MFC is normally produced from highly purified wood fiber (WF) and plant fiber (PF) pulps by high pressure homogenization according to the procedures developed at ITT Rayonnier.6263 Pulp is produced by using a mixture of sodium hydroxide and sodium sulfide and thus so-called Kraft pulp (almost pure cellulose fibers) is obtained. Pulping with salts of sulfurous acid leads to cellulose named sulphite pulp (which contains more by-products in the cellulose fibers). MFC particles are con­sidered to comprise of several elementary fibrils. Each one of them consisting of 36 cellulose chains has a high aspect ratio or ~10-100 nm wide and 0.5-10 pm in length. MFCs are ~100% cellulose, and contain both amorphous and crystalline regions. In food and cosmetic industries, MFCs have been used as a thickening agent.64