Polyols contain reactive hydroxyl OH groups which react with isocyanate NCO groups on isocyanates to form polyurethane adhesives.
Polyether-based polyurethane adhesives exhibit enhanced hydrolytic stability and excellent resistance to weak acids and bases compared to polyester-based polyurethane adhesives.
However, polyether-based polyurethane adhesives are more susceptible to UV radiation and provide poor resistance to oils and fuels compared to polyester-based polyurethane adhesives. Polyether polyols are formed by propoxylating an initiator addition of propylene oxide to an initiator.
In some cases, the initiator is ethoxylated addition of ethylene oxide as well as propoxylated. Ethoxylation can be incorporated in the middle of the polyol, or at the end tip of the polyol. When polyether polyols have ethylene oxide tips, the resulting hydroxyl groups are primary hydroxyls; propylene oxide tips yield secondary hydroxyl groups.
Secondary hydroxyl groups react slower than primary hydroxyl groups as a result of the increased steric hindrance. Ethylene oxide is more hydrophilic, and thus polyether polyols with ethylene content tend to produce polyurethane adhesives that are more hydrophilic than those produced with polyether polyols that are made solely with propylene oxide.
The initiator used to produce the polyol can impact reactivity as well as functionality of the polyol. Amine initiated polyether polyols are self-catalyzing and react faster than standard glycol initiated polyether polyols.
Sucrose initiated polyols allow for the manufacture of polyols with greater than 7 hydroxyl groups compared to triols formed by trimethylolpropane.
There are several key characteristics which define what performance properties a given high functionality polyether polyol will impart in a given polyurethane adhesive. Hydroxyl number OH is the measure of the hydroxyl group content of gram of polyol.
Lower hydroxyl values indicates lower hydroxyl content and a higher molecular weight for the overall polyol. Increasing the number of OH groups results in greater crosslinking. Greater crosslinking yields stiffer, harder products with enhanced chemical and thermal resistance.
Polyols that contain 2 hydroxyl groups are called diols, polyols with 3 functional groups are called triols, polyol groups with 4 hydroxyl groups are called tetrols. Click here to request a quote. Chemicals Ltd.
Polyether ether ketone
Chemicals Limited Shepard Bros. Ideas Inc.For the best experience, please use one of the latest browsers. There are two main types of polyurethane: polyester and polyether.
Polyester urethane and polyether urethane are elastomers, meaning that they possess elastic properties, and both offer unique performance properties. There are two types of abrasion resistance sliding and impingement.
Sliding refers to scraping and rubbing abrasion while impingement refers to particles or objects striking the urethane surface at a high angle. All elastomers rubbers, urethanes, silicones, etc. Both polyesters and polyethers can be made to any hardness from marshmallow-soft to bowling ball hard. Products such as skate wheels need to return the energy they absorb when your foot pushes them into the pavement rebound ; otherwise, you would feel like you are running in soft sand.
Sand absorbs most of the energy from your foot and makes you run sluggishly. If the product will come in contact with oils, fuel or solvents even vapors your choice should be a. Go to Navigation Go to Content.
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That is why they are the choice for high-speed rollers where the rapid flexing creates heat. Polyether is less affected by cold temperatures.
Sometimes you want the product to absorb the energy it receives opposite of rebound. Ask Our Experts. Phone number.The polymeric materials known as polyurethanes form a family of polymers which are essentially different from most other plastics in that there is no urethane monomer and the polymer is almost invariably created during the manufacture of a particular object.
Polyurethanes are made by the exothermic reactions between alcohols with two or more reactive hydroxyl -OH groups per molecule diols, triols, polyols and isocyanates that have more than one reactive isocyanate group -NCO per molecule diisocyanates, polyisocyanates. For example a diisocyanate reacts with a diol:. The group formed by the reaction between the two molecules is known as the 'urethane linkage'. It is the essential part of the polyurethane molecule. The physical properties, as well as the chemical structure, of a polyurethane depend on the structure of the original reactants, in particular the R 1 and the R 2 groups.
The characteristics of the polyols - relative molecular mass, the number of reactive functional groups per molecule, and the molecular structure - influence the properties of the final polymer, and hence how it is used.
There is a fundamental difference between the manufacture of most polyurethanes and the manufacture of many other plastics. Polymers such as poly ethene and poly propene are produced in chemical plants and sold as granules, powders or films. Products are subsequently made from them by heating the polymer, shaping it under pressure and cooling it. The properties of such end-products are almost completely dependent on those of the original polymer.
Polyurethanes, on the other hand are usually made directly into the final product. Much of the polyurethanes produced are in the form of large blocks of foam, which are cut up for use in cushions, or for thermal insulation. The chemical reaction can also take place in moulds, leading to, for example, a car bumper, a computer casing or a building panel. It may occur as the liquid reactants are sprayed onto a building surface or coated on a fabric.
