Nanocellulose Is No Small Thing

Trees could become part of electronics, medical devices, and military gear

For centuries, the forestry industry has produced paper and lumber. But what if trees could be transformed into an entirely new set of products, ranging from electronic sensors to biomedical implants to military protective gear?

The idea isn’t as improbable as it sounds. Researchers are studying a nanoscale material that can be extracted from trees and, in some forms, is about as strong as Kevlar. Called “nanocellulose,” this lightweight material is composed of bundled sugar chains from the cell walls of wood. Researchers can extract nanocellulose by grinding pulp or using chemicals to break it down into tiny particles. At such small scales, the material has fewer defects, making it stronger. One type of nanocellulose particle, called cellulose nanocrystals, is especially tough because the sugar chains are arranged in a highly ordered structure.

Researchers envision a huge array of applications for nanocellulose. It could partially replace fossil fuel–based products such as petroleum-derived plastics and might be cheaper than other high-performance nanoscale materials. Clear sheets of nanocellulose might be useful for windows or electronic displays. Studies have shown that some forms of cellulose are piezoelectric, meaning they generate an electrical signal when deformed, so nanocellulose-based sensors could potentially monitor structures such as bridges for signs of stress. Nanocellulose food packaging could block oxygen permeation and keep the contents from spoiling, while nanocellulose scaffolds implanted in the body might aid bone regeneration. And at the U.S. Army Research Laboratory in Maryland, researchers are investigating whether nanocellulose-reinforced materials could better protect soldiers on the battlefield.

One of the more feasible applications is paper. By adding nanocellulose to paper and reducing the amount of other ingredients such as pulp, companies might be able to create lighter, stronger sheets. Since this paper would require less material and thus less energy to make, it could have a lower carbon footprint, says Phil Jones, director of new ventures and disruptive technologies at the industrial minerals company Imerys in Roswell, Georgia, which is investigating the use of nanocellulose in paper.

“It is a sustainable, renewable, biodegradable, biocompatible nanomaterial,” says Richard Berry, chief technology officer of CelluForce, a joint venture of the Canadian pulp and paper company Domtar Corporation and the nonprofit forest research institute FPInnovations. Nanocellulose is the first nanomaterial that combines all those properties, he says.

Scientists have known about nanocellulose for decades. But by using new microscopy and measurement tools, researchers can now study this material in detail. With electronic devices eating into paper sales and the housing crash cutting the demand for building materials, the forestry industry is searching for ways to expand its markets.

“The markets are drying up,” says Theodore Wegner, assistant director of the U.S. Forest Service’s Forest Products Laboratory in Madison, Wisconsin. Wegner worries that if private forest owners can’t make enough money sustainably managing their forests and selling wood, they will sell the land to developers.

Companies and research institutions have already begun establishing plants to produce nanocellulose. CelluForce opened a demonstration plant in Windsor, Quebec, in January and aims to make 1,000 kilograms per day. The U.S. Forest Service, which has started providing samples to researchers, is setting up a small-scale nanocellulose facility in Madison. And scientists at the University of Maine in Orono plan to open a pilot plant by the end of the year.

It’s unclear whether companies can produce enough nanocellulose at low enough cost to be successful—or, after energy use for production has been tallied, whether the material will be truly green. But optimistic researchers predict that nanocellulose-based products could hit the market within a few years. “These are the materials of the twenty-first century,” says Jones. ❧

—Roberta Kwok

Photo ©Innventia