Nanocrystals Isolated From Cellulose Have Unique Properties

Biological Strategy

Plants

Natalie Chen

Manage Tension

When a living system is under tension, it means there is a force pulling on it, like a person pulling on a rope tied to a horse. When applied to a living system, unless the system is completely rigid, the result is that it gets stretched. If stretching exceeds the strength of the living system’s material, it can damage it. Living systems manage tension using materials that are flexible and stretchable enough to survive most tension that occurs in their environment. The ocean’s intertidal zone offers a good example. The waves and incoming and outgoing tides put tension on soft-bodied organisms. Mussels resist tension with flexible threads that hold them onto rocks; in contrast, large algae have stretchy fronds.

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Manage Compression

When a living system is under compression, there is a force pushing on it, like a chair with a person sitting on it. When evenly applied to all sides of a living system, compression results in decreased volume. When applied on two sides, it results in deformation, such as when pushing on two sides of a balloon. This deformation can be temporary or permanent. Because living systems must retain their most efficient form, they must ensure that any deformation is temporary. Managing compression also provides an opportunity to lessen the effects of other forces. Living systems have strategies to help prevent compression or recover from it, while maintaining function. For example, African elephant adults weigh from 4,700 to 6,048 kilograms. Because they must hold all of that weight on their four feet, the tissues of their feet have features that enable compression to absorb and distribute forces.

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Plants

Phylum Plantae (“plants”): Angiosperms, gymnosperms, green algae, and more

Plants have evolved by using special structures within their cells to harness energy directly from sunlight. There are currently over 350,000 known species of plants which include angiosperms (flowering trees and plants), gymnosperms (conifers, Gingkos, and others), ferns, hornworts, liverworts, mosses, and green algae. While most get energy through the process of photosynthesis, some are partially carnivores, feeding on the bodies of insects, and others are plant parasites, feeding entirely off of other plants. Plants reproduce through fruits, seeds, spores, and even asexually. They evolved around 500 million years ago and can now be found on every continent worldwide.

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Nanocrystals isolated from cellulose are strong, flexible, and lightweight

The use of fossil fuels, such as the gasoline we put in our cars, emits large amounts of carbon dioxide into the atmosphere. Styrofoam, which is commonly used in packing and shipping, is made from fossil fuels. This means that the more we use styrofoam, the more carbon dioxide is being emitted into the atmosphere.

However, plants can take carbon dioxide out of the atmosphere and store it in the soil or in the plant itself. Plant matter has been used by humans in many ways, such as wood for a house or to make paper. Therefore, plant matter can be a good replacement for styrofoam and to take carbon out of the air. Plant matter is mainly made up of , hemicellulose, and lignin. Cellulose makes up 30-50% of a plant and it’s what gives a plant its structure. It is lightweight but has a high strength to weight ratio, making it strong and durable. It also has high tensile strength, meaning under tension or stretching, it will not break. These properties make cellulose a good structural material. Also, unlike styrofoam, cellulose is biodegradable and can be broken down by bacteria, fungi, and other decomposers.

Scientists have been researching more ways to use cellulose. They have found that cellulose can be broken down into very small components, called nanocrystals. Nanocrystals are separated from cellulose to isolate the strongest and most useful part of the cellulose. This means that nanocrystals have other properties that are not found in cellulose. For example, nanocrystals are strong and have low thermal conductivity. Nanocrystals could be used to make biofoam, which could replace materials such as styrofoam made from fossil fuels.

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Cellulose can be isolated from plants.

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References

“The hierarchical structure of a tree may be described as follows, from the macroscale to the nanoscale (Figure 1): a whole tree can be up to 100 m, the cross section contains structures on the centimeter scale, growth rings are measured in millimeters, the cellular anatomy is tens of micrometers, the configuration of hemicelluloses and lignin in the cellulose microfibrils measure tens of nanometers, and the molecular structure of cellulose is nanometric.

Cellulose fibrils are structural entities formed through a cellular manufacturing process, cellulose biogenesis, stabilized by hydrogen bonds and van der Waals forces. The fibrils contain crystalline and amorphous regions, with the latter being preferably degraded to release nanoscale components from the cellulose source by mechanical, chemical, or a combination of mechanical, chemical, and enzymatic processes…

Intermolecular hydrogen bonding creates fibrillar structures and semicrystalline packing, which governs the physical properties of cellulose: namely its high strength and flexibility.”

“Nanocellulose, which is either isolated from plant matter or biochemically produced in a lab, holds many of the desirable properties for which cellulose is known, including low density, nontoxicity, and high biodegradability. But it also holds unique properties, such as high mechanical strength, reinforcing capabilities, and tunable self-assembly in aqueous media, arising from its unique shape, size, surface chemistry, and high degree of crystallinity.”

Journal article

Nanocellulose, a versatile green platform: From biosources to materials and their applications.

Chemical Reviews | 07/11/2018 | Bejoy Thomas, Midhun C. Raj, Athira K. B, Rubiyah M. H, Jithin Joy, Audrey Moores,∥ Glenna L. Drisko, and Clément Sanchez

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Reference

“Environmentally friendly, sustainable, and high-performance thermal insulators are in high demand. Petroleum- based insulator foams usually have high thermal conductivity and pose health hazards. Here, we report ultralight composite foams that are highly strong, elastic, and super-insulating. The foams are composed of nanocrystalline cellulose (NCC) (74 wt%), polyvinyl alcohol (7.5 wt%), and a crosslinking agent (18.5 wt%).”

Journal article

Strong ultralight foams based on nanocrystalline cellulose for high-performance insulation.

Carbohydrate Polymers | 25/04/2019 | Peipei Wanga, Nahal Aliheidarib, Xiao Zhanga, Amir Ameli

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Reference

“In each region, the cell wall has three major components: cellulose microfibrils (with characteristic distributions and organiza- tion), hemicelluloses, and a matrix or encrusting material, typically pectin in primary walls and lignin in secondary walls (Panshin and deZeeuw 1980). In a general sense, cel- lulose can be understood as a long string-like molecule with high tensile strength; microfibrils are collections of cellulose molecules into even longer, stronger thread-like macromole- cules. Lignin is a brittle matrix material. The hemicelluloses are smaller, branched molecules thought to help link the lignin and cellulose into a unified whole in each layer of the cell wall.”

Book section

Chapter 3: Structure and Function of Wood.

Forest Products Laboratory | Alex Wiedenhoeft

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