Kevlar (para-aramid) is a heat-resistant and strong 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.
Nylon is a generic designation for a family of synthetic polymers composed of polyamides. Nylon is a silk-like thermoplastic, generally made from petroleum, that can be melt-processed into fibers, films, or shapes. Nylon polymers can be mixed with a wide variety of additives to achieve many different property variations. Nylon polymers have found significant commercial applications in fabric and fibers, in shapes, and in films.
An electrolyte is a medium containing ions that is electrically conducting through the movement of ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon dissolving, the substance separates into cations and anions, which disperse uniformly throughout the solvent. Solid-state electrolytes also exist. In medicine and sometimes in chemistry, the term electrolyte refers to the substance that is dissolved.
Petrochemicals are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as maize, palm fruit or sugar cane.
Surfactants are compounds that lower the surface tension between two liquids, between a gas and a liquid, or between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, or dispersants. The word "surfactant" is a blend of surface-active agent, coined c. 1950.
A polyamide is a polymer with repeating units linked by amide bonds.
Twaron is a para-aramid. It is a heat-resistant and strong synthetic fibre developed in the early 1970s by the Dutch company Akzo Nobel's division Enka BV, later Akzo Industrial Fibers. The research name of the para-aramid fibre was originally Fiber X, but it was soon called Arenka. Although the Dutch para-aramid fiber was developed only a little later than DuPont's Kevlar, the introduction of Twaron as a commercial product came much later than Kevlar due to financial problems at the AKZO company in the 1970s.
In organic chemistry, an acyl chloride (or acid chloride) is an organic compound with the functional group -COCl. Their formula is usually written RCOCl, where R is a side chain. They are reactive derivatives of carboxylic acids. A specific example of an acyl chloride is acetyl chloride, CH3COCl. Acyl chlorides are the most important subset of acyl halides.
Polymer chemistry is a sub-discipline of chemistry that focuses on the chemical synthesis, structure, and chemical and physical properties of polymers and macromolecules. The principles and methods used within polymer chemistry are also applicable through a wide range of other chemistry sub-disciplines like organic chemistry, analytical chemistry, and physical chemistry. Many materials have polymeric structures, from fully inorganic metals and ceramics to DNA and other biological molecules, however, polymer chemistry is typically referred to in the context of synthetic, organic compositions. Synthetic polymers are ubiquitous in commercial materials and products in everyday use, commonly referred to as plastics, and rubbers, and are major components of composite materials. Polymer chemistry can also be included in the broader fields of polymer science or even nanotechnology, both of which can be described as encompassing polymer physics and polymer engineering.
Stephanie Louise Kwolek was a Polish-American chemist who is known for inventing Kevlar. Her career at the DuPont company spanned more than 40 years. She discovered the first of a family of synthetic fibers of exceptional strength and stiffness: poly-paraphenylene terephthalamide.
In polymer chemistry, a copolymer is a polymer derived from more than one species of monomer. The polymerization of monomers into copolymers is called copolymerization. Copolymers obtained by copolymerization of two monomer species are sometimes called bipolymers. Those obtained from three and four monomers are called terpolymers and quaterpolymers, respectively.
Microencapsulation is a process in which tiny particles or droplets are surrounded by a coating to give small capsules, with useful properties. In general, it is used to incorporate food ingredients, enzymes, cells or other materials on a micro metric scale. Microencapsulation can also be used to enclose solids, liquids, or gases inside a micrometric wall made of hard or soft soluble film, in order to reduce dosing frequency and prevent the degradation of pharmaceuticals.
Adipoyl chloride (or adipoyl dichloride) is the organic compound with the formula (CH2CH2C(O)Cl)2. It is a colorless liquid. It reacts with water to give adipic acid.
The ionic strength of a solution is a measure of the concentration of ions in that solution. Ionic compounds, when dissolved in water, dissociate into ions. The total electrolyte concentration in solution will affect important properties such as the dissociation constant or the solubility of different salts. One of the main characteristics of a solution with dissolved ions is the ionic strength. Ionic strength can be molar or molal and to avoid confusion the units should be stated explicitly. The concept of ionic strength was first introduced by Lewis and Randall in 1921 while describing the activity coefficients of strong electrolytes.
Radiation chemistry is a subdivision of nuclear chemistry which is the study of the chemical effects of radiation on matter; this is very different from radiochemistry as no radioactivity needs to be present in the material which is being chemically changed by the radiation. An example is the conversion of water into hydrogen gas and hydrogen peroxide.
Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include naturally occurring chemicals, such as in plants and insects, as well as synthetics such as polybutyrate. Natural polyesters and a few synthetic ones are biodegradable, but most synthetic polyesters are not. Synthetic polyesters are used extensively in clothing.
Sebacoyl chloride (or sebacoyl dichloride) is a di-acyl chloride, with formula (CH2)8(COCl)2. A colorless oily liquid with a pungent odor, it is soluble in hydrocarbons and ethers. Sebacoyl chloride is corrosive; like all acyl chlorides, it hydrolyzes, evolving hydrogen chloride. It is less susceptible to hydrolysis though than shorter chain aliphatic acyl chlorides.
Interfacial polymerization is a type of step-growth polymerization in which polymerization occurs at the interface between two immiscible phases, resulting in a polymer that is constrained to the interface. There are several variations of interfacial polymerization, which result in several types of polymer topologies, such as ultra-thin films, nanocapsules, and nanofibers, to name just a few.
Cardo polymers are a sub group of polymers where carbons in the backbone of the polymer chain are also incorporated into ring structures. These backbone carbons are quaternary centers. As such, the cyclic side group lies perpendicular to the plane of the polymer chain, creating a looping structure. These rings are bulky structures which sterically hinder the polymers and prevent them from packing tightly. They also restrict the rotational range of motion of the polymer chain, creating a rigid backbone. As a result of their unique structures, these polymers have notably high thermal stability and solubility. There have been recent advances made in the applications of cardo polymers to membranes used for gas separation and transport.
Tetramethylurea is the organic compound with the formula (Me2N)2CO. It is a substituted urea. This colorless liquid is used as an aprotic-polar solvent, especially for aromatic compounds and is used e. g. for Grignard reagents.
