Microfibrillated

Microfibrillated describes materials that have been processed to form microfibrils, very slender fibers with diameters typically in the tens to hundreds of nanometers and lengths ranging from micrometers to several micrometers. The term is most commonly associated with microfibrillated cellulose (MFC), produced from wood or other plant fibers, but can also apply to other polymeric systems that are fibrillated to micro-scale dimensions.

Production methods involve mechanical disintegration of fibers through refining, high-pressure homogenization, microfluidization, grinding, or combinations of these. Pretreatments such as enzymatic hydrolysis, TEMPO-mediated oxidation, or acid treatments may be used to promote fibrillation and to tailor surface chemistry for better dispersion in matrices.

Key properties of microfibrillated materials include a high surface area, a high aspect ratio, and the ability to form three-dimensional networks. When dispersed in a matrix, they can enhance mechanical strength, modify rheology, and improve barrier properties. The materials are typically renewable and biodegradable and may exhibit moisture sensitivity depending on processing and storage conditions.

Applications span reinforcing fillers in paper, paperboard, and biocomposites; thickening and rheology-modifying agents in coatings, paints, and cosmetics; and barrier films for packaging. They are also explored as components in nanocomposites, bio-based films, and additive manufacturing, including some 3D printing formulations.

Terminology often centers on microfibrillated cellulose as the best-known example, with related terms such as nanofibrillated cellulose and cellulose nanofibrils reflecting variations in dimension and processing.