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芳纶纳米纤维/丝素蛋白高强度复合膜的结构、性质和应用研究
Alternative Title材料工程
吕莉莉
Thesis Advisor丝素蛋白,芳纶纳米纤维,力学性能,仿生复合,过滤截留膜
2017-05
Degree Grantor中国科学院大学;中科院青岛生物能源与过程研究所
Place of Conferral北京;青岛
Degree Discipline生物体中众多结构均为有机/无机纳米物质杂化而成的复合物,并具有优异的机械、光学及生物学等性质,例如骨骼由羟基磷灰石和胶原蛋白复合而成,木材由木质素和纤维素共同组成等。研究者们基于这种杂化方式,设计并制备了多种基于生物大分子且具有仿生多层次复合结构的功能材料。其中,丝素蛋白(SF)具有来源广泛、机械强度高、生物相容性好、可生物降解等优势,作为新型材料受到关注。为了进一步提高丝素蛋白材料的力学性能,多种合成或天然纳米材料被引入,尤其是纤维态的柔性材料,与丝素蛋白复合后可获得具有仿生多层次结构的高强度复合物。但现有的多数掺杂过程较为复杂,且掺杂物与SF间的相互作用力弱,混合均匀度低,无法获得最优力学性能。基于此,为提高丝素蛋白的机械性能并制备功能材料,本文研究了具有超高强度及高模量的芳纶纳米纤维与丝素蛋白的掺杂效果,并重点讨论了芳纶纳米纤维/丝素蛋白复合膜的结构、力学性能及应用。 首先,将商业化的芳纶(Kevlar)置于NaOH的二甲基亚砜饱和溶液中,酰胺基去质子化得到芳纶纳米纤维(ANF);继而,为增加芳纶纳米纤维的表面官能团数量并提高其与丝素蛋白的相互作用力,通过高温混酸处理,将芳纶纳米纤维进行表面改性,并记为ANF2;改性后的芳纶纳米纤维与丝素蛋白形成的复合膜断裂强度达210.4 MPa,模量达6.25 GPa,相对于纯丝素蛋白膜分别提高了84.1%、84.3%。 丝素蛋白可在一定条件下自组装形成再生蚕丝纳米纤维(RSF)。在丝素蛋白自组装过程中引入改性后的芳纶纳米纤维,由于芳纶纳米纤维和再生蚕丝纳米纤维之间产生较强的相互作用,以此得到的RSF/ANF2复合膜力学性能大幅提升。例如,在芳纶纳米纤维含量为20 wt%时,复合膜强度、断裂伸长率、模量可达52.4 MPa、1.76%和2.27 GPa。 因RSF/ANF2复合膜纳米纤维组成,其表面和内部含有大量孔道,作为过滤截留膜的性能优异,其优秀的力学性能亦能保证其在高压下使用;同时,RSF在蛋白酶作用下可生物降解,复合膜具有良好的生物降解性。RSF/ANF2复合膜的孔径和流通量可通过调节芳纶纳米纤维的掺杂比例、复合膜的厚度等进行调控。 基于RSF/ANF2复合膜优异的强度和柔韧性,复合膜还可作为负载电子元件的柔性基底。利用再生蚕丝纳米纤维辅助还原制备二维金纳米片,在复合膜表面抽滤成图案化导电性回路,展示出复合膜在柔性电极等领域的应用潜力。
Keyword工程硕士
Abstract中文
Other AbstractA variety of biomaterials in living systems rely on hierarchical hybridization of bio-macromolecular with different natural inorganic/organic nanomaterials for incredible mechanical property, optic and biological functions, such as collagen with apatite in bone and cellulose with lignin in wood. These hybridization strategies have inspired to design various functional composites of bio-macromolecules for biomimetic structural hierarchies and desired properties. In particular, silk fibroin has drawn researchers’ attention as advanced materials for its widely available raw material, excellent mechanical property, perfect biocompatibility and controllable biodegradability. To further improve its mechanical properties, many synthetic/natural inorganic nanomaterials with high moduli have been hybridized into regenerated silk fibroin to compete with its strongest analogues, especially biological nanofibrils which were incorporated into silk fibroin for biomimetic structures and higher properties. However, broad applications of these biologic nanofibrils were hindered by their complicated production procedures, limited starting materials and poor intermolecular interaction with bulk filk fibroin. Herein we proposed a biomimetic nanofibrous strategy to incorporate aramid nanofibril (ANF) into silk fibroin for unprecedented properties and discussed the microstructure, mechanical properties and applications of ANF hybridized silk fibroin materias. Following the biomimetic inspiration, commercial Kevlar fibers were first liquid-exfoliated into ANF via deprotonation of amide groups in the solvent of dimethyl sulfoxide (DMSO) saturated with KOH. In order to improve its surface hydrophilicity and adhesion for hybridization of silk, ANF was hydrothermally treated under acidic conditions to introduce functional groups. By optimizing the hydrothermal treating condition and hybridizing compositions of ANF in the final composites of silk fibroin, the fracture strength and elastic moduli ultimate stress could reach to 210.43 MPa, 6.25 GPa for SF/ANF2 composite film, which has enchanced by 184.1% and 184.3% as those of pure silk fibroin. Besides strengthen SF films, ANF could be used to enhance the mechanical properties of regenerated silk nanofibrils (RSF) membranes. Generally, SF molecules self-assemble into elongated RSF through incubating in 7 vol.% ethanol at pH 9.5. And acid treated ANF for 2h, named as ANF2, was used as additives to RSF to enhance the interaction between ANF2 and RSF. The addition of 20 wt% ANF2 is enough to convert the weak and poor pure RSF into free-standing membranes with ultimate stress reached to 52.4 MPa, the strain to 1.76% and Young’s modulus to 2.27 GPa. The free-standing porous RSF/ANF2 membranes with good mechanical properties and stability showed hopeful application in pressure-driven filtration. Additionally, due to the outstanding biocompatibility and biodegradability of silk fibrion, pore size of the composite membranes could be tuned to some extent by enzymatic degradation of silk I and noncrystalline regions in SF. And the separation performance of the RSF/ANF2 membranes could be adjusted through changing the ratio between RSF and ANF2, by varying the membrane thickness. Furthermore, considering their good mechanical property, the RSF/ANF2 composite membranes can also be constructed to flexible electronic devices. Large-size single gold crystal platelets were synthesized with the help of RSF, and the gold nanoplatelets were deposited onto the surface of RSF/ANF2 composite membranes through vacuum filtration with a patterned mold, and showed excellent conductivity as flexible electronic devices.
Department仿生智能材料团队
Date Available4361
Subtype硕士 ; 学位论文
Language中文
Document Type学位论文
Identifierhttp://ir.qibebt.ac.cn/handle/337004/9977
Collection仿生智能材料团队
Affiliation1.中国科学院大学
2.中科院青岛生物能源与过程研究所
Recommended Citation
GB/T 7714
吕莉莉. 芳纶纳米纤维/丝素蛋白高强度复合膜的结构、性质和应用研究[D]. 北京;青岛. 中国科学院大学;中科院青岛生物能源与过程研究所,2017.
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