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Carbomer
Poly(acrylic acid) (PAA; trade name Carbomer) is a polymer with the formula (CH2−CHCO2H)''n''. It is a derivative of acrylic acid (CH2=CHCO2H). In addition to the homopolymers, a variety of copolymers and crosslinked polymers, and partially deprotonated derivatives thereof, are known and of commercial value. In a water solution at neutral pH, PAA is an anionic polymer, i.e., many of the side chains of PAA lose their protons and acquire a negative charge. Partially or wholly deprotonated PAAs are polyelectrolytes, with the ability to absorb and retain water and swell to many times their original volume. These properties acid–base and water-attracting are the basis of many applications. Synthesis PAA, like any acrylate polymer, is usually synthesized through a process known as free radical polymerization, though graft polymerization may also be used. Free radical polymerization involves the conversion of monomers, in this case, acrylic acid (CH2=CHCO2H), into a polymer chain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymer
A polymer () is a chemical substance, substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeat unit, repeating subunits derived from one or more species of monomers. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass, relative to small molecule compound (chemistry), compounds, produces unique physical property, physical properties including toughness, high rubber elasticity, elasticity, viscoelasticity, and a tendency to form Amorphous solid, amorphous and crystallization of polymers, semicrystalline structures rath ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interpolymer Complexes
Interpolymer complexes (IPC) are the products of non-covalent interactions between complementary unlike macromolecules in solutions. There are four types of these complexes: * Interpolyelectrolyte complexes (IPEC) or polyelectrolyte complexes (PEC) * Hydrogen-bonded interpolymer complexes * Stereocomplexes * Charge-transfer complexes Formation of interpolymer complexes Interpolymer complexes can be prepared either by mixing complementary polymers in solutions or by matrix (template) polymerisation. It is also possible to prepare IPCs at liquid-liquid interfaces or at solid or soft surfaces. Usually the structure of IPCs formed will depend on many factors, including the nature of interacting polymers, concentrations of their solutions, nature of solvent and presence of inorganic ions or organic molecules in solutions. Mixing of dilute polymer solutions usually leads to formation of IPCs as a colloidal dispersion, whereas more concentrated polymer solutions form IPCs in the form of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quenching
In materials science, quenching is the rapid cooling of a workpiece in water, gas, oil, polymer, air, or other fluids to obtain certain material properties. A type of heat treating, quenching prevents undesired low-temperature processes, such as phase transformations, from occurring. It does this by reducing the window of time during which these undesired reactions are both thermodynamically favorable and kinetically accessible; for instance, quenching can reduce the crystal grain size of both metallic and plastic materials, increasing their hardness. In metallurgy, quenching is most commonly used to harden steel by inducing a martensite transformation, where the steel must be rapidly cooled through its eutectoid point, the temperature at which austenite becomes unstable. Rapid cooling prevents the formation of cementite structure, instead forcibly dissolving carbon atoms in the ferrite lattice. In steel alloyed with metals such as nickel and manganese, the eutectoid t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrylate Polymer
An acrylate polymer (also known as acrylic or polyacrylate) is any of a group of polymers prepared from acrylate monomers. These plastics are noted for their transparency, resistance to breakage, and elasticity. Acrylate polymer is commonly used in cosmetics, such as nail polish, as an adhesive. History The first synthesis of acrylic polymer was reported by G. W. A. Kahlbaum in 1880. Acrylic elastomers Acrylic elastomer is a general term for a type of synthetic rubber whose primary component is acrylic acid alkylester ( ethyl or butyl ester). Acrylic elastomer possesses characteristics of heat and oil resistance, with the ability to withstand temperatures of 170–180 °C. It is used primarily for producing oil seals and packaging related to automobiles. Acrylic elastomer can generally be characterized as one of two types. "Old" types include ACM ( copolymer of acrylic acid ester and 2-chloroethyl vinyl ether) containing chlorine and ANM (copolymer of acrylic acid e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkali
In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The adjective alkaline, and less often, alkalescent, is commonly used in English as a synonym for basic, especially for bases soluble in water. This broad use of the term is likely to have come about because alkalis were the first bases known to obey the Arrhenius definition of a base, and they are still among the most common bases. Etymology The word ''alkali'' is derived from Arabic ''al qalīy'' (or ''alkali''), meaning (see calcination), referring to the original source of alkaline substances. A water-extract of burned plant ashes, called potash and composed mostly of potassium carbonate, was mildly basic. After heating this substance with calcium hydroxide (''slaked lime''), a far more strongly basic substance known as ''caustic potash ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flocculation
In colloidal chemistry, flocculation is a process by which colloidal particles come out of Suspension (chemistry), suspension to sediment in the form of floc or flake, either spontaneously or due to the addition of a clarifying agent. The action differs from Precipitation (chemistry), precipitation in that, prior to flocculation, colloids are merely suspended, under the form of a stable dispersion (where the internal phase (solid) is dispersed throughout the external phase (fluid) through mechanical agitation) and are not truly dissolved in Solution (chemistry), solution. Coagulation (water treatment), Coagulation and flocculation are important processes in fermentation and water treatment with coagulation aimed to destabilize and aggregate particles through chemical interactions between the coagulant and colloids, and flocculation to sediment the destabilized particles by causing their aggregation into floc. Term definition According to the IUPAC definition, flocculation is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkali Metal
