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Cellular, Mineralized, and Programmable Cellulose Composites Fabricated by 3D Printing of Aqueous Pastes Derived from Paper Wastes and Microfibrillated Cellulose
Macromolecular Materials and Engineering ( IF 3.9 ) Pub Date : 2020-03-20 , DOI: 10.1002/mame.201900740
Benjamin Stolz 1 , Rolf Mülhaupt 1
Affiliation  

Combining recycling of paper wastes (WPs) with extrusion‐based additive manufacturing represents a sustainable route to cellular cellulose composites tailored for lightweight construction. Particularly, shear mixing of shredded WPs with an aqueous solution of a polymer binder like polyvinyl alcohol (PVA) yields aqueous pastes suitable for 3D printing. As a shear thinning additive, both WP and microfibrillated cellulose account for enhanced shear thinning and dimensional stability. Opposite to the formation of dense WP/PVA composites by melt extrusion, 3D printing of aqueous pastes produces cellular cellulose/PVA composites exhibiting hierarchical pore architectures. In spite of low densities around 0.8 g cm−3, high Young's modulus (2.0 GPa) and tensile strength (53 MPa) are achieved. Mechanical stability, water resistance, and even flame retardancy simultaneously improve by crosslinking with glyoxal and especially by mineralization. Multimaterial 3D printing combines the 3D dispensing of cellulose/PVA pastes with the simultaneous, staged, or subsequent spraying of aqueous water glass to enable mineralization of composite surface, bulk, and interlayers. Furthermore, the glyoxal‐mediated crosslinking affords thermo‐ and moisture‐responsive cellulose/PVA composites with programmable shape change induced either by heating at 100 °C or by exposure to moisture at 37 °C.

中文翻译:

通过3D打印纸废料和微原纤化纤维素衍生的水性糊料制备的蜂窝,矿化和可编程纤维素复合材料

将纸屑(WP)的回收与基于挤出的增材制造相结合,代表了为轻质建筑量身定制的蜂窝纤维素复合材料的可持续发展之路。特别是,将切碎的WP与聚合物粘合剂(如聚乙烯醇(PVA))的水溶液进行剪切混合,可得到适用于3D打印的水性糊剂。作为剪切稀化添加剂,WP和微纤化纤维素都有助于增强剪切稀化和尺寸稳定性。与通过熔融挤出形成致密的WP / PVA复合材料相反,水性糊剂的3D打印产生具有分级孔隙结构的多孔纤维素/ PVA复合材料。尽管密度较低,但约为0.8 g cm -3,可以获得高的杨氏模量(2.0 GPa)和拉伸强度(53 MPa)。通过与乙二醛交联,尤其是矿化,可同时提高机械稳定性,耐水性,甚至阻燃性。多材料3D打印将纤维素/ PVA浆料的3D分配与同时,分阶段或随后的水性玻璃水喷涂相结合,以实现复合材料表面,整体和中间层的矿化。此外,乙二醛介导的交联可提供对温度和湿度有响应的纤维素/ PVA复合材料,这些复合材料具有可编程的形状变化,该形状变化是通过在100°C下加热或在37°C下暴露于水分引起的。
更新日期:2020-03-20
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