Effective thermal insulation with wood foam

March 10, 2014 by Simone Peist
This wood foamed board is an entirely natural product made from sustainable raw materials. Credit: Fraunhofer WKI

Insulation materials of tomorrow must be both efficient and environmentally friendly. Fraunhofer scientists are developing insulation foam made from wood that could re- place petrochemical plastics in the long term.

Climate protection is now a mandatory consideration for every building contractor. Only last October the German federal government tightened up its Energy Saving Ordinance (EnEV) even further by decreeing that in future properties will have to consume even less energy than before. The key to meeting these stringent requirements lies in the way we insulate our walls and roofs, as effective insulation prevents large amounts of our valuable thermal energy escaping unused. Buildings are insulated by lining their facades with that reduce the transfer of heat to the outside environment. Traditionally the construction industry uses hardboards or expandable foams based on petrochemical plastics because they are good insulators that are affordable and easy to produce. But these materials are not particularly kind to the environment, so the long-term objective is to replace petroleum based products with materials derived from renewable resources.

Researchers at the Fraunhofer Institute for Wood Research, Wilhelm-Klauditz-Institut, WKI in Braunschweig have adopted a very promising approach to the problem by developing a method for creating from particles. "Our wood foam can be used in exactly the same way as conventional plastic spray foams, but is an entirely natural product made from sustainable raw materials," explains Professor Volker Thole of the WKI. The scientists produce the foam by grinding wood very finely until the tiny wood particles become a slimy mass. They then add gas to this suspension to expand it into a frothy foam that is then hardened. The hardening process is aided by natural substances contained in the wood itself. In an alternative method, specific chemical processes are used to produce the final product. "It's a bit like baking, when the dough rises and becomes firm in the oven," Professor Thole explains. Wood foam is a lightweight base material that can then be made into rigid foam boards and flexible foam mats.

Insulates as well as conventional plastic foams

Wood-based insulation materials are nothing new, but the products that are currently available have drawbacks. For instance, mats made from wood fibers and wood wool tend to shed fibers as they fibrillate and are less stable in shape than insulation materials made of plastic. "Over time, the currently used insulation mats made of wood fibers tend to sink in the middle due to temperature fluctuations and damp. This to some extend adversely affects its insulating properties," says Professor Thole. The wood foam developed at the WKI, however, is every bit as good as conventional plastic foams in this regard. "We analyzed our foam products in accordance with the applicable standards for insulation materials. Results were very promising; our products scored highly in terms of their thermo-insulating and mechanical properties as well as their hygric, or moisture-related, characteristics," Professor Thole reveals.

The Braunschweig-based scientists are currently experimenting with different types of wood to discover which tree species make the best basis for their product. Furthermore, they are working out suitable processes for mass-producing wood foams on an industrial scale. This innovative material could also be used in areas other than insulation, such as packaging. Packing materials made from wood foam would provide a long-term alternative to yet another oil-based product: expanded polystyrene.

Explore further: Composites, foams, and coatings—innovative plastics at the international K Trade Fair

Related Stories

Non-harmful flame retardants with no additional cost

July 23, 2013

Flame retardants are often extremely harmful to health. Despite this, they are found in many types of synthetic materials which would otherwise ignite quickly. Empa researchers have now succeeded in producing non-harmful ...

Uncovering liquid foam's bubbly acoustics

October 17, 2013

Liquid foams fascinate toddlers singing in a bubble bath. Physicists, too, have an interest in their acoustical properties. Borrowing from both porous material and foam science, Juliette Pierre from the Paris Diderot University, ...

Future solar cells may be made of wood

January 23, 2014

(Phys.org) —A new kind of paper that is made of wood fibers yet is 96% transparent could be a revolutionary material for next-generation solar cells. Coming from plants, the paper is inexpensive and more environmentally ...

Levitating foam liquid under the spell of magnetic fields

November 11, 2013

Foams fascinate, partly due to their short lifespan. Foams change as fluid drains out of their structure over time. It is precisely their ephemeral nature which has, until now, prevented scientists from experimentally probing ...

Recommended for you

Artificial photosynthesis gets big boost from new catalyst

November 20, 2017

A new catalyst created by U of T Engineering researchers brings them one step closer to artificial photosynthesis—a system that, just like plants, would use renewable energy to convert carbon dioxide (CO2) into stored chemical ...

Scientific advances can make it easier to recycle plastics

November 17, 2017

Most of the 150 million tons of plastics produced around the world every year end up in landfills, the oceans and elsewhere. Less than 9 percent of plastics are recycled in the United States, rising to about 30 percent in ...

The spliceosome—now available in high definition

November 17, 2017

UCLA researchers have solved the high-resolution structure of a massive cellular machine, the spliceosome, filling the last major gap in our understanding of the RNA splicing process that was previously unclear.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.