研究

Freiburg University researchers develop novel eco-friendly wood-based 3D printing material

森林生物材料部的研究人员弗莱堡大学(UCF) have developed a novel environmentally-friendly wood-based 3D printing material.

The team, headed by UCF’s Professor Marie-Pierre Laborie, combined lignin, a chemical that provides strength to plant cell walls, with cellulose balls to create a novel biosynthetic polymer. As Lignen is produced endlessly by plants to protect themselves from predators, the team’s creation could represent a sustainable new printing material for use within light construction or industrial applications.

The Freiburg researchers used a DIW 3D printing technique (pictured) to test their novel biomaterial. Image via Lisa Ebers, Freiburg University.
The Freiburg researchers used a DIW 3D printing technique (pictured) to test their novel biomaterial. Image via Lisa Ebers, Freiburg University.

Liquid Crystalline Polymer 3D printing materials

液晶聚合物(LCP)是通过与柔性线圈塑料混合的棒状聚合物产生的,是一组完善的强,轻巧的分子复合材料。随着研究开始转向可持续材料的开发,LCP越来越多地与生物聚合物混合在一起,以创建生态友好的树脂。

在今年早些时候弗雷堡团队进行的研究中,他们将Organosolv木质素(OSL)添加到羟丙基纤维素(HPC)中,将木质蛋白插入混合物的效果非常深刻。添加木质可显着提高剪切诱导的瞬态带的稳定性,从而通过剪切铸造来创建强,高度定向的延性膜。

Chemical crosslinking was later found to reinforce the integrity of the OSL-HPC mix, and improve its water solubility drawbacks, but both at the cost of its eco-friendly credentials. As a result, the challenge remains to develop sustainable bio-based crosslinkers that turn the polymers into insoluble Liquid Crystalline polymer (LC) networks.

Previous researchers have managed to achieve further crosslinking via radiation and esterification, but again, these weren’t bio-based solutions. In order to produce an LCE with the desired characteristics, the Freiburg team proposed using polyfunctional carboxylic acids, a known crosslinking agent for carbohydrates, to reinforce the polymer.

Adding lignen to the team's biopolymer mixture was found to make it less soluble or prone to swelling. Image via the ACS Applied Bio Materials journal.
发现在团队的生物聚合物混合物中添加木质,使其不易溶解或易于肿胀。图像通过ACS应用的生物材料杂志。

The Freiburg team’s wood-based biomaterial

与使用剪切铸造过程生产的产品相比,添加剂生产的LCP有望具有更高的方向水平,并且更有效。从一开始,研究人员就开始开发与直接墨水写作(DIW)和融合沉积建模(FDM)3D打印机兼容的材料。

To create their novel lignen-based polymer, the research team dissolved the HPC and OSL powder separately in acetic acid, before storing them in darkness for two days. The solutions were summarily mixed with a constant HPC/OSL ratio of 4:1 (w/w) and kept sealed for another five days. After the crosslinking agents and glycerol-citric acid had been added, the concoction was mixed and centrifuged, yielding the researchers’ 3D printing polymer.

去离子水中的溶解度测试表明,延迟对材料的化学行为产生重大影响。暴露于水中的几分钟内,非固化样品在几分钟内分解,而固化样品完全不溶于溶解,这表明了交联对网络形成的重要性。

后来depo进行流变分析sited filament to assess the structural integrity of 3D printed components during solidification. Results showed that materials containing higher levels of lignen displayed less compliance, which was more conducive to post-printing stability. As a result, lignen, the second most abundant biopolymer in the world, had proven itself as the key ingredient in creating usable and sustainable LCPs.

The Freiburg team concluded that they had successfully demonstrated eco-friendly HPC/OSL blends that, unlike previous LCPs, had a locked supramolecular arrangement. Although the researchers had optimized their solution for 3D printed parts, they conceded that further improvements were needed to solidify the fabricated structures for end-use architectural applications.

Making additive manufacturing more sustainable

A number of universities and organizations are currently working on ways to make 3D printing more environmentally-friendly.

立陶宛的科学家Vilnius Universityand theKaunas University of Technologyhave developed a用于光学3D打印的可回收树脂(O3P). The new biomaterial is designed to move O3DP manufacturing towards bio-based resins, instead of non-recyclable petroleum-derived photopolymers.

equispheres, a metal powder manufacturer, has received $8 million fromSustainable Development Technology Canada(SDTC) to createsustainable 3D printing powders. Independent tests verified that the materials were quicker to produce, and featured improved mechanical performance, compared to conventional powders.

波兰公司AmazeMet已经推出了一个ultrasonic atomizer能够从各种不同的原始材料中产生粉末状的原料。使用该设备,可以轻松地重新处理3D打印垃圾并将其回收为细金属粉末。

The researchers’ findings are detailed in their paper titled “Lignin in Bio-Based Liquid Crystalline Network Material with Potential for Direct Ink Writing,” which was published in the ACS Applied Bio Materials journal. The report was co-authored by F. Robert Gleuwitz, Gopakumar Sivasankarapillai, Gilberto Siqueira, Christian Friedrich and Marie-Pierre G. Laborie.

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Featured image shows the DIW 3D printing technique used by the Freiburg team to assess the integrity of their novel biomaterial. Image via Lisa Ebers, Freiburg University.