A new generation of materials scientists is developing sustainable materials – and methods for making them – in response to warnings of an imminent climate catastrophe. Natural and plant-based composite materials are gaining traction, but can they replace traditional alternatives?
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Pioneers in both research and industry are working to prove that, in fact, plant-based composites can replace traditional, unsustainable materials. A team from the Massachusetts Institute of Technology (MIT) recently engineered a plant-based composite made with polymer and cellulose nanocrystals (the structures that make trees and other plants so strong.)
Meanwhile, the largest ever natural fiber composite structure – a nacelle for an offshore wind turbine – was installed by Dutch shipbuilders绿船in the Harbor of Rotterdam, Netherlands, in summer 2021.
我们需要一种新的材料制造方法欧洲杯足球竞彩
Plant-based and natural composite materials are being developed in response to increasing demand for environmentally friendly, sustainable, and biodegradable composites.
这种需求来自对环境的意识，监管和义务的日益增加，以及鲁ck耗资资源的制造和建立活动将破坏维持地球文明的平衡生态系统。
自然纤维在整个复合行业已经建立了良好的纤维。在过去的几十年中，他们在众多研究中表现出了出色的理化和机械性能。
These properties combine with good biodegradability (they decompose without releasing toxins into the environment), biocompatibility (they can be used safely in animal bodies), and renewable sourcing (materials can be grown again in a realistic timeframe, unlike oil for plastic which takes millions of years to form underground.)
天然纤维可能来自矿物或动物来源，但植物性纤维是迄今为止最相关的。与天然丝（需要大量能量和淡水提取）等动物纤维不同，植物性纤维实际上是从生产到寿命末生命的可持续材料。欧洲杯足球竞彩基于植物的纤维比基于动物的纤维更经济，通常具有生物相容性，与未经处理的动物或矿物基纤维不同。
在许多情况下，在许多复合应用中，基于植物的纤维已经取代了用玻璃，碳和芳香剂制成的纤维增援。汽车，航空航天，服装和制药扇区都在不同程度上包含植物性纤维。
The Latest Development in Plant-Based Composites: Cellulose Nanocrystals
纤维素is a naturally occurring – and abundant – polymer. It is the main structural component of all algae and plants. Each cellulose fiber contains reinforcing cellulose nanocrystals, called CNCs, which arrange themselves in a crystal-like nanostructure.
CNCs form the walls of plants’ microscopic cells and provide plants with considerable strength. They are both stronger and stiffer than Kevlar, and researchers believe they can be applied to make strong plastics that are produced sustainably.
In the last few years, scientists developed a method for extracting CNCs using acid hydrolysis. But incorporating the crystals into composite materials at large quantities has remained challenging: the CNCs tend to clump up and only bond weakly with the substrate material.
塑料替代品：我们现在在哪里？
麻省理工学院科学家的新研究描述了包含大部分CNC的复合材料，并结合了合成聚合物。该复合材料比骨骼强，更坚固，比标准铝合金更坚硬。这项由麻省理工学院机械工程教授约翰·哈特（John Hart）监督的研究发表在《杂志》上纤维素in 2022.
The team mixed commercially available powdered CNC with a synthetic polymer in a ratio that would result in a gel solution. The viscosity of the solution was tuned so that the team could feed it through a 3D printer’s extrusion nozzle, or pour it into a cast as in conventional composite layering.
使用超声探针将结合CNC分散在凝胶中，增加了与聚合物底物分子强烈键合的单个晶体的机会。所得的材料在复合材料混合物中最多使用90％的CNC，这是迄今为止复合材料中CNC的最高比率。
首席研究员Abhinav Rao博士在哈特的监督下工作的学生说：
“我们基本上是解构木材，并重建了木材。我们采用了木制纳米晶体的最佳组成部分，并重建它们以实现新的复合材料。”
风能中的植物复合材料
可再生风能可能是未来净零碳经济的主要贡献者，但是它对世界可持续性目标的贡献受到风力涡轮机制造中能源密集型，不可回收的，不可降解的材料的限制。欧洲杯足球竞彩
对刀片等风力涡轮机组件的高工程要求 - 它们必须非常大，非常轻巧且非常强大 - 使这一挑战性。但是，荷兰造船厂Green Boots最近正面采取了挑战。
2021年夏季，有史以来第一个天然纤维复合纳塞尔（Nacelle来自风产生的旋转的电能。
鹿特丹的7.3 m绿色NACELLE安装在600 kW风力涡轮机的转子（直径为44 m）上，并满足正在进行的工程检查。它不仅是有史以来最大的Nacelle，它是有史以来最大的天然纤维复合结构。
复合材料的未来是基于植物的吗？
目前，MIT的CNC复合材料和绿船基于植物的NaCelle之类的例子处于可持续材料研究和应用的最前沿。欧洲杯足球竞彩但是，该领域在学术界和行业中都在迅速扩展，替代方案的需求变得越来越清楚。
Industry needs to adopt these new technologies at scale, and soon. Researchers, policymakers, and the consuming public can all accelerate this adoption by feeding more knowledge, guidelines, and demand for a better way to make materials back to industry.
参考和进一步阅读
Chu, J. (2022).New plant-derived composite is tough as bone and hard as aluminum。麻省理工学院。[在线]可用：https://news.mit.edu/2022/plant-derived-composite-0210
Pilkington, B. (2021).The First-Ever Natural Fiber Composite Nacelle for Offshore Wind Turbines。偶氮清洁技术。[在线]可用：https://www.azocleantech.com/article.aspx?articleId=1196
Rao, A., Divoux, T., Owens, C.E.,等。（2022）。可打印的，可铸的，纳米晶纤维素 - 环氧复合材料，表现出分层nacre样强化。纤维素。可用网址：https://doi.org/10.1007/s10570-021-04384-7
Syduzzaman，M.，M.，Abdullah Al Faruque，K。Bilisik和M. Naebe（2020）。基于植物的天然纤维增强复合材料：制造，特性和应用的综述。涂料。可用网址：https://doi.org/10.3390/coatings10100973
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