Editing Polymer (section)

==Common examples==
{{See also|Polymer classes (disambiguation){{!}}Polymer classes}}

[[File:Styrene-butadiene chain2.png|thumb|left|Structure of a [[styrene-butadiene]] chain, from a molecular simulation]]

Polymers are of two types: naturally occurring and synthetic or ''man made''.

===Natural===
[[Natural polymer|Natural polymeric materials]] such as [[hemp]], [[shellac]], [[amber]], [[wool]], [[silk]], and natural [[rubber]] have been used for centuries. A variety of other natural polymers exist, such as [[cellulose]], which is the main constituent of wood and paper.

====Space polymer====
[[Hemoglycin]] (previously termed [[hemolithin]]) is a space polymer that is the first polymer of [[amino acid]]s found in [[meteorite]]s.<ref name="MPS-2015">{{cite journal|last1=McGeoch|first1=J.E.M.|last2=McGeoch|first2=M.W.|date=2015|title=Polymer amide in the Allende and Murchison meteorites.|journal=[[Meteoritics & Planetary Science]]|volume=50|pages=1971–1983|bibcode=2015M&PS...50.1971M|doi=10.1111/maps.12558|number=12|s2cid=97089690|doi-access=free}}</ref><ref name="SR-20220928">{{cite journal |last1=McGeogh |first1=Julie E. M. |last2=McGeogh |first2=Malcolm W. |title=Chiral 480nm absorption in the hemoglycin space polymer: a possible link to replication |date=28 September 2022 |journal=[[Scientific Reports]] |volume=12 |issue=1 |page=16198 |doi=10.1038/s41598-022-21043-4 |pmid=36171277 |pmc=9519966 }}</ref><ref name="SD-20210629">{{cite news |author=Staff |title=Polymers in meteorites provide clues to early solar system |url=https://www.sciencedaily.com/releases/2021/06/210629120835.htm |date=29 June 2021 |work=[[Science Digest]] |access-date=9 January 2023 }}</ref>

===Synthetic===
The [[list of synthetic polymers]], roughly in order of worldwide demand, includes [[polyethylene]], [[polypropylene]], [[polystyrene]], [[polyvinyl chloride]], [[synthetic rubber]], [[phenol formaldehyde resin]] (or [[Bakelite]]), [[neoprene]], [[nylon]], [[polyacrylonitrile]], [[polyvinyl butyral|PVB]], [[silicone]], and many more. More than 330 million tons of these polymers are made every year (2015).<ref>{{cite web| url = https://committee.iso.org/files/live/sites/tc61/files/The%20Plastic%20Industry%20Berlin%20Aug%202016%20-%20Copy.pdf| title = World Plastics Production}}</