Graupner Nina, Müssig Jörg
HSB-Hochschule Bremen, the Biological Materials Group, Department of Biomimetics, Neustadtswall 30, D-28199 Bremen, Germany.
Biomimetics (Basel). 2024 Feb 21;9(3):131. doi: 10.3390/biomimetics9030131.
Bast fibre-reinforced plastics are characterised by good strength and stiffness but are often brittle due to the stiff and less ductile fibres. This study uses a biomimetic approach to improve impact strength. Based on the structure of the spicules of a deep-sea glass sponge, in which hard layers of bioglass alternate with soft layers of proteins, the toughness of kenaf/epoxy composites was significantly improved by a multilayer structure of kenaf and cellulose acetate (CA) foils as impact modifiers. Due to the alternating structure, cracks are deflected, and toughness is improved. One to five CA foils were stacked with kenaf layers and processed to composite plates with bio-based epoxy resin by compression moulding. Results have shown a significant improvement in toughness using CA foils due to increased crack propagation. The unnotched Charpy impact strength increased from 9.0 kJ/m of the pure kenaf/epoxy composite to 36.3 kJ/m for the sample containing five CA foils. The tensile and flexural strength ranged from 74 to 81 MPa and 112 to 125 MPa, respectively. The tensile modulus reached values between 9100 and 10,600 MPa, and the flexural modulus ranged between 7200 and 8100 MPa. The results demonstrate the successful implementation of an abstract transfer of biological role models to improve the toughness of brittle bast fibre-reinforced plastics.
韧皮纤维增强塑料具有良好的强度和刚度，但由于纤维坚硬且延展性较差，往往比较脆。本研究采用仿生方法来提高冲击强度。基于深海玻璃海绵骨针的结构，其中生物玻璃硬层与蛋白质软层交替排列，通过将红麻与醋酸纤维素（CA）箔片作为冲击改性剂的多层结构，显著提高了红麻/环氧树脂复合材料的韧性。由于这种交替结构，裂纹发生偏转，韧性得以提高。将一到五层CA箔片与红麻层堆叠，并通过模压成型加工成含生物基环氧树脂的复合板。结果表明，由于裂纹扩展增加，使用CA箔片后韧性有显著提高。无缺口夏比冲击强度从纯红麻/环氧树脂复合材料的9.0 kJ/m提高到含五层CA箔片样品的36.3 kJ/m。拉伸强度和弯曲强度分别在74至81 MPa和112至125 MPa之间。拉伸模量达到9100至10600 MPa之间的值，弯曲模量在7200至8100 MPa之间。结果表明，成功实现了将生物模型进行抽象转化以提高脆性韧皮纤维增强塑料的韧性。
