数十万年来,人类一直在使用不同的技术来增加天然木材的强度,但是在最近的开创性中学习, researchers from the University of Maryland unveiled a process that was capable of making wood as hard as steel.
学习:硬化的木材作为钢和塑料的可再生替代品。图片来源:tuasiwatn/shutterstock.com
40%至50%的木材是由纤维素制成的。与许多人造材料(包括金属,聚合物和陶瓷)相比,这种天然材料具有更高的强度密度比。亚博网站下载就其本身而言,木材足够强,可以用作建筑材料,但是加工的木材以增加纤维素与其他成分的比率可以使其更强大。
这项新研究描述了一个两步过程,该过程去除了木材的非纤维素成分。研究人员说,他们特别专注于去除木质素,这是一种结合化合物。去除木质素后,研究团队随后施加热量和压力以去除多余的水。
马里兰州的研究人员通过将太空木块切成小样本开始了他们的过程。然后将样品浸泡在水,氢氧化钠和硫酸钠的溶液中。该溶液填充在木材样品的孔中,使它们沉入固定容器的底部。
The samples were then separated into three different groups. Each sample was boiled at 100 degrees Celsius for either two, four or six hours. The samples were then rinsed to wash off any residual chemicals. At this point in the process, lignin was removed from the wood samples, causing them to be soft to the touch.
在过程的第二阶段,将木材样品放在热压机中,覆盖有纸巾,并在室温下以20 MPa压缩六个小时。然后将样品加热至摄氏100摄氏度约100摄氏度以去除水分。最后,将木材样品放入食品级矿物油48小时中,以形成防水外部。
该团队进行了分析,以比较不同批次的样品,这些样品被浸入化学浴中两个,四个或六个小时。研究人员发现,浸泡的样品的性能要比浸泡的样品要好两到六个小时。
在高分辨率显微镜下进行的检查揭示了两步过程大大减少了木材中孔,间隙,通道和缺陷的数量。这些空间允许树运输水,但也降低了木材的潜在强度。
更具创新性的木材用途 - 圆锥:用木材的形成包装溶液代替塑料
研究研究人员还希望通过使用桌刀来证明其人工硬化的木材的实用性。加工后,将木材样品雕刻成刀的形状,锐化并浸入矿物油中,以形成防水表面。这种外部涂层不仅防止了木刀浸泡水,而且还有助于保持刀的锋利。
The result was a dishwasher-safe table knife that was three times sharper than a standard knife. The study team showed it was able to easily cut through a cooked steak. While wooden cutlery has become a popular green alternative to steel or plasticware, the knife developed by the team was much sharper than anything else available, and 23 times harder than unprocessed wood.
作为进一步的证明,研究团队还用坚硬的木材创造了一个钉子,然后将其撞到木块中。研究人员指出,他们的指甲像钢一样坚硬,但由于水分而耐锈和膨胀。
为什么要切换到硬化的木头?
该研究的结果和两种应用显示,硬化的木材可能是一种便宜,可持续的原材料。由于其强度,塑料和钢非常受欢迎。亚博网站下载但是,每种材料具有有问题的品质。
每年都使用数十亿个塑料器皿。这些器皿的回收工作是零星的,由于它们的尺寸,它们不容易回收。根据研究团队的说法,这些小块塑料需要400多年的时间才能分解在垃圾填埋场中。
进一步阅读:用添加剂制造再生木材废物
Steel and other alloys are stronger than plastic and recyclable. However, these materials involve costly production processes that are energy-intensive. For example, steel production requires a heating process of around 1000 degrees Celsius. Ceramic knives and dishes also require extreme, energy-intensive heat.
Pending a bit more analysis, the process described in the study appears to be much more energy-efficient. It requires a far lower heat of 100 degrees Celsius. Also, the product is far more environmentally friendly than plastic in particular. Furthermore, the study team said the chemical bath could potentially be reused from batch to batch.
Resources and Further Reading
细胞出版社。研究人员制作的坚硬的木刀将牛排切成薄片。EURKALERT。[在线]可用:https://www.eurekalert.org/news-releases/931555
Chen,B。等。硬化的木材作为钢和塑料的可再生替代品。事情。[在线]可用:https://www.sciencedirect.com/science/article/abs/pii/S2590238521004653
Sims,D。研究人员声称要制造比钢更坚硬的木材。TechSpot。[在线]可用:https://www.techspot.com/news/91982-researchers-claim-make-make-wood-tougher-than-than-steel.html
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