Polymer chemistry: Difference between revisions

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'''Polymer chemistry''' or '''[[Macromolecular chemistry]]''' is a multidisciplinary [[science]] that deals with the [[chemical synthesis]] and [[Chemical property|chemical properties]] of [[polymer]]s or [[macromolecule]]s. According to [[IUPAC]] recommendations, macromolecules refer to the individual molecular chains and are the domain of [[chemistry]]. [[Polymer]]s describe the bulk properties of polymer materials and belong to the field of [[polymer physics]] as a subfield of [[physics]].
'''Polymer chemistry''' or '''macromolecular chemistry''' is a multidisciplinary [[science]] that deals with the [[chemical synthesis]] and [[Chemical property|chemical properties]] of [[polymer]]s or [[macromolecule]]s.
*[[Biopolymer]]s produced by living organisms:
**structural [[protein]]s: [[collagen]], [[keratin]], [[elastin]]…
**[[chemical reaction|chemically functional]] proteins: [[enzyme]]s, [[hormone]]s, [[transport protein]]s…
**structural [[polysaccharide]]s: [[cellulose]], [[chitin]]…
**storage polysaccharides: [[starch]], [[glycogen]]…
**[[nucleic acid]]s: [[DNA]], [[RNA]]
*[[chemical synthesis|Synthetic]] polymers used for [[plastic]]s — [[fiber]]s, [[paint]]s, [[building material]]s, [[furniture]], [[machine|mechanical parts]], [[adhesive]]s:
**[[thermoplastic]]s: [[polyethylene]], [[Teflon]] [[polystyrene]], [[polypropylene]], [[polyester]], [[polyurethane]], [[polymethyl methacrylate]], [[polyvinyl chloride]], [[nylon]], [[rayon]], [[celluloid]], [[silicone]], [[fiberglass]]…
**[[thermosetting plastic]]s: [[vulcanization|vulcanized]] [[rubber]], [[Bakelite]], [[Kevlar]], [[epoxy]]…


Polymers form by [[polymerization]] of [[monomer]]s. A polymer is chemically described by its [[degree of polymerisation]], [[molar mass distribution]], [[tacticity]], [[copolymer]] distribution, the degree of [[branching]], by its [[end-group]]s,  [[cross-link|crosslinks]], [[crystallinity]] and thermal properties such as its [[glass transition temperature]] and melting temperature. Polymers in [[solution]] have special characteristics with respect to [[solubility]], [[viscosity]] and [[gel|gelation]].
== History ==


== History ==
The earliest work in modern polymer chemistry involved the chemical modification of naturally occuring polymers.  The reaction between nitric acid and cellulose, studied by [[Henri Braconnot]] in 1832 and later by [[Christian Schönbein]], led to the discovery of [[nitrocellulose]] and [[celluloid]].  The ensuing years saw the preparation of other cellulose derivatives, such as  [[collodion]], used as a [[wound]] dressing since the [[American Civil War|U.S. Civil War]], and [[cellulose acetate]], first prepared in 1865.
 
Other early work in polymer chemistry involved the modification of natural rubber to improve durability.  In 1834, [[Friedrich Ludersdorf]] and [[Nathaniel Hayward]] independently [[plastic|discovered]] that adding sulfur to raw natural [[rubber]] ([[isoprene|polyisoprene]]) helped prevent the material from becoming sticky. In 1844 [[Charles Goodyear]] received a U.S. patent for [[vulcanization|vulcanizing]] rubber with [[sulfur]] and heat. [[Thomas Hancock]] had received a patent for the same process in the U.K. the year before.


The work of [[Henri Braconnot]] in 1832 and [[Christian Schönbein]] in1846 led to the discovery of [[nitrocellulose]], which, when treated with [[camphor]] produced [[celluloid]]. Dissolved in [[ether]] or [[acetone]], it is [[collodion]], used as a [[wound]] dressing since the [[American Civil War|U.S. Civil War]]. [[Cellulose acetate]] was first prepared in 1865. In 1834, [[Friedrich Ludersdorf]] and [[Nathaniel Hayward]] independently [[plastic|discovered]] that adding sulfur to raw natural [[rubber]] ([[isoprene|polyisoprene]]) helped prevent the material from becoming sticky. In 1844 [[Charles Goodyear]] received a U.S. patent for [[vulcanization|vulcanizing]] rubber with [[sulfur]] and heat. [[Thomas Hancock]] had received a patent for the same process in the U.K. the year before.
In 1884 [[Hilaire de Chardonnet]] started the first artificial [[fiber]] plant based on regenerated [[cellulose]], or [[viscose]] [[rayon]], as a substitute for [[silk]], but it was very flammable.[http://www.plastiquarian.com/top.htm] In [[1907]] [[Leo Baekeland]] invented the first wholly [[chemical synthesis|synthetic]] polymer, a [[thermoset]]ting [[phenol]]-[[formaldehyde]] resin called [[Bakelite]]. [[Cellophane]] was invented in 1908 by [[Jocques Brandenberger]] who squirted sheets of viscose rayon into an [[acid]] bath.[http://inventors.about.com/library/inventors/blcellophane.htm]


