Transparent Poly(methyl methacrylate) Composites Based on Bacterial Cellulose Nanofiber Networks with Improved Fracture Resistance and Impact Strength
Transparent Poly(methyl methacrylate) Composites Based on Bacterial Cellulose Nanofiber Networks with Improved Fracture Resistance and Impact Strength
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DOI：
10.1021/acsomega.9b00388
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发表时间：
2019-06-01
期刊：
影响因子：
4.1
通讯作者：
Lee, Koon-Yang
中科院分区：
文献类型：
--
作者：
Santmarti, Alba;Teh, Jia Wei;Lee, Koon-Yang
纤维素纳米纤维通常被探索作为用于生产高性能复合材料的生物基增强材料。在这项工作中，我们制作了透明的聚（甲基丙烯酸甲酯）（PMMA）复合材料的二维和三维细菌纤维素（BC）的纳米网络。制备并研究了三种不同的复合材料设计，包括1体积%的BC负载：（i）具有均匀嵌入整个PMMA基质的三维BC-PMMA网络的复合材料;（ii）由夹在两个纯PMMA片之间的三维BC-PMMA组成的三维BC-PMMA结构的构造;以及（iii）嵌入PMMA基质中的干燥和良好固结的二维BC-PMMA网络。所有制备的模型BC-PMMA复合材料被认为是光学透明的，但由二维BC网络组成的PMMA复合材料具有更高的透光率（73%@550 nm）相比，三维BC网络对应物（63%@550 nm）。这是由于三维BC网络的比表面积更高，导致更多的光散射。尽管如此，人们发现，二维和三维的BC纤维网作为优异的硬化剂的PMMA基体，提高了所得复合材料的拉伸模量高达30%。然而，没有观察到拉伸强度的改善。使用三维BC-PMMA网络导致基体脆化，降低了所得到的BC-PMMA复合材料的断裂拉伸应变、抗断裂性和夏比冲击强度。当BC碳纤维网络用作二维增强体时，观察到裂纹通过BC碳纤维网络的脱粘扩展，导致更高的断裂韧性和夏比冲击强度。这些新的发现可能会打开进一步的机会，在设计新的光学透明的聚合物复合材料层压板的基础上的二维BC的冲击保护网络。
Cellulose nanofibers are often explored as biobased reinforcement for the production of high-performance composite materials. In this work, we fabricated transparent poly(methyl methacrylate) (PMMA) composites consisting of two-dimensional and three-dimensional bacterial cellulose (BC) nanofiber networks. Three different composite designs consisting of 1 vol % BC loading were fabricated and studied: (i) composites with a three-dimensional BC nanofiber network embedded uniformly throughout the PMMA matrix; (ii) sandwich-structured construction consisting of three-dimensional BC-PMMA sandwiched between two neat PMMA sheets; and (iii) dried and well-consolidated two-dimensional BC nanofiber network embedded in a PMMA matrix. All fabricated model BC-PMMA composites were found to be optically transparent, but PMMA composites consisting of the two-dimensional BC nanofiber network possessed higher light transmittance (73% @550 nm) compared to the three-dimensional BC nanofiber network counterparts (63% @550 nm). This is due to the higher specific surface area of the three-dimensional BC nanofiber network, which led to more light scattering. Nevertheless, it was found that both two-dimensional and three-dimensional BC nanofiber networks serve as excellent stiffening agents for PMMA matrix, improving the tensile modulus of the resulting composites by up to 30%. However, no improvement in tensile strength was observed. The use of three-dimensional BC nanofiber network led to matrix embrittlement, reducing the tensile strain-at-failure, fracture resistance, and Charpy impact strength of the resulting BC-PMMA composites. When the BC nanofiber network was used as two-dimensional reinforcement, cracks were observed to propagate through the debonding of BC nanofiber network, leading to higher fracture toughness and Charpy impact strength. These novel findings could open up further opportunities in the design of novel optically transparent polymeric composite laminates based on the two-dimensional BC nanofiber network for impact protection.