Kevlar (para-aramid) is a strong, heat-resistant synthetic fiber, related to other aramids such as Nomex and Technora. Developed by Stephanie Kwolek at DuPont in 1965, the high-strength material was first used commercially in the early 1970s as a replacement for steel in racing tires. It is typically spun into ropes or fabric sheets that can be used as such, or as an ingredient in composite material components.
Fiber is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate fibers, for example carbon fiber and ultra-high-molecular-weight polyethylene.
Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. This process differs from absorption, in which a fluid is dissolved by or permeates a liquid or solid. While adsorption does often precede absorption, which involves the transfer of the absorbate into the volume of the absorbent material, alternatively, adsorption is distinctly a surface phenomenon, wherein the adsorbate does not penetrate through the material surface and into the bulk of the adsorbent. The term sorption encompasses both adsorption and absorption, and desorption is the reverse of sorption.
Aramid fibers, short for aromatic polyamide, are a class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications, for ballistic-rated body armor fabric and ballistic composites, in marine cordage, marine hull reinforcement, as an asbestos substitute, and in various lightweight consumer items ranging from phone cases to tennis rackets.
Activated carbon, also called activated charcoal, is a form of carbon commonly used to filter contaminants from water and air, among many other uses. It is processed (activated) to have small, low-volume pores that greatly increase the surface area available for adsorption or chemical reactions that can be thought of as a microscopic "sponge" structure. Activation is analogous to making popcorn from dried corn kernels: popcorn is light, fluffy, and its kernels have a high surface-area-to-volume ratio. Activated is sometimes replaced by active.
Amyloids are aggregates of proteins characterised by a fibrillar morphology of typically 7–13 nm in diameter, a β-sheet secondary structure and ability to be stained by particular dyes, such as Congo red. In the human body, amyloids have been linked to the development of various diseases. Pathogenic amyloids form when previously healthy proteins lose their normal structure and physiological functions (misfolding) and form fibrous deposits within and around cells. These protein misfolding and deposition processes disrupt the healthy function of tissues and organs.
Pressure swing adsorption (PSA) is a technique used to separate some gas species from a mixture of gases under pressure according to the species' molecular characteristics and affinity for an adsorbent material. It operates at near-ambient temperature and significantly differs from the cryogenic distillation commonly used to separate gases. Selective adsorbent materials are used as trapping material, preferentially adsorbing the target gas species at high pressure. The process then swings to low pressure to desorb the adsorbed gas.
Adsorption refrigeration was invented by Michael Faraday in 1821, even though the basis of artificial modern refrigeration dates back to 1748 with William Cullen's experiments. Adsorption is sometimes referred to as solid sorption.
Supercritical carbon dioxide is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure.
Filament winding is a fabrication technique mainly used for manufacturing open (cylinders) or closed end structures. This process involves winding filaments under tension over a rotating mandrel. The mandrel rotates around the spindle while a delivery eye on a carriage traverses horizontally in line with the axis of the rotating mandrel, laying down fibers in the desired pattern or angle to the rotational axis. The most common filaments are glass or carbon and are impregnated with resin by passing through a bath as they are wound onto the mandrel. Once the mandrel is completely covered to the desired thickness, the resin is cured. Depending on the resin system and its cure characteristics, often the mandrel is autoclaved or heated in an oven or rotated under radiant heaters until the part is cured. Once the resin has cured, the mandrel is removed or extracted, leaving the hollow final product. For some products such as gas bottles, the 'mandrel' is a permanent part of the finished product forming a liner to prevent gas leakage or as a barrier to protect the composite from the fluid to be stored.
Carbon filtering is a method of filtering that uses a bed of activated carbon to remove impurities from a fluid using adsorption.
Carbon nanotubes (CNTs) are cylinders of one or more layers of graphene (lattice). Diameters of single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) are typically 0.8 to 2 nm and 5 to 20 nm, respectively, although MWNT diameters can exceed 100 nm. CNT lengths range from less than 100 nm to 0.5 m.
Capacitive deionization (CDI) is a technology to deionize water by applying an electrical potential difference over two electrodes, which are often made of porous carbon. In other words, CDI is an electro-sorption method using a combination of a sorption media and an electrical field to separate ions and charged particles. Anions, ions with a negative charge, are removed from the water and are stored in the positively polarized electrode. Likewise, cations are stored in the cathode, which is the negatively polarized electrode.
The electrochemical regeneration of activated carbon based adsorbents involves the removal of molecules adsorbed onto the surface of the adsorbent with the use of an electric current in an electrochemical cell restoring the carbon's adsorptive capacity. Electrochemical regeneration represents an alternative to thermal regeneration commonly used in waste water treatment applications. Common adsorbents include powdered activated carbon (PAC), granular activated carbon (GAC) and activated carbon fibre.
Electrochemical regeneration of activated carbon adsorbents such as granular activated carbon present an alternative to thermal regeneration or land filling at the end of useful adsorbent life. Continuous adsorption-electrochemical regeneration encompasses the adsorption and regeneration steps, typically separated in the bulk of industrial processes due to long adsorption equilibrium times, into one continuous system. This is possible using a non-porous, electrically conducting carbon derivative called Nyex. The non-porosity of Nyex allows it to achieve its full adsorptive capacity within a few minutes and its electrical conductivity allows it to form part of the electrode in an electrochemical cell. As a result of its properties Nyex can undergo quick adsorption and fast electrochemical regeneration in a combined adsorption-electrochemical regeneration cell achieving 100% regeneration efficiency.
Nanocellulose is a term referring to a family of cellulosic materials that have at least one of their dimensions in the nanoscale. Examples of nanocellulosic materials are microfibrilated cellulose, cellulose nanofibers or cellulose nanocrystals. Nanocellulose may be obtained from natural cellulose fibers through a variety of production processes. This family of materials possesses interesting properties suitable for a wide range of potential applications.
Setralit is a technical natural fiber based on plant fibers whose property profile has been modified selectively in order to meet different industrial requirements. It was first manufactured in 1989 by Jean-Léon Spehner, an Alsatian engineer, and further developed by the German company ECCO Gleittechnik GmbH. The name “Setralit“ is derived from the French company Setral S.à.r.l. which is a subsidiary company of ECCO, where Spehner was employed at that time. Setralit was officially described first in 1990.
Aerogels are a class of synthetic porous ultralight material derived from a gel, in which the liquid component for the gel has been replaced with a gas, without significant collapse of the gel structure. The result is a solid with extremely low density and extremely low thermal conductivity. Aerogels can be made from a variety of chemical compounds. Silica aerogels feel like fragile styrofoam to the touch, while some polymer-based aerogels feel like rigid foams.
Nanosized aluminium oxide occurs in the form of spherical or nearly spherical nanoparticles, and in the form of oriented or undirected fibers.
The Curli protein is a type of amyloid fiber produced by certain strains of enterobacteria. They are extracellular fibers located on bacteria such as E. coli and Salmonella spp. These fibers serve to promote cell community behavior through biofilm formation in the extracellular matrix. Amyloids are associated with several human neurodegenerative diseases such as Alzheimer's disease, Huntington's disease, Parkinson's disease, and prion diseases. The study of curli may help to understand human diseases thought to arise from improper amyloid fiber formation. The curli pili are generally assembled through the extracellular nucleation precipitation pathway.
