone. In this work, we demonstrated the fabrication of porous polycaprolactone(PCL) scaffolds for osteogenic differentiation based on supercritical fluid-assisted hybrid processes of phase inversion and foaming. This eco-friendly process resulted in the highly porous biomimetic scaffolds with open and interconnected architectures. Initially, a 2^3 factorial experiment was designed for investigating the relative significance of various processing parameters and achieving better control over the porosity as well as the compressive mechanical properties of the scaffold. Then, single factor experiment was carried out to understand the effects of various processing parameters on the morphology of scaffolds. On the other hand, we encapsulated a growth factor, i.e., bone morphogenic protein-2(BMP-2), as a model protein in these porous scaffolds for evaluating their osteogenic differentiation. In vitro investigations of growth factor loaded PCL scaffolds using bone marrow stromal cells(BMSCs) have shown that these growth factor-encumbered scaffolds were capable of differentiating the cells over the control experiments. Furthermore, the osteogenic differentiation was confirmed by measuring the cell proliferation, and alkaline phosphatase(ALP) activity, which were significantly higher demonstrating the active bone growth. Together, these results have suggested that the fabrication of growth factor-loaded porous scaffolds prepared by the eco-friendly hybrid processing efficiently promoted the osteogenic differentiation and may have a significant potential in bone tissue engineering.展开更多
The carbon nanotubes（CNTs）/polymethylmethacrylate（PMMA）nanocomposite foams were prepared by the anti-solvent precipitation and supercriticalfoaming method.The morphology and the electricalconductivity of the foams...The carbon nanotubes（CNTs）/polymethylmethacrylate（PMMA）nanocomposite foams were prepared by the anti-solvent precipitation and supercriticalfoaming method.The morphology and the electricalconductivity of the foams with different kinds of CNTs were investigated.The experimentalresults showed that allthe foams had uniform cellstructure,and the cellsize changed from 1.9 to 10 μm when the foaming temperature ranged from 50 ℃ to 95 ℃.With smallcellsize（1.9-4.0 μm）,the conductivities of the foams were 3.34×10^（-6）-4.16×10^（-6） S/cm compared with the solid matrix since the introduction of micro cells did not destroy the conductive network.However,when the cellsize was biger（4.5-10 μm）,the aspect ratio of the CNTs played the dominant role of the conductivity.The foams with short CNTs had higher conductivity,since the short CNTs were hard to stretch and snap by the cells and can well-dispersed in the cellwalland celledges.The results of this work provided a novelmaterialdesign method for conductive foams based on the rule of both microstructure and aspect ratio of the CNTs.展开更多
文摘采用熔融共混法制备了纳米氧化锌(ZnO)填充聚乳酸/聚丁二酸丁二酯(PLA/PBS)复合材料。研究了ZnO质量分数对复合材料的力学性能、结晶性能以及动态流变性能的影响。结果表明,随着ZnO含量的增加,复合材料的力学性能和结晶度先升高后降低,当ZnO质量分数为0.5%时,复合材料的拉伸强度和冲击强度分别达到最大值40.99 MPa和8.82 k J/m^2,比未添加ZnO时分别提高了6.3%和28.2%,同时结晶度达到24.4%。动态流变性能测试表明,ZnO的质量分数为0.5%时,复合材料的损耗模量和储能模量均为最大值,反映出此时复合材料内部氢键和交联网络最完善,协同作用效果达到最佳状态,因此力学性能也最优。在ZnO质量分数为0.5%的基础上,采用超临界二氧化碳发泡法对复合材料进行间歇发泡,结果显示添加ZnO的发泡材料泡孔密度比未添加的高出一个数量级,泡孔尺寸分布更加集中,体积膨胀率更高。
基金supported by the National Natural Science Foundation of China (U1605225, 31570974, and 31470927)the Public Science and Technology Research Funds Projects of Ocean (201505029)+1 种基金the Promotion Program for Young and Middle-aged Teacher in Science and Technology Research of Huaqiao University (ZQN-PY107)the Program for Innovative Research Team in Science and Technology in Fujian Province University
文摘Recently tremendous progress has been evidenced by the advancements in developing innovative three-dimensional(3 D)scaffolds using various techniques for addressing the autogenous grafting of bone. In this work, we demonstrated the fabrication of porous polycaprolactone(PCL) scaffolds for osteogenic differentiation based on supercritical fluid-assisted hybrid processes of phase inversion and foaming. This eco-friendly process resulted in the highly porous biomimetic scaffolds with open and interconnected architectures. Initially, a 2^3 factorial experiment was designed for investigating the relative significance of various processing parameters and achieving better control over the porosity as well as the compressive mechanical properties of the scaffold. Then, single factor experiment was carried out to understand the effects of various processing parameters on the morphology of scaffolds. On the other hand, we encapsulated a growth factor, i.e., bone morphogenic protein-2(BMP-2), as a model protein in these porous scaffolds for evaluating their osteogenic differentiation. In vitro investigations of growth factor loaded PCL scaffolds using bone marrow stromal cells(BMSCs) have shown that these growth factor-encumbered scaffolds were capable of differentiating the cells over the control experiments. Furthermore, the osteogenic differentiation was confirmed by measuring the cell proliferation, and alkaline phosphatase(ALP) activity, which were significantly higher demonstrating the active bone growth. Together, these results have suggested that the fabrication of growth factor-loaded porous scaffolds prepared by the eco-friendly hybrid processing efficiently promoted the osteogenic differentiation and may have a significant potential in bone tissue engineering.
基金Funded by the National Natural Science Foundation of China(51572208)the Natural Science Foundation of Hubei Province(2014CFB258)+1 种基金the Fundamental Research Funds for the Central Universities(WUT:2015III059)111 Project(B13035)
文摘The carbon nanotubes（CNTs）/polymethylmethacrylate（PMMA）nanocomposite foams were prepared by the anti-solvent precipitation and supercriticalfoaming method.The morphology and the electricalconductivity of the foams with different kinds of CNTs were investigated.The experimentalresults showed that allthe foams had uniform cellstructure,and the cellsize changed from 1.9 to 10 μm when the foaming temperature ranged from 50 ℃ to 95 ℃.With smallcellsize（1.9-4.0 μm）,the conductivities of the foams were 3.34×10^（-6）-4.16×10^（-6） S/cm compared with the solid matrix since the introduction of micro cells did not destroy the conductive network.However,when the cellsize was biger（4.5-10 μm）,the aspect ratio of the CNTs played the dominant role of the conductivity.The foams with short CNTs had higher conductivity,since the short CNTs were hard to stretch and snap by the cells and can well-dispersed in the cellwalland celledges.The results of this work provided a novelmaterialdesign method for conductive foams based on the rule of both microstructure and aspect ratio of the CNTs.
