Texarkana, TX 78° View Live Radar Thu H 75° L 57° Fri H 79° L 62° Sat H 80° L 63° Weather Sponsored By:

'Nanowood': Invention could reduce humanity's carbon footprint

'Nanowood': Invention could reduce humanity's carbon footprint

March 13th, 2018 by Los Angeles Times in Features

Tian Li, left, and Liangbing Hu hold pieces of nanowood, a strong, lightweight material that serves as an effective insulator. (Hua Xie/University of Maryland)

Scientists have designed a heat-insulating material made from wood that is both light and strong and made entirely from tiny, stripped-down wood fibers.

The so-called nanowood, described in the journal Science Advances, could one day be used to make more energy-efficient buildings. It's cheap and biodegradable, too.

"Nature is producing this kind of material," said senior author Liangbing Hu, a materials scientist and engineer at the University of Maryland in College Park.

Managing heat is a major issue in the cities we build. It's hard to keep heat indoors in the winter and keep it outdoors in the summer. The insulating materials currently in use are often very expensive to make, both in terms of money and of energy. They're not usually biodegradable and ultimately contribute to our growing landfills. So scientists have been trying to come up with cheaper, more environmentally friendly options.

Hu has been probing the properties of nanocellulose, nanometer-scale versions of cellulose, the tough carbohydrate in the cell walls of plants that allows tree trunks to grow strong and tall. At these incredibly small scales, cellulose fibers can take on remarkable characteristics, including a strength-to-weight ratio that's about eight times that of steel.

Hu and his team have already developed a strong, dense material they called super wood, in part by removing some of the wood's lignin—a complex polymer that holds cellulose in the wood together, almost like glue—and hemicellulose, another component of woody tissue.

But for this project, Hu and his colleagues removed all of the lignin and most of the hemicellulose. Lignin is very good at conducting heat—which means it would be a terrible insulator. Without all that lignin, the woody material turned pure white, allowing it to reflect incoming light rather than absorb it (which also helps to block heat).

The secret to nanowood's insulating powers lies partly in its structure. Styrofoam is isotropic: It basically looks the same from any angle. But nanowood is anisotropic: The fibers are bundled together in parallel, so it looks very different from different angles. Heat can travel up and down the fibers with ease, but can't easily cross them, particularly because of the air gaps left after all the woody filler (lignin and hemicellulose) was removed.

The scientists found that the nanowood was just as good an insulator as Styrofoam—slightly better, even. It far outclassed other materials, too.

On top of that, the nanowood was also lightweight and could withstand pressures of 13 megapascals. That's about 50 times higher than insulators like cellulose foam and more than 30 times higher than the strongest of the commercially-used thermal insulation materials, they said.

"To the best of our knowledge, the strength of our nanowood represents the highest value among available super insulating materials," the study authors wrote.

Even better, nanocellulose is readily available and relatively cheap to process, potentially costing as little as $7.44 per square meter. (The key to keeping it sustainable, Hu added, would be to harvest fast-growing trees like balsa, and leave slow-growing trees alone.) In the right conditions, bacteria can eat it, making it biodegradable.

"When the thickness is less than 1 mm, the nanowood slice can be rolled and folded, making it suitable for scenarios that require flexibility, such as pipelines in chemical factories and power plants," the authors wrote.

Hu said that such a strong, lightweight, thermally insulating biodegradable material could have a host of future uses. It could be used to build skyscrapers, to manufacture cars, even protect heat-sensitive electronics, whether on Earth or in space.

Getting Started/Comments Policy

Getting started

  1. 1. If you frequently comment on news websites then you may already have a Disqus account. If so, click the "Login" button at the top right of the comment widget and choose whether you'd rather log in with Facebook, Twitter, Google, or a Disqus account.
  2. 2. If you've forgotten your password, Disqus will email you a link that will allow you to create a new one. Easy!
  3. 3. If you're not a member yet, Disqus will go ahead and register you. It's seamless and takes about 10 seconds.
  4. 4. To register, either go through the login process or just click in the box that says "join the discussion," type your comment, and either choose a social media platform to log you in or create a Disqus account with your email address.
  5. 5. If you use Twitter, Facebook or Google to log in, you will need to stay logged into that platform in order to comment. If you create a Disqus account instead, you'll need to remember your Disqus password. Either way, you can change your display name if you'd rather not show off your real name.
  6. 6. Don't be a huge jerk or do anything illegal, and you'll be fine.

Texarkana Gazette Comments Policy

The Texarkana Gazette web sites include interactive areas in which users can express opinions and share ideas and information. We cannot and do not monitor all of the material submitted to the website. Additionally, we do not control, and are not responsible for, content submitted by users. By using the web sites, you may be exposed to content that you may find offensive, indecent, inaccurate, misleading, or otherwise objectionable. You agree that you must evaluate, and bear all risks associated with, the use of the Gazette web sites and any content on the Gazette web sites, including, but not limited to, whether you should rely on such content. Notwithstanding the foregoing, you acknowledge that we shall have the right (but not the obligation) to review any content that you have submitted to the Gazette, and to reject, delete, disable, or remove any content that we determine, in our sole discretion, (a) does not comply with the terms and conditions of this agreement; (b) might violate any law, infringe upon the rights of third parties, or subject us to liability for any reason; or (c) might adversely affect our public image, reputation or goodwill. Moreover, we reserve the right to reject, delete, disable, or remove any content at any time, for the reasons set forth above, for any other reason, or for no reason. If you believe that any content on any of the Gazette web sites infringes upon any copyrights that you own, please contact us pursuant to the procedures outlined in the Digital Millennium Copyright Act (Title 17 U.S.C. § 512) at the following address:

Copyright Agent
The Texarkana Gazette
15 Pine Street
Texarkana, TX 75501
Phone: 903-794-3311
Email: webeditor@texarkanagazette.com