By Robert F. Service Aug. 10, 2018 , sciencemag.org
Plastic-wood composites have long been a favorite of homeowners looking to build decks and fences that don’t require sanding, staining, and painting.

But these engineered woods typically aren’t as strong as natural wood and can be even more prone to catching fire. Now, researchers report they’ve created a synthetic wood (pictured) that matches natural wood’s strength and is flame resistant to boot.
One key to wood’s strength is a component called lignin, a natural polymer with a weblike structure that binds tiny crystallites of another component called cellulose together. The new composites replace lignin with a synthetic polymer version called resol, which has a similar weblike structure. Researchers used resol to bind a variety of different synthetic crystallites together into a family of different synthetic woods in which the color and other properties could be tailored by the crystallites added.
As the composites cure, they adopt a cell-like structure that looks like natural wood’s cellular structure. This helps the materials resist compression, lending them high strength. And because resol is fire retardant, the final composites don’t catch fire even when exposed to an open flame, the researchers report today in Science Advances.
And, unlike trees, which can take decades to grow, the new synthetic version takes shape in just hours.