Milled and compressed wood is a material that is stronger than steel

bybenjgibbs

Steel is known as a very hard material, but there is a method published in science journal nature to create a material that is stronger than steel by "the process of pulverizing and compressing wood".

Crushed wood is stronger than steel
https://www.nature.com/articles/d41586-018-01600-6

Although research to raise the strength of wood has been done for many years, most of it has been included in the cell wall of plantscelluloseNatural rigid insidepolymer,Cellulose nanofibersWe focused on extracting new materials and creating new materials by combining them.

The research team of Mr. Li Teng of the University of Maryland said he tried to strengthen the timber from a different angle from the previous approach. The team put several woods such as oak wood in sodium hydroxide and sodium sulfite solution and boiled for 7 hours. As a result, starchy cellulose remained almost completely, but otherLigninThere was a lot of holes in the structure of the wood where the ingredient including the ingredient flowed out.

After that, the team compressed the wood for 1 day at a high temperature of 100 degrees. And the molded wood has a thickness of 1/5 of the original wood, the density has tripled and the strength has improved 11.5 times. Considering that the strength increase was about 3 to 4 times in the previous approach, this is a great achievement.

byjasmeet

When scanning the newly produced material with a scanning electron microscope, it seems that the crushed cellulose fibers are found to be intertwined with each other. Michaela Eder of Max Planck Institute in Germany said, "Although it has been known that strength can be obtained by compressing wood up to now, the influence that the entanglement of cellulose nanofibers contributes to strength has not been known "It is said.

The research team hit a steel bullet at 30 meters per second from an air gun used for durability testing of military vehicles in order to measure the strength of the material. Then, the 3 mm thick layer of five thin plates of new material succeeded to stop steel bullets. Although the speed of 30 meters per second is a speed slower than the actual shoot, it seems to be about the same speed as a vehicle accident, and it can be said that it is sufficient strength for use in ordinary vehicles.

byAlessio Michelini

However, other researchers said that some people say that "using other methods can make cheaper and stronger materials". Mr. Fred Kamquaw of Oregon State University says, "Compressing at higher temperature without removing wood lignin, finally coating with resin can produce almost the same material".

Mr. Feng co-researcher Fu Liang Bin said, "By removing moderate lignin it is possible to bring out the best strength of wood," removing 45% lignin from wood When it was done, it said that the material with the highest strength was obtained. We also know that too low lignin will result in low density and fragile material.

Mr. Eder talked about the results of the research presented by Mr. Ten and others, "I have found the possibility of research in this direction.The point of trying to increase strength by using properties unique to trees is wonderful. It is a material. "