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Self Accelerating Decomposition Temperature
The self-accelerating decomposition temperature (SADT) is the lowest temperature at which an organic peroxide in a typical vessel or shipping package will undergo a self-accelerating decomposition within one week. The SADT is the point at which the heat evolution from the decomposition reaction and the heat removal rate from the package of interest become unbalanced. When the heat removal is too low, the temperature in the package increases and the rate of decomposition increases in an uncontrollable manner. The result is therefore dependent on the formulation and the package characteristics. A self-accelerating decomposition occurs when the rate of peroxide decomposition is sufficient to generate heat at a faster rate than it can be dissipated to the environment. Temperature is the main factor in determining the decomposition rate, although the size of the package is also important since its dimensions will determine the ability to dissipate heat to the environment. All peroxides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Peroxide
In organic chemistry, organic peroxides are organic compounds containing the peroxide functional group (). If the R′ is hydrogen, the compounds are called hydroperoxides, which are discussed in that article. The O−O bond of peroxides easily breaks, producing free radicals of the form (the dot represents an unpaired electron). Thus, organic peroxides are useful as radical initiator, initiators for some types of polymerization, such as the Acrylic resin, acrylic, unsaturated polyester, and vinyl ester resins used in glass-reinforced plastics. methyl ethyl ketone peroxide, MEKP and benzoyl peroxide are commonly used for this purpose. However, the same property also means that organic peroxides can explosively combust. Organic peroxides, like their inorganic counterparts, are often powerful bleaching agents. Types of organic peroxides Organic peroxides are classified (i) by the presence or absence of a hydroxyl () terminus and (ii) by the presence of alkyl vs acyl substituents. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Decomposition
Chemical decomposition, or chemical breakdown, is the process or effect of simplifying a single molecular entity, chemical entity (normal molecule, reaction intermediate, etc.) into two or more fragments. Chemical decomposition is usually regarded and defined as the exact opposite of chemical synthesis. In short, the chemical reaction in which two or more products are formed from a single reactant is called a decomposition reaction. The details of a decomposition process are not always well defined. Nevertheless, some activation energy is generally needed to break the involved bonds and as such, higher temperatures generally accelerates decomposition. The net reaction can be an endothermic process, or in the case of spontaneous decompositions, an exothermic process. The stability of a chemical compound is eventually limited when exposed to extreme environmental conditions such as heat, radiation, humidity, or the acidity of a solvent. Because of this chemical decomposition is often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peroxide
In chemistry, peroxides are a group of Chemical compound, compounds with the structure , where the R's represent a radical (a portion of a complete molecule; not necessarily a free radical) and O's are single oxygen atoms. Oxygen atoms are joined to each other and to adjacent elements through Single bond, single covalent bonds, denoted by dashes or lines. The group in a peroxide is often called the peroxide group, though some nomenclature discrepancies exist. This linkage is recognized as a common polyatomic ion, and exists in many molecules. General structure The characteristic structure of any regular peroxide is the oxygen–oxygen covalent single bond, which connects the two main atoms together. In the event that the molecule has no chemical Substituent, substituents, the peroxide group will have a [−2] Formal charge, net charge. Each oxygen atom has a charge of negative one, as 5 of its Valence electron, valence electrons remain in the outermost Atomic orbital, orbital ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homolysis (chemistry)
In chemistry, homolysis () or homolytic fission is the dissociation of a molecular bond by a process where each of the fragments (an atom or molecule) retains one of the originally bonded electrons. During homolytic fission of a neutral molecule with an even number of electrons, two Free-radical halogenation, radicals will be generated. That is, the two electrons involved in the original bond are distributed between the two fragment species. Bond cleavage is also possible by a process called Heterolysis (chemistry), heterolysis. The energy involved in this process is called bond dissociation energy (BDE). BDE is defined as the "enthalpy (per Mole (unit), mole) required to break a given bond of some specific molecular entity by homolysis," symbolized as ''D''. BDE is dependent on the Bond energy, strength of the bond, which is determined by factors relating to the stability of the resulting Radical (chemistry), radical species. Because of the relatively high energy required to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radical (chemistry)
In chemistry, a radical, also known as a free radical, is an atom, molecule, or ion that has at least one unpaired valence electron. With some exceptions, these unpaired electrons make radicals highly chemically reactive. Many radicals spontaneously dimerize. Most organic radicals have short lifetimes. A notable example of a radical is the hydroxyl radical (HO·), a molecule that has one unpaired electron on the oxygen atom. Two other examples are triplet oxygen and triplet carbene (꞉) which have two unpaired electrons. Radicals may be generated in a number of ways, but typical methods involve redox reactions. Ionizing radiation, heat, electrical discharges, and electrolysis are known to produce radicals. Radicals are intermediates in many chemical reactions, more so than is apparent from the balanced equations. Radicals are important in combustion, atmospheric chemistry, polymerization, plasma chemistry, biochemistry, and many other chemical processes. A majority ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maximum Safe Storage Temperature
The maximum safe storage temperature (MSST) is the highest temperature to store a chemical (like an organic peroxide) above which slow decomposition Decomposition is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and is ess ... and explosion may occur. References * Chemical safety {{explosive-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cross-link
In chemistry and biology, a cross-link is a bond or a short sequence of bonds that links one polymer chain to another. These links may take the form of covalent bonds or ionic bonds and the polymers can be either synthetic polymers or natural polymers (such as proteins). In polymer chemistry "cross-linking" usually refers to the use of cross-links to promote a change in the polymers' physical properties. When "crosslinking" is used in the biological field, it refers to the use of a probe to link proteins together to check for protein–protein interactions, as well as other creative cross-linking methodologies. Although the term is used to refer to the "linking of polymer chains" for both sciences, the extent of crosslinking and specificities of the crosslinking agents vary greatly. Synthetic polymers : 260px, left, Chemical reactions associated with crosslinking of drying oils, the process that produces curing'' refers to the crosslinking of thermosetting">linoleum. Cros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exothermic
In thermodynamics, an exothermic process () is a thermodynamic process or reaction that releases energy from the system to its surroundings, usually in the form of heat, but also in a form of light (e.g. a spark, flame, or flash), electricity (e.g. a battery), or sound (e.g. explosion heard when burning hydrogen). The term ''exothermic'' was first coined by 19th-century French chemist Marcellin Berthelot. The opposite of an exothermic process is an endothermic process, one that absorbs energy, usually in the form of heat. The concept is frequently applied in the physical sciences to chemical reactions where chemical bond energy is converted to thermal energy (heat). Two types of chemical reactions Exothermic and endothermic describe two types of chemical reactions or systems found in nature, as follows: Exothermic An exothermic reaction occurs when heat is released to the surroundings. According to the IUPAC, an exothermic reaction is "a reaction for which the overall stand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radical Polymerization
In polymer chemistry, radical polymerization (RP) is a method of polymerization by which a polymer forms by the successive addition of a radical to building blocks ( repeat units). Radicals can be formed by a number of different mechanisms, usually involving separate initiator molecules. Following its generation, the initiating radical adds (nonradical) monomer units, thereby growing the polymer chain. Radical polymerization is a key synthesis route for obtaining a wide variety of different polymers and materials composites. The relatively non-specific nature of radical chemical interactions makes this one of the most versatile forms of polymerization available and allows facile reactions of polymeric radical chain ends and other chemicals or substrates. In 2001, 40 billion of the 110 billion pounds of polymers produced in the United States were produced by radical polymerization. Radical polymerization is a type of chain polymerization, along with anionic, cationic and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Dioxide
Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at normally-encountered concentrations it is odorless. As the source of carbon in the carbon cycle, atmospheric is the primary carbon source for life on Earth. In the air, carbon dioxide is transparent to visible light but absorbs infrared, infrared radiation, acting as a greenhouse gas. Carbon dioxide is soluble in water and is found in groundwater, lakes, ice caps, and seawater. It is a trace gas Carbon dioxide in Earth's atmosphere, in Earth's atmosphere at 421 parts per million (ppm), or about 0.042% (as of May 2022) having risen from pre-industrial levels of 280 ppm or about 0.028%. Burning fossil fuels is the main cause of these increased concentrations, which are the primary cause of climate change.IPCC (2022Summary for pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methane
Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The abundance of methane on Earth makes it an economically attractive fuel, although capturing and storing it is difficult because it is a gas at standard temperature and pressure. In the Earth's atmosphere methane is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. Methane is an Organic chemistry, organic Organic compound, compound, and among the simplest of organic compounds. Methane is also a hydrocarbon. Naturally occurring methane is found both below ground and under the seafloor and is formed by both geological and biological processes. The largest reservoir of methane is under the seafloor in the form of methane clathrates. When methane reaches the surface and the Atmosphere of Earth, atmosphere, it is known as atmospheric methane. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
