"Super wood" that is harder than steel can make cars and planes

[Chinese Packaging Network News] Wood is harder than steel? According to the February 25 report from the American media, scientists at the University of Maryland developed a new super material called "super wood" that is harder, lighter, and cheaper than steel.

The report said that Hu Liangbin and Li Teng, Ph.D., of the University of Maryland, have been looking for new ways to use wood. Previously, they had made wood cells, transparent wood that was harder than glass, and used wood burning water. This time, they successfully developed "Super Wood."

Hu Liangbin said: "We are interested in replacing the steel and carbon fibers with strong wood structures." After testing with inexpensive and expensive wood, respectively, the research team found that the results were very similar. He said that the strength and toughness of wood treated by experiments were 11.5 times and 10 times higher than those of natural wood, respectively.

The research report was published on the website of Nature magazine on February 7. According to the report, wood samples were first boiled under a mixed aqueous solution of sodium hydroxide and sodium sulfite, and then the cell walls of the treated wood were pressed by hot pressing to form regularly arranged cellulose nanofibers. The resulting fully densified wood is much stronger than natural wood and will become a competitor to steel and even titanium alloys, as well as carbon fiber - at a much cheaper price.

The method is divided into two steps, first removing some of the lignin in the wood and then compressing it at a temperature of 100 degrees Celsius. The thickness of wood can be reduced by 80% while the density is increased by 2 times. The mechanical properties such as toughness, rigidity, hardness, and impact resistance are over 10 times that of the original wood.

Tensile strength refers to the maximum stress a material can withstand before it is broken. Super Wood's tensile strength can reach 587 MPa, which is comparable to steel. Specific tensile strength refers to the tensile strength divided by the density. This indicator is important for applications in areas such as automobiles and aerospace that are sensitive to weight. Due to the low density of wood, Super Wood's tensile strength exceeds almost all metal and alloy materials, even titanium alloys. Tests have shown that a high-speed injection of small steel columns cannot penetrate laminates laminated by 5-layer super wood.

He also said that a key part of "super wood" is the removal of a chemical called lignin. "Lignon is like a binder in all natural elements of natural wood. In our experiments, we discovered that to completely increase the density of wood, you have to remove some of the binder."

Hu Liangbin and Li Teng said that after removing half of the lignin by applying chemical substances and applying pressure to wood for about one day, the strength and lightness of the wood is sufficient for the purpose of building automobiles, airplanes, wind turbines and more. They even said that sawmills may one day replace steel mills.

The researchers pointed out that Super Wood has the potential to replace metals and other materials in the fields of architecture, transportation, and aerospace. Academician Gao Huajian, an academician of the American Academy of Engineering and a professor at Brown University, commented that this research provides a great potential for designing lightweight, high-performance structural materials, and in engineering applications that require high strength, high toughness, and high impact resistance. Wide application prospects. “Excitingly, they are able to handle the raw wood easily and apply it to all types of wood.”

Imagine that if the technology is to be industrialized and applied in large scale in the future, it will completely change the development of the structural materials industry. It will not only turn raw materials from non-renewable iron ore and other mineral resources into renewable wood resources, but also prices. Lower and more environmentally friendly.

Demand for wood will also increase by an order of magnitude. How many shares of plantation forest will be used for pulp production? Where will prices go?