The combined effects of controlling the polymer properties and the density lead to the existence of a very wide range of different materials so that polyurethanes are used in very many applications Table 1. Polyurethanes can be rigid or rubbery at any density between, say 10 kg m -3 and kg m The overall range of properties available to the designer and the manufacturer is clearly very wide and this is reflected in the many, very different, uses to which polyurethanes are put.
In Expected to be Research and Markets, Plastics - the Facts PlasticsEurope, As polyurethanes are made from the reaction between an isocyanate and a polyol, the section is divided into three parts: a production of isocyanates b production of polyols c production of polyurethanes.
Although many aromatic and aliphatic polyisocyanates exist, two are of particular industrial importance. They are:. TDI was developed first but is now used mainly in the production of low density flexible foams for cushions.
The starting material is methylbenzene toluene. When it reacts with mixed acid nitric and sulfurictwo isomers of nitromethylbenzene NMB are the main products.
If this mixture is nitrated further, a mixture of dinitromethylbenzenes is produced. In industry they are known by their trivial names, 2,4-dinitrotoluene and 2,6-dinitrotoluene DNT.
In turn, the amines, known commercially as Toluene Diamines or TDA, are heated with carbonyl chloride phosgene to produce the diisocyanates and this process can be carried out in the liquid phase with chlorobenzene as a solvent at about K:.
Alternatively, these reactions are carried out in the gas phase by vaporizing the diamines at ca K and mixing them with carbonyl chloride. This is an environmental and economic improvement over the liquid phase process as no solvent is needed.PEEK polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts. Typical is the reaction of 4,4'-difluorobenzophenone with the disodium salt of hydroquinonewhich is generated in situ by deprotonation with sodium carbonate.
PEEK is a semicrystalline thermoplastic with excellent mechanical and chemical resistance properties that are retained to high temperatures. The processing conditions used to mold PEEK can influence the crystallinity and hence the mechanical properties. Its Young's modulus is 3. The thermal conductivity increases nearly linearly with temperature between room temperature and solidus temperature. It is soluble in concentrated sulfuric acid at room temperature, although dissolution can take a very long time unless the polymer is in a form with a high surface-area-to-volume ratio, such as a fine powder or thin film.
It has high resistance to biodegradation. Because of its robustness, PEEK is used to fabricate items used in demanding applications, including bearingspiston parts, pumpsHigh-performance liquid chromatography columns, compressor plate valvesand electrical cable insulation. It is one of the few plastics compatible with ultra-high vacuum applications. PEEK is considered an advanced biomaterial used in medical implantse. PEEK is finding increased use in spinal fusion devices and reinforcing rods.
It is extensively used in the aerospace, automotive, and chemical process industries. In the range of its melting temperature it can be processed using injection moulding or extrusion methods. It is technically feasible to process granular PEEK into filament form and 3D printing parts from the filament material using fused deposition modeling — FDM or fused filament fabrication — FFF technology.
In its solid state PEEK is readily machinable, for example, by CNC milling machines and is commonly used to produce high-quality plastic parts that are thermostable and both electrically and thermally insulating.
PEEK is considered a high-performance polymerthat is to say, its high price restricts its use to the most demanding applications only. PEEK is not traditionally a shape-memory polymer ; however, recent advances in processing have allowed shape-memory behavior in PEEK with mechanical activation. This technology has expanded to applications in orthopedic surgery. From Wikipedia, the free encyclopedia. Retrieved 23 April Polymers, High-Temperature. Ullmann's Encyclopedia of Industrial Chemistry online Version.
Blumm, A. Lindemann, A. Richard; McCabe, Richard W. Polymer Degradation and Stability.
Crain Communications Inc. Retrieved May 6, Solvay Press Releases. LouVan Communications Inc. Retrieved 27 January Design News. Thermoplastic Thermosetting polymer Duroplast Corrugated plastic Polymeric foam High performance plastics.Polyetherany of a class of organic substances prepared by joining together or polymerizing many molecules of simpler compounds monomers by establishing ether links between them; polyethers, which may be either chainlike or networklike in molecular structure, comprise an unusually diverse group of polymers.
Polyethylene glycols are water-soluble liquids or waxy solids used in cosmetic and pharmaceutical preparations and in the manufacture of emulsifying or wetting agents and lubricants. Polypropylene glycols are liquids, mostly insoluble in water, used to suppress foaming in industrial processes and for making polyurethane resins, hydraulic fluids, and various other materials. Epoxy resinswidely used as coatings and adhesives, are prepared by converting liquid polyethers into infusible solids by connecting the long-chain molecules into networks, a process called curing.
