Krapež Tomec Daša, Schöflinger Manfred, Leßlhumer Jürgen, Gradišar Centa Urška, Žigon Jure, Kariž Mirko
Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia.
Kompetenzzentrum Holz GmbH, Science Park 2, Altenberger Straße 69, 4040 Linz, Austria.
Polymers (Basel). 2024 Mar 18;16(6):836. doi: 10.3390/polym16060836.
This paper describes the use of microcrystalline cellulose (MCC) as an additive in wood-polylactic acid (PLA) filaments suitable for 3D printing. Filaments prepared with PLA, thermally modified (TM) wood, and three different MCC loadings (1, 3, and 5 wt%) by two-step melt blending in the extruder were characterized with respect to their rheological, thermal, and mechanical response. The analyses demonstrate that a low MCC content (1%) improves the mobility of the polymer chains and contributes to a higher elasticity of the matrix chain, a higher crystallinity, a lower glass transition temperature (by 1.66 °C), and a lower melting temperature (by 1.31 °C) and leads to a higher tensile strength (1.2%) and a higher modulus of elasticity (12.1%). Higher MCC loading hinders the mobility of the polymer matrix and leads to a rearrangement of the crystal lattice structure, resulting in a decrease in crystallinity. Scanning electron micrographs show that the cellulose is well distributed and dispersed in the PLA matrix, with some agglomeration occurring at higher MCC levels. The main objective of this study was to develop and evaluate a filament containing an optimal amount of MCC to improve compatibility between wood and PLA, optimize melt processability, and improve mechanical properties. It can be concluded that a 1% addition of MCC favorably changes the properties of the wood-PLA filaments, while a higher MCC content does not have this effect.
本文描述了微晶纤维素（MCC）作为添加剂在适用于3D打印的木材-聚乳酸（PLA）长丝中的应用。通过在挤出机中两步熔融共混制备了含有PLA、热改性（TM）木材以及三种不同MCC含量（1%、3%和5%重量）的长丝，并对其流变学、热学和力学响应进行了表征。分析表明，低MCC含量（1%）可提高聚合物链的流动性，并有助于提高基体链的弹性、结晶度、降低玻璃化转变温度（降低1.66℃）和熔点（降低1.31℃），并导致更高的拉伸强度（提高1.2%）和更高的弹性模量（提高12.1%）。较高的MCC含量会阻碍聚合物基体的流动性，并导致晶格结构重排，从而导致结晶度降低。扫描电子显微镜照片显示，纤维素在PLA基体中分布良好且分散，在较高MCC含量时会出现一些团聚现象。本研究的主要目的是开发和评估一种含有最佳MCC量的长丝，以改善木材与PLA之间的相容性，优化熔体加工性能，并改善力学性能。可以得出结论，添加1%的MCC有利于改变木材-PLA长丝的性能，而较高的MCC含量则没有这种效果。
