生物降解PHBV共混体系的制备与性能研究
发布时间：2019-02-26 13:53
【摘要】：支架材料作为承载组织工程细胞外基质功能的载体,其结构与性能直接决定了细胞培育、繁殖与分化及组织再生情况。研究和开发具有理想结构特征并能有效满足性能需求的支架材料,对推动组织工程研究的深化具有重要的研究和工程应用价值。生物可降解高分子材料PHBV以其优异的力学性能和生物相容性受到了研究学者和产业界的广泛重视,并成为聚合物成型加工工程领域的一个研究热点。然而,脆性、低热稳定性和成型加工窗口较窄等问题限制了其进一步的广泛应用。本文拟采用熔融共混法、通过复合工业化生产的低成本生物降解高分子材料,系统研究PHBV基共混/复合材料体系的形态结构、结晶性能、力学性能、热性能、流变特性和发泡性能等,探究具有优异综合性能PHBV基可完全生物降解材料的制备方法,及在拉伸形变下的结构与性能演变规律。据此,本文做了以下四个方面的研究工作:(1)采用熔融共混法制备了不同配比的PHBV/PBAT共混材料,系统表征和研究了其微观结构与性能。研究发现,PBAT的加入抑制了 PHBV的结晶,提高了 PHBV基体的热稳定性;随着PBAT含量的增加,共混体系的储能模量、损耗模量及复数黏度均有所提高;PHBV与PBAT两相互不相容,当两相的占比均等时,呈现出共连续相结构;PHBV/PBAT共混物的弹性模量及拉伸强度随着PBAT含量的增加呈现下降趋势,但断裂应变明显改善,当PHBV含量达到75%时,PHBV/PBAT共混物的应变高达1000%仍未断裂。(2)开展了无机纳米粒子羟基磷灰石(HA)增强PHBV/PBAT共混体系的制备及性能研究。研究结果表明,HA的加入使得共混物的晶粒尺寸呈现减小趋势;HA的增强效果取决于其在PHBV/PBAT基体中的分散情况,在PHBV/PBAT/HA(50/50/HA)试样中,HA聚集在相界面处,加剧了两相分离;复合HA后共混体系的弹性模量增加,但拉伸强度和断裂应变有所降低;较好的分散于PBAT相中的HA在间歇发泡过程中起到成核剂作用,促进泡孔成核。(3)在PHBV/PBAT(50/50)二元共混物的基础上,引入生物可降解材料PLA,探究PHBV/PBAT/PLA三元共混体系的性能变化规律及大形变条件。结果表明,随着体系中PLA含量的增加,共混物的热稳定性能提高,各相的分散更加均匀,力学性能提升。PHBV/PBAT/PLA(35/35/30)试样在室温下的弹性模量达645MPa,屈服强度28MPa,断裂应变达到13%。在60℃条件下,(35/35/30)试样具有单轴拉伸下的大变形能力。(4)系统研究了 PHBV/PBAT/PLA(35/35/30)共混物在不同拉伸速率及拉伸比下的应力应变行为及结构演变。拉伸过程中,试样经历裂纹、孔洞的形成与扩展,最后演变为高度取向的纤维状单相体结构。试样的结晶度在总体上随着应变的增加呈现先增大后降低的现象。研究发现,在低应变速率下材料出现应力波动现象,并随着拉伸速率的增加逐渐消失。
[Abstract]:As a carrier of extracellular matrix function in tissue engineering, the structure and properties of scaffolds directly determine cell culture, reproduction, differentiation and tissue regeneration. The research and development of scaffolds which have ideal structural characteristics and can effectively meet the needs of performance have important research and engineering application value in promoting the deepening of tissue engineering research. Because of its excellent mechanical properties and biocompatibility, biodegradable polymer material PHBV has been paid more and more attention by researchers and industry, and has become a research hotspot in the field of polymer molding engineering. However, brittleness, low thermal stability and narrow forming window limit its further application. In this paper, the morphology, crystallization, mechanical properties and thermal properties of PHBV-based blends / composites were systematically studied by means of melt blending method and low-cost biodegradable polymer materials. The rheological properties and foaming properties of PHBV-based biodegradable materials with excellent comprehensive properties were investigated. The evolution of structure and properties under tensile deformation was also investigated. Accordingly, the following four aspects of research work have been done in this paper: (1) PHBV/PBAT blends with different ratios were prepared by melt blending method, and their microstructure and properties were characterized and studied systematically. It was found that the addition of PBAT inhibited the crystallization of PHBV and improved the thermal stability of PHBV matrix, and the storage modulus, loss modulus and complex viscosity of the blend increased with the increase of PBAT content. PHBV and PBAT are incompatible with each other. When the proportion of the two phases is equal, they show the structure of co-continuous phase. The elastic modulus and tensile strength of PHBV/PBAT blends decreased with the increase of PBAT content, but the fracture strain improved obviously. When the content of PHBV reached 75%, the tensile strength of the blends decreased. The strain of PHBV/PBAT blends was as high as 1000%. (2) the preparation and properties of inorganic nano-hydroxyapatite (HA) reinforced PHBV/PBAT blends were studied. The results show that the grain size of the blend decreases with the addition of HA. The strengthening effect of HA depends on its dispersion in PHBV/PBAT matrix. In PHBV/PBAT/HA (50/50/HA) samples, HA aggregates at the interface of phase, which aggravates the two-phase separation. After composite HA, the elastic modulus of the blend increased, but the tensile strength and fracture strain decreased. The better dispersed HA in PBAT phase plays the role of nucleating agent in intermittent foaming process, and promotes cellular nucleation. (3) on the basis of PHBV/PBAT (50 / 50) binary blend, biodegradable material PLA, is introduced. The property change rule and large deformation condition of PHBV/PBAT/ PLA ternary blend system were studied. The results show that with the increase of PLA content, the thermal stability of the blends increases, the dispersion of each phase is more uniform, and the mechanical properties of the blends are improved. The elastic modulus of PHBV / PBAT/PLA (35-35-30) samples reaches 645 MPA at room temperature. The yield strength is 28 MPA and the fracture strain is 13%. At 60 鈩，
本文编号：2430835
[Abstract]:As a carrier of extracellular matrix function in tissue engineering, the structure and properties of scaffolds directly determine cell culture, reproduction, differentiation and tissue regeneration. The research and development of scaffolds which have ideal structural characteristics and can effectively meet the needs of performance have important research and engineering application value in promoting the deepening of tissue engineering research. Because of its excellent mechanical properties and biocompatibility, biodegradable polymer material PHBV has been paid more and more attention by researchers and industry, and has become a research hotspot in the field of polymer molding engineering. However, brittleness, low thermal stability and narrow forming window limit its further application. In this paper, the morphology, crystallization, mechanical properties and thermal properties of PHBV-based blends / composites were systematically studied by means of melt blending method and low-cost biodegradable polymer materials. The rheological properties and foaming properties of PHBV-based biodegradable materials with excellent comprehensive properties were investigated. The evolution of structure and properties under tensile deformation was also investigated. Accordingly, the following four aspects of research work have been done in this paper: (1) PHBV/PBAT blends with different ratios were prepared by melt blending method, and their microstructure and properties were characterized and studied systematically. It was found that the addition of PBAT inhibited the crystallization of PHBV and improved the thermal stability of PHBV matrix, and the storage modulus, loss modulus and complex viscosity of the blend increased with the increase of PBAT content. PHBV and PBAT are incompatible with each other. When the proportion of the two phases is equal, they show the structure of co-continuous phase. The elastic modulus and tensile strength of PHBV/PBAT blends decreased with the increase of PBAT content, but the fracture strain improved obviously. When the content of PHBV reached 75%, the tensile strength of the blends decreased. The strain of PHBV/PBAT blends was as high as 1000%. (2) the preparation and properties of inorganic nano-hydroxyapatite (HA) reinforced PHBV/PBAT blends were studied. The results show that the grain size of the blend decreases with the addition of HA. The strengthening effect of HA depends on its dispersion in PHBV/PBAT matrix. In PHBV/PBAT/HA (50/50/HA) samples, HA aggregates at the interface of phase, which aggravates the two-phase separation. After composite HA, the elastic modulus of the blend increased, but the tensile strength and fracture strain decreased. The better dispersed HA in PBAT phase plays the role of nucleating agent in intermittent foaming process, and promotes cellular nucleation. (3) on the basis of PHBV/PBAT (50 / 50) binary blend, biodegradable material PLA, is introduced. The property change rule and large deformation condition of PHBV/PBAT/ PLA ternary blend system were studied. The results show that with the increase of PLA content, the thermal stability of the blends increases, the dispersion of each phase is more uniform, and the mechanical properties of the blends are improved. The elastic modulus of PHBV / PBAT/PLA (35-35-30) samples reaches 645 MPA at room temperature. The yield strength is 28 MPA and the fracture strain is 13%. At 60 鈩，
本文编号：2430835
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