Phenoxy resins are polyethers similar to those used in epoxies, but the polymers are of higher molecular weight and do not require curing; they are used mostly as metal primers. Penton, a chlorine-containing polyether unaffected by many chemicals, is fabricated into sheets used for lining storage tanks and the like. Info Print Cite. Submit Feedback.
Thank you for your feedback. Polyether chemical compound. See Article History. Read More on This Topic. Polyether s are polymers that are formed by the joining of monomers through ether linkages—i.
Learn More in these related Britannica articles:. Polyether s are polymers that are formed by the joining of monomers through ether linkages— i. A variety of polyethers are manufactured, ranging from engineering plastics to elastomers. The compounds also differ markedly in structure, though they all…. History at your fingertips. Sign up here to see what happened On This Dayevery day in your inbox!
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More About.A polyol is an organic compound containing multiple hydroxyl groups. The term "polyol" can have a slightly different meaning in food science and polymer chemistry. A molecule with more than two hydroxyl groups is a polyol, with three — a triol, and with four — a tetrol.
By convention, polyols do not refer to compounds that contain other functional groups. Sugar alcoholsa class of polyols, are commonly obtained by hydrogenation of sugars. Sugar alcohols are added to foods because of their lower caloric content than sugars ; however, they are also, in general, less sweet, and are often combined with high-intensity sweeteners. They are also added to chewing gum because they are not broken down by bacteria in the mouth or metabolized to acids, and thus do not contribute to tooth decay.
Maltitolsorbitolxylitolerythritoland isomalt are common sugar alcohols. The term polyol is used for a number of polyethers of polyols and polyesters "polyether polyols" and "polyester polyols". Polyols are used, inter alia, as a monomer in combination with diisocyanates in the production of polyurethanes. The term "polyol" is also attributed to polymers comprising a multitude of hydroxyl groups, e.
Cellulose is a polymer with many alcohol groups, but it is usually not referred to as a polyol. A distinction has to be made between polymeric compounds containing terminal hydroxyl groups polyether polyols and polyester polyols and polymeric compounds containing multiple hydroxyl groups e. Polymeric polyols react with isocyanates to make polyurethaneswhich find use to make mattressesfoam insulation for refrigerators and freezershome and automotive seats, elastomeric shoe soles, fibers e.
Spandexand adhesives. Low molecular weight polyols are widely used in polymer chemistrywhere they function as crosslinking agents. Alkyd resins for example are used in paints and in moulds for casting. They are the dominant resin or "binder" in most commercial "oil-based" coatings. Approximatelytons of alkyd resins are produced each year.
They are based on linking reactive monomers with through ester formation. Polyols used in the production of commercial alkyd resins are glycerol, trimethylolpropane, and pentaerythritol.
The preparation of metal nanoparticles often employ the "polyol method. Such diols serve as both reductants and surface-protecting agents for the nanoparticles. Since the generic term polyol is only derived from chemical nomenclature and just indicates the presence of several hydroxyl groups, no common properties can be assigned to all polyols. However, polyols are usually highly viscous when polymeric to solid when low-molecular weight at room temperature. This is due to the fact that hydrogen bonds are formed between the individual molecules.
From Wikipedia, the free encyclopedia. Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. Angewandte Chemie International Edition. CS1 maint: uses authors parameter link. Categories : Polyols Sugar substitutes Organic polymers Commodity chemicals.
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Applicable to the surrounding of doors and windows indoor decoration and stru. DOPUN is one component oil-soluble polyurethane grouting material it reac. DT is a one component polyurethane coating with isocyanate polyether poly. DJD blend polyols is the environmental friendly product in polyurethane i.
Polyester Vs Polyether
SD is polyether polyol based on propylene glycol BHT free. Used for elast. TDI is belongs to isocyanate products which is widely used in producing polyu. This series product is mainly solid in normal temperature with molecular weig.
MDI is widely used in the production of PU rigid insulation foams and polyiso. This product is a mixture of high activity high molecular weight polyether po. This product is a type of blend polyols which is specially researched for rig. Water based Flexible PU foam is an environmental protection type using water.
DN - blend polyether polyol for high flame retardant B1Classexterior wal. DQTB is high density spray blend polyols it reacts with isocyanate to pro. DBCB blend polyols is a compound which consists of polyether polyols surf.
DBCA uses special polyether polyols as the main raw materials with specia.Polyol And Isocyanate reaction
Used special polyol as main raw materials with special additives to make up o. This product uses special polyol as main raw material with special additives. Rigid Blended Polyols Series. Wood Imitation Series. Home Appliances Series. Water Heaters Series. Energy Saving Construction. Special Polyether Polyol. Water-Proof Series. Pu Water-Proof Coating. Water Stoppage Material.
Used for elastomer chain extender polyurethane grouting material This series product is mainly solid in normal temperature with molecular weight molecular weight can be adjusted as c