Cellulose nanocrystals (CNC) obtained from wood by-products materials such as wood chips and sawdust can be used to produce affordable low cost ballistic armor.Prepared properly, CNCs are stronger and stiffer than Kevlar or carbon fibers, so that putting CNC into composite materials results in high strength, low weight products. In addition, the cost of CNCs is less than ten percent of the cost of Kevlar fiber or carbon fiber. These qualities have attracted the interest of the military for use in lightweight armor and ballistic glass (CNCs are transparent), as well as companies in the automotive, aerospace, electronics, consumer products, and medical industries.
Don’t be carried away by the looks of cellulose, common cellulose looks a little like wet tissue paper (not surprising, since paper is mostly cellulose), and isn’t especially strong. By processing cellulose further than has been the case to date, it’s possible to extract CNC fibrils with incredible tensile strength. Tensile strength and elasticity is measured in Pascals, and ballistic fiber most commonly in giga-Pascals (GPa). Kevlar 49 has an elasticity of 125 GPa and a tensile strength of 3.5GPa. CNC’s numbers are 150 GPa and 7.5 GPa, respectively.
The only reinforcing material that is stronger than cellulose nanocrystals is a carbon nanotube, which costs about 100 times as much.