aldehyde condensation polymer
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What is an aldehyde in chemistry?
An aldehyde is an organic compound distinguished by a carbon atom sharing a double bond with an oxygen atom, a single bond with a hydrogen atom, and a single bond with another atom or group of atoms. The double bond between carbon and oxygen is known as the carbonyl group.
Aldehydes are highly reactive and undergo various chemical reactions, including polymerization. When combined with other molecules, they form aldehyde condensation polymers, utilized in plastics like Bakelite. In almost all cases for the creation of these polymers, the aldehyde employed is formaldehyde, which is commonly polymerized with phenol, urea, or melamine to produce synthetic resins. These reactions release water and other by-products.
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What is a polymer?
A polymer consists of very large molecules, or macromolecules, that are multiples of simpler chemical units called monomers. An aldehyde condensation polymer is any polymeric substance produced through condensation reactions involving an aldehyde. These reactions generally involve formaldehyde reacting with phenol, urea, or melamine to create synthetic resins, releasing water and other by-products. The resulting polymers are widely used as adhesives in structural wood products and were formerly used to make plastics such as Bakelite.
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What does 'condensation' mean in chemistry?
In chemistry, a condensation reaction involves two molecules combining, typically with a catalyst, and eliminating a small molecule such as water. When this occurs between two identical molecules, it is called self-condensation.
In the context of aldehyde condensation polymers, an aldehyde, most often formaldehyde, polymerizes with phenol, urea, or melamine to create synthetic resins. These reactions are called condensation reactions because they produce water and other by-products. The resulting polymers are useful as adhesives in wood products.
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How can aldehydes be used to make polymers?
Aldehydes, a class of organic compounds characterized by a carbonyl group (C=O), can undergo a variety of chemical reactions, including polymerization. These polymerizations result in aldehyde condensation polymers, which are industrially produced polymeric substances built through condensation reactions involving an aldehyde.
In almost all cases, the specific aldehyde employed is formaldehyde, a highly reactive gas that is commonly polymerized with phenol, urea, or melamine to produce a series of important synthetic resins. The formation of the (CH_2) linkages generally follows a two-step process. In the first step, formaldehyde is reacted with one of the other monomers to produce a low-molecular-weight prepolymer consisting of small molecules in which a limited number of repeating units are linked together by methylol, or hydroxymethyl, groups ((CH_2OH)). In the second step, the prepolymer is cured (usually under heat and pressure and in the presence of a catalyst), and the (CH_2OH) groups are “condensed” to (CH_2) with the loss of water.
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What is an example of an aldehyde condensation polymer?
Aldehyde condensation polymers are any of a number of industrially produced polymeric substances that are built up in condensation reactions involving an aldehyde. These polymers are produced by the reaction of formaldehyde with phenol, urea, or melamine. The reaction is usually accompanied by the release of water and other by-products.
An example of an aldehyde condensation polymer is phenol-formaldehyde resin. Also known as phenolic resins, phenol-formaldehyde polymers were the first completely synthetic polymers to be commercialized.
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What are some uses of aldehyde condensation polymers in everyday life?
Aldehyde condensation polymers are industrially produced polymeric substances made through condensation reactions involving an aldehyde. These polymers are widely used as adhesives in structural wood products like plywood and particleboard.
Melamine-formaldehyde resin, a type of aldehyde condensation polymer, is known for its strength, hardness, and resistance to moisture and chemicals. It is used in products such as:
* Laminated countertops and tabletops
* Dishwasher-safe tableware
* Automotive surface coatingsPhenol-formaldehyde polymers are also molded into heat-resistant objects like appliance handles and electrical connectors.
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aldehyde condensation polymer, any of a number of industrially produced polymeric substances (substances composed of extremely large molecules) that are built up in condensation reactions involving an aldehyde. In almost all cases the particular aldehyde employed is formaldehyde, a highly reactive gas that is commonly polymerized with phenol, urea, or melamine to produce a series of important synthetic resins. The reactions by which these compounds are built up into polymers are referred to as condensation reactions because they are usually accompanied by the release of water and other by-products. The resultant polymers—known as phenol-formaldehyde resin, urea-formaldehyde resin, and melamine-formaldehyde resin—are widely used as adhesives in plywood and other structural wood products. In the first half of the 20th century they were made into very important plastics such as Bakelite and Beetleware.
Phenol, urea, melamine, and formaldehyde have the following molecular structures: 
Aldehydes are chemical compounds containing a carbonyl group (C=O), a highly reactive arrangement in which a carbon atom and an oxygen atom are joined by a double bond. Formaldehyde (chemical formula HCHO) is structurally the simplest member of this family. Produced by the oxidation of methane, it is a colourless, pungent-smelling gas that is commonly stored and handled in a liquid solution. Phenol (C6H5OH) is a phenyl alcohol consisting of a hydroxyl group (OH) appended to a six-sided, ring-shaped phenyl group (C6H5). Derived from cumene, which in turn is produced by a reaction between benzene and propylene, phenol is a toxic liquid that must be stored and handled under clearly established safety procedures.
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Urea (also called carbamide) and melamine (also called cyanuramide) are both colourless, crystalline solids containing an amino group (NH2). At one time both compounds were obtained from calcium cyanamide (and ultimately from calcium carbide). Urea is now produced by reacting carbon dioxide with ammonia, and melamine is obtained by the dehydration of urea.
These compounds are referred to as monomers, a general term for a class of compounds, mostly organic, that can link together in the presence of a catalyst to produce polymers. The aldehyde condensation polymers have the following general structures: 
In all three polymers the methylene groups (CH2) connected to the repeating units (and linking them to other units to produce giant molecules) are provided by the formaldehyde. The formation of the CH2 linkages generally follows a two-step process. In the first step, formaldehyde is reacted with one of the other monomers to produce a low-molecular-weight prepolymer consisting of small molecules in which a limited number of repeating units are linked together by methylol, or hydroxymethyl, groups (CH2OH). At this point the compound can be modified with fillers, pigments, and other additives and stored for future processing. In the second step, the prepolymer is cured (usually under heat and pressure and in the presence of a catalyst), and the CH2OH groups are “condensed” to CH2 with the loss of water. The polymers are thus thermoset, or interlinked into permanent three-dimensional networks that are ideally suited for the production of synthetic resins.