In 1884 [[Hilaire de Chardonnet]] started the first artificial [[fiber]] plant based on regenerated [[cellulose]], or [[viscose]] [[rayon]], as a substitute for [[silk]], but it was very flammable.[http://www.plastiquarian.com/top.htm] In [[1907]] [[Leo Baekeland]] invented the first [[chemical synthesis|synthetic]] polymer, a [[thermoset]]ting [[phenol]]-[[formaldehyde]] resin called [[Bakelite]]. [[Cellophane]] was invented in 1908 by [[Jocques Brandenberger]] who squirted sheets of viscose rayon into an [[acid]] bath.[http://inventors.about.com/library/inventors/blcellophane.htm] In 1922 [[Hermann Staudinger]] was the first to propose that polymers consisted of long chains of [[atoms]] held together by [[covalent bond]]s. He also proposed to name these compounds [[macromolecule]]s. Before that, [[scientist]]s believed that polymers were clusters of small [[molecule]]s (called [[colloid]]s), without definite [[molecular mass|molecular weights]], held together by an unknown [[force]]. Staudinger received the [[Nobel Prize in Chemistry]] in 1953. [[Wallace Carothers]] invented the first synthetic rubber called [[neoprene]] in 1931, the first [[polyester]], and went on to invent [[nylon]], a true silk replacement, in 1935. [[Paul Flory]] was awarded the [[Nobel Prize in Chemistry]] in 1974 for his work on polymer [[random coil]] configurations in solution in the 1950s. [[Stephanie Kwolek]] developed an [[aramid]], or [[aromatic]] nylon named [[Kevlar]], patented in 1966.
The work of [[Wallace Carothers]] in the 1930s demonstrated that polymers of desired chain length and composition could be synthesized rationally from constituent monomers, laying the foundations of modern polymer chemistry and laying the framework for the now burgeoning polymer industry. Carothers is credited with the development of [[neoprene]] (1931), a synthetic rubber, the first [[polyester]], and [[nylon]] (1935), a true silk replacement.   The work of Ziegler and Natta in the 1950s laid the basis for stereospecific polymer synthesis. [[Stephanie Kwolek]] developed an [[aramid]], or [[aromatic]] nylon named [[Kevlar]], patented in 1966.


There are now a large number of [[commerce|commercial]] polymers, including [[composite material]]s such as [[carbon fiber]]-[[epoxy]], [[polystyrene]]-[[polybutadiene]] (HIPS), [[acrylonitrile]]-[[butadiene]]-[[styrene]] (ABS), and other such materials that combine the best properties of their various components, including polymers designed to work at high [[temperature]]s in [[automobile]] [[engine]]s.
There are now a large number of [[commerce|commercial]] polymers, including [[composite material]]s such as [[carbon fiber]]-[[epoxy]], [[polystyrene]]-[[polybutadiene]] (HIPS), [[acrylonitrile]]-[[butadiene]]-[[styrene]] (ABS), and other such materials that combine the best properties of their various components, including polymers designed to work at high [[temperature]]s in [[automobile]] [[engine]]s.

Revision as of 01:17, 3 April 2007

Polymer chemistry or macromolecular chemistry is a multidisciplinary science that deals with the chemical synthesis and chemical properties of polymers or macromolecules.

History

The earliest work in modern polymer chemistry involved the chemical modification of naturally occuring polymers. The reaction between nitric acid and cellulose, studied by Henri Braconnot in 1832 and later by Christian Schönbein, led to the discovery of nitrocellulose and celluloid. The ensuing years saw the preparation of other cellulose derivatives, such as collodion, used as a wound dressing since the U.S. Civil War, and cellulose acetate, first prepared in 1865.

Other early work in polymer chemistry involved the modification of natural rubber to improve durability. In 1834, Friedrich Ludersdorf and Nathaniel Hayward independently discovered that adding sulfur to raw natural rubber (polyisoprene) helped prevent the material from becoming sticky. In 1844 Charles Goodyear received a U.S. patent for vulcanizing rubber with sulfur and heat. Thomas Hancock had received a patent for the same process in the U.K. the year before.

In 1884 Hilaire de Chardonnet started the first artificial fiber plant based on regenerated cellulose, or viscose rayon, as a substitute for silk, but it was very flammable.[1] In 1907 Leo Baekeland invented the first wholly synthetic polymer, a thermosetting phenol-formaldehyde resin called Bakelite. Cellophane was invented in 1908 by Jocques Brandenberger who squirted sheets of viscose rayon into an acid bath.[2]

The work of Wallace Carothers in the 1930s demonstrated that polymers of desired chain length and composition could be synthesized rationally from constituent monomers, laying the foundations of modern polymer chemistry and laying the framework for the now burgeoning polymer industry. Carothers is credited with the development of neoprene (1931), a synthetic rubber, the first polyester, and nylon (1935), a true silk replacement. The work of Ziegler and Natta in the 1950s laid the basis for stereospecific polymer synthesis. Stephanie Kwolek developed an aramid, or aromatic nylon named Kevlar, patented in 1966.

There are now a large number of commercial polymers, including composite materials such as carbon fiber-epoxy, polystyrene-polybutadiene (HIPS), acrylonitrile-butadiene-styrene (ABS), and other such materials that combine the best properties of their various components, including polymers designed to work at high temperatures in automobile engines.

External links