A monomer (/ˈmɒnəmər/ MON-ə-mər; mono-, "one" + -mer, "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or three-dimensional network in a process called polymerization.
Monomer molecule: A molecule which can undergo polymerization, thereby contributing constitutional units to the essential structure of a macromolecule.
Classification
Chemistry classifies monomers by type, and two broad classes based on the type of polymer they form.
By type:
- natural vs synthetic, e.g. glycine vs caprolactam, respectively
- polar vs nonpolar, e.g. vinyl acetate vs ethylene, respectively
- cyclic vs linear, e.g. ethylene oxide vs ethylene glycol, respectively
By type of polymer they form:
- those that participate in condensation polymerization
- those that participate in addition polymerization
Differing stoichiometry causes each class to create its respective form of polymer.
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This nylon is formed by condensation polymerization of two monomers, yielding water
The polymerization of one kind of monomer gives a homopolymer. Many polymers are copolymers, meaning that they are derived from two different monomers. In the case of condensation polymerizations, the ratio of comonomers is usually 1:1. For example, the formation of many nylons requires equal amounts of a dicarboxylic acid and diamine. In the case of addition polymerizations, the comonomer content is often only a few percent. For example, small amounts of 1-octene monomer are copolymerized with ethylene to give specialized polyethylene.
Synthetic monomers
- Ethylene gas (H2C=CH2) is the monomer for polyethylene.
- Other modified ethylene derivatives include:
- tetrafluoroethylene (F2C=CF2) which leads to Teflon
- vinyl chloride (H2C=CHCl) which leads to PVC
- styrene (C6H5CH=CH2) which leads to polystyrene
- Epoxide monomers may be cross linked with themselves, or with the addition of a co-reactant, to form epoxy
- BPA is the monomer precursor for polycarbonate
- Terephthalic acid is a comonomer that, with ethylene glycol, forms polyethylene terephthalate.
- Dimethylsilicon dichloride is a monomer that, upon hydrolysis, gives polydimethylsiloxane.
- Ethyl methacrylate is an acrylic monomer that, when combined with an acrylic polymer, catalyzes and forms an acrylate plastic used to create artificial nail extensions
Biopolymers
The term "monomeric protein" may also be used to describe one of the proteins making up a multiprotein complex.
Natural monomers
Some of the main biopolymers are listed below:
Amino acids
For proteins, the monomers are amino acids. Polymerization occurs at ribosomes. Usually about 20 types of amino acid monomers are used to produce proteins. Hence proteins are not homopolymers.
Nucleotides
For polynucleic acids (DNA/RNA), the monomers are nucleotides, each of which is made of a pentose sugar, a nitrogenous base and a phosphate group. Nucleotide monomers are found in the cell nucleus. Four types of nucleotide monomers are precursors to DNA and four different nucleotide monomers are precursors to RNA.
Glucose and related sugars
For carbohydrates, the monomers are monosaccharides. The most abundant natural monomer is glucose, which is linked by glycosidic bonds into the polymers cellulose, starch, and glycogen.
Isoprene
Isoprene is a natural monomer that polymerizes to form a natural rubber, most often cis-1,4-polyisoprene, but also trans-1,4-polymer. Synthetic rubbers are often based on butadiene, which is structurally related to isoprene.
See also
- Protein subunit
- List of publications in polymer chemistry
- Prepolymer
Notes
- Young, R. J. (1987) Introduction to Polymers, Chapman & Hall ISBN 0-412-22170-5
- International Union of Pure and Applied Chemistry, et al. (2000) IUPAC Gold Book, Polymerization
- Clayden, Jonathan; Greeves, Nick; Warren, Stuart; Wothers, Peter (2001). Organic Chemistry (1st ed.). Oxford University Press. pp. 1450–1466. ISBN 978-0-19-850346-0.
- Jenkins, A. D.; Kratochvíl, P.; Stepto, R. F. T.; Suter, U. W. (1996). "Glossary of basic terms in polymer science (IUPAC Recommendations 1996)". Pure and Applied Chemistry. 68 (12): 2287–2311. doi:10.1351/pac199668122287.
- D. Margerison; G. C. East; J. E. Spice (1967). An Introduction to Polymer Chemistry. Pergamon Press. ISBN 978-0-08-011891-8.
- Bruce Alberts, Alexander Johnson, Julian Lewis, Otin Raff, Keith Roberts, and Peter Walter, Molecular Biology of the Cell, 2008, Garland Science, ISBN 978-0-8153-4105-5.
- Ebuengan, Kaye. "Biomolecules: Classification and structural properties of carbohydrates". Academia.edu.
A monomer ˈ m ɒ n e m er MON e mer mono one mer part is a molecule that can react together with other monomer molecules to form a larger polymer chain or three dimensional network in a process called polymerization IUPAC definition Monomer molecule A molecule which can undergo polymerization thereby contributing constitutional units to the essential structure of a macromolecule ClassificationChemistry classifies monomers by type and two broad classes based on the type of polymer they form By type natural vs synthetic e g glycine vs caprolactam respectively polar vs nonpolar e g vinyl acetate vs ethylene respectively cyclic vs linear e g ethylene oxide vs ethylene glycol respectively By type of polymer they form those that participate in condensation polymerization those that participate in addition polymerization Differing stoichiometry causes each class to create its respective form of polymer This nylon is formed by condensation polymerization of two monomers yielding water The polymerization of one kind of monomer gives a homopolymer Many polymers are copolymers meaning that they are derived from two different monomers In the case of condensation polymerizations the ratio of comonomers is usually 1 1 For example the formation of many nylons requires equal amounts of a dicarboxylic acid and diamine In the case of addition polymerizations the comonomer content is often only a few percent For example small amounts of 1 octene monomer are copolymerized with ethylene to give specialized polyethylene Synthetic monomersEthylene gas H2C CH2 is the monomer for polyethylene Other modified ethylene derivatives include tetrafluoroethylene F2C CF2 which leads to Teflon vinyl chloride H2C CHCl which leads to PVC styrene C6H5CH CH2 which leads to polystyrene Epoxide monomers may be cross linked with themselves or with the addition of a co reactant to form epoxy BPA is the monomer precursor for polycarbonate Terephthalic acid is a comonomer that with ethylene glycol forms polyethylene terephthalate Dimethylsilicon dichloride is a monomer that upon hydrolysis gives polydimethylsiloxane Ethyl methacrylate is an acrylic monomer that when combined with an acrylic polymer catalyzes and forms an acrylate plastic used to create artificial nail extensionsBiopolymersThe term monomeric protein may also be used to describe one of the proteins making up a multiprotein complex Natural monomersSome of the main biopolymers are listed below Amino acids For proteins the monomers are amino acids Polymerization occurs at ribosomes Usually about 20 types of amino acid monomers are used to produce proteins Hence proteins are not homopolymers Nucleotides For polynucleic acids DNA RNA the monomers are nucleotides each of which is made of a pentose sugar a nitrogenous base and a phosphate group Nucleotide monomers are found in the cell nucleus Four types of nucleotide monomers are precursors to DNA and four different nucleotide monomers are precursors to RNA Glucose and related sugars For carbohydrates the monomers are monosaccharides The most abundant natural monomer is glucose which is linked by glycosidic bonds into the polymers cellulose starch and glycogen Isoprene Isoprene is a natural monomer that polymerizes to form a natural rubber most often cis 1 4 polyisoprene but also trans 1 4 polymer Synthetic rubbers are often based on butadiene which is structurally related to isoprene See alsoProtein subunit List of publications in polymer chemistry PrepolymerNotesYoung R J 1987 Introduction to Polymers Chapman amp Hall ISBN 0 412 22170 5 International Union of Pure and Applied Chemistry et al 2000 IUPAC Gold Book Polymerization Clayden Jonathan Greeves Nick Warren Stuart Wothers Peter 2001 Organic Chemistry 1st ed Oxford University Press pp 1450 1466 ISBN 978 0 19 850346 0 Jenkins A D Kratochvil P Stepto R F T Suter U W 1996 Glossary of basic terms in polymer science IUPAC Recommendations 1996 Pure and Applied Chemistry 68 12 2287 2311 doi 10 1351 pac199668122287 D Margerison G C East J E Spice 1967 An Introduction to Polymer Chemistry Pergamon Press ISBN 978 0 08 011891 8 Bruce Alberts Alexander Johnson Julian Lewis Otin Raff Keith Roberts and Peter Walter Molecular Biology of the Cell 2008 Garland Science ISBN 978 0 8153 4105 5 Ebuengan Kaye Biomolecules Classification and structural properties of carbohydrates Academia edu
