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XLPE
Cross-linked polyethylene, commonly abbreviated PEX, XPE or XLPE, is a form of polyethylene with cross-links. It is used predominantly in building services pipework systems, hydronic radiant heating and cooling systems, domestic water piping, insulation for high tension (high voltage) electrical cables, and baby play mats. It is also used for natural gas and offshore oil applications, chemical transportation, and transportation of sewage and slurries. PEX is an alternative to polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC) or copper tubing for use as residential water pipes. Properties Low-temperature impact strength, abrasion resistance and environmental stress cracking resistance can be increased significantly by crosslinking, whereas hardness and rigidity are somewhat reduced. Compared to thermoplastic polyethylene, PEX does not melt (analogous to elastomers) and is thermally resistant (over longer periods of up to 120 °C, for short periods without e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
XLPE Powder In Mold Used In Rotational Molding By Roto Dynamics Inc
Cross-linked polyethylene, commonly abbreviated PEX, XPE or XLPE, is a form of polyethylene with cross-links. It is used predominantly in building services pipework systems, hydronic radiant heating and cooling systems, domestic water piping, insulation for high tension (high voltage) electrical cables, and baby play mats. It is also used for natural gas and offshore oil applications, chemical transportation, and transportation of sewage and slurries. PEX is an alternative to polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC) or copper tubing for use as residential water pipes. Properties Low-temperature impact strength, abrasion resistance and environmental stress cracking resistance can be increased significantly by crosslinking, whereas hardness and rigidity are somewhat reduced. Compared to thermoplastic polyethylene, PEX does not melt (analogous to elastomers) and is thermally resistant (over longer periods of up to 120 °C, for short periods without ele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-voltage Cable
A high-voltage cable (HV cable) is a cable used for electric power transmission at high voltage. A cable includes a conductor and insulation. Cables are considered to be fully insulated. This means that they have a fully rated insulation system that will consist of insulation, semi-con layers, and a metallic shield. This is in contrast to an overhead line, which may include insulation but not fully rated for operating voltage (EG: tree wire). High-voltage cables of differing types have a variety of applications in instruments, ignition systems, and alternating current (AC) and direct current (DC) power transmission. In all applications, the insulation of the cable must not deteriorate due to the high-voltage stress, ozone produced by electric discharges in air, or tracking. The cable system must prevent contact of the high-voltage conductor with other objects or persons, and must contain and control leakage current. Cable joints and terminals must be designed to control the hig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyethylene
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging (plastic bags, plastic films, geomembranes and containers including bottles, etc.). , over 100 million tonnes of polyethylene resins are being produced annually, accounting for 34% of the total plastics market. Many kinds of polyethylene are known, with most having the chemical formula (C2H4)''n''. PE is usually a mixture of similar polymers of ethylene, with various values of ''n''. It can be ''low-density'' or ''high-density'': low-density polyethylene is extruded using high pressure () and high temperature (), while high-density polyethylene is extruded using low pressure () and low temperature (). Polyethylene is usually thermoplastic, but it can be modified to become thermosetting instead, for example, in cross-linked polyethylene. History Polyethylene was first synthesized by the German ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalyst
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usually gaseous or liquid) as the reactant, or heterogeneous, whose components are not in the same phase. Enzymes and other biocatalysts are often considered as a third category. Catalysis is ubiquitous in chemical industry of all kinds. Estimates are that 90% of all commercially produced chemical products involve catalysts at some sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrolysis
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis is the cleavage of biomolecules where a water molecule is consumed to effect the separation of a larger molecule into component parts. When a carbohydrate is broken into its component sugar molecules by hydrolysis (e.g., sucrose being broken down into glucose and fructose), this is recognized as saccharification. Hydrolysis reactions can be the reverse of a condensation reaction in which two molecules join into a larger one and eject a water molecule. Thus hydrolysis adds water to break down, whereas condensation builds up by removing water. Types Usually hydrolysis is a chemical process in which a molecule of water is added to a substance. Sometimes this addition causes both the substance and water molecule to split into two parts. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laboratory Water Bath
A water bath is laboratory equipment made from a container filled with heated water. It is used to incubate samples in water at a constant temperature over a long period of time. Most water baths have a digital or an analogue interface to allow users to set a desired temperature, but some water baths have their temperature controlled by a current passing through a reader. Utilisations include warming of reagents, melting of substrates or incubation of cell cultures. It is also used to enable certain chemical reactions to occur at high temperature. Water baths are preferred heat sources for heating flammable chemicals, as their lack of open flame prevents ignition. Different types of water baths are used depending on application. For all water baths, it can be used up to 99.9 °C. When temperature is above 100 °C, alternative methods such as oil bath, silicone bath or sand bath may be used. Precautions * Use with caution. * It is not recommended to use water bat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Functionality (chemistry)
In chemistry, functionality is the presence of functional groups in a molecule. A monofunctional molecule possesses one functional group, a difunctional two, a trifunctional three, and so forth. In organic chemistry (and other fields of chemistry), a molecule's functionality has a decisive influence on its reactivity. In polymer chemistry, the functionality of a monomer refers to its number of polymerizable groups, and affects the formation and the degree of crosslinking of polymers. Functionality in organic chemistry and material science In organic chemistry, functionality is often used as a synonym for functional group. For example, a hydroxyl group can also be called a HO-function. ''Functionalisation'' means the introduction of functional groups, for example * the functionalisation of a surface (e.g. silanization for the specific modification of the adhesion of a surface) * the functionalization of nanoparticles of a metal or metal oxide to stabilize such nanopa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silanes
Silanes refers to diverse kinds of charge-neutral silicon compounds with the formula . The R substituents can any combination of organic or inorganic groups. Most silanes contain Si-C bonds, and are discussed under organosilicon compounds. Examples: *Silane , the parent. * Binary silicon-hydrogen compounds (which are sometimes called silanes also) includes silane itself but also compounds with Si-Si bonds including disilane and longer chains. *Silanes with one, two, three, or four Si-H bonds are called hydrosilanes. Silane itself is the parent member. Examples: triethylsilane () and triethoxysilane (). *Polysilanes are organosilicon compounds with the formula . They include all binary silicon-hydrogen compounds except the parent, although these tend to be less useful because they are fragile. Attracting more interest, are the organic derivatives such as polydimethylsilane and dodecamethylcyclohexasilane * Chlorosilanes have Si-Cl bonds. Examples: trichlorosilane () and tetr ... [...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 electron, unpaired valence electron. With some exceptions, these unpaired electrons make radicals highly chemical reaction, chemically reactive. Many radicals spontaneously dimer (chemistry), 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 methylene radical, 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 (ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crosslinking PE Scheme En , a parasurgical treatment for corneal ectasia and keratoconus
{{Disambiguation ...
Cross-linking may refer to *Cross-link, a chemical bond of one polymer chain to another *Corneal collagen cross-linking Corneal cross-linking (CXL) with riboflavin (vitamin B2) and UV-A light is a surgical treatment for corneal ectasia such as keratoconus, PMD, and post-LASIK ectasia. It is used in an attempt to make the cornea stronger. According to a 2015 Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