The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K),The symbols Na and K for sodium and potassium are derived from their Latin names, ''natrium'' and ''kalium''; these are still the origins of the names for the elements in some languages, such as German and Russian. rubidium (Rb), caesium (Cs), and francium (Fr). Together with hydrogen they constitute Group (periodic table)#Group names, group 1, which lies in the s-block of the periodic table. All alkali metals have their outermost electron in an s-orbital: this shared electron configuration results in their having very similar characteristic properties. Indeed, the alkali metals provide the best example of periodic trends, group trends in properties in the periodic table, with elements exhibiting well-characterised Homologous series, homologous behaviour. This family of elements is also known as the lithium family after its leading element. The alkali metals are all shiny, hardness, sof ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmetics
Cosmetics are substances that are intended for application to the body for cleansing, beautifying, promoting attractiveness, or altering appearance. They are mixtures of chemical compounds derived from either Natural product, natural sources or created synthetically. Cosmetics have various purposes, including personal care, personal and skin care. They can also be used to conceal blemishes and enhance natural features (such as the eyebrows and eyelashes). Makeup can also add colour to a person's face, enhance a person's features or change the appearance of the face entirely to resemble a different person, creature, or object. People have used cosmetics for thousands of years for skin care and appearance enhancement. Visible cosmetics for both women and men have gone in and out of fashion over the centuries. Some early forms of cosmetics contained harmful ingredients such as lead that caused serious health problems and sometimes resulted in death. Modern commercial cosmetic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paint
Paint is a material or mixture that, when applied to a solid material and allowed to dry, adds a film-like layer. As art, this is used to create an image or images known as a painting. Paint can be made in many colors and types. Most paints are either oil-based or water-based, and each has distinct characteristics. Primitive forms of paint were used tens of thousands of years ago in cave paintings. Clean-up solvents are also different for water-based paint than oil-based paint. Water-based paints and oil-based paints will cure differently based on the outside ambient temperature of the object being painted (such as a house). History Paint was used in some of the earliest known human artworks. Some cave paintings drawn with red or yellow ochre, hematite, manganese oxide, and charcoal may have been made by early ''Homo sapiens'' as long as 40,000 years ago. Paint may be even older. In 2003 and 2004, South African archeologists reported finds in Blombos Cave of a 100,000-y ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorhexidine Gluconate
Chlorhexidine is a disinfectant and antiseptic which is used for skin disinfection before surgery and to disinfect surgical instruments. It is also used for cleaning wounds, preventing dental plaque, treating yeast infections of the mouth, and to keep urinary catheters from blocking. It is used as a liquid or a powder. It is commonly used in salt form, either the gluconate or the acetate. Side effects may include skin irritation, tooth discoloration, and allergic reactions, although, apart from discoloration, the risk appears to be the same as that for povidone-iodine. Chlorhexidine rinse is also known to have a bitter metallic aftertaste. Rinsing with water is not recommended as it is known to increase the bitterness. It may cause eye problems if direct contact occurs. Use in pregnancy appears to be safe. Chlorhexidine may come mixed in alcohol, water, or surfactant solution. It is effective against a range of microorganisms, but does not inactivate spores. Chlorhe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiseptic
An antiseptic ( and ) is an antimicrobial substance or compound that is applied to living tissue to reduce the possibility of sepsis, infection, or putrefaction. Antiseptics are generally distinguished from ''antibiotics'' by the latter's ability to safely destroy bacteria within the body, and from ''disinfectants'', which destroy microorganisms found on non-living objects. Antibacterials include antiseptics that have the proven ability to act against bacteria. Microbicides which destroy virus particles are called viricides or antivirals. Antifungals, also known as antimycotics, are pharmaceutical fungicides used to treat and prevent mycosis (fungal infection). Surgery Antiseptic practices evolved in the 19th century through multiple individuals. Ignaz Semmelweis showed already in 1847-1848 that hand washing prior to delivery reduced puerperal fever. Despite this, many hospitals continued to practice surgery in unsanitary conditions, with some surgeons taking pride in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disposable Diapers
A diaper (, North American English) or a nappy (British English, Australian English, Hiberno-English) is a type of underwear that allows the wearer to urinate or defecate without using a toilet, by absorbing or containing waste products to prevent soiling of outer clothing or the external environment. When diapers become wet or soiled, they require changing, generally by a second person such as a parent or caregiver. Failure to change a diaper on a sufficiently regular basis can result in skin problems around the area covered by the diaper. Diapers are made of cloth or synthetic disposable materials. Cloth diapers are composed of layers of fabric such as cotton, hemp, bamboo, microfiber, or even plastic fibers such as PLA or PU, and can be washed and reused multiple times. Disposable diapers contain absorbent chemicals and are thrown away after use. Diapers are primarily worn by infants, toddlers who are not yet toilet trained, and by children who experience bedwetting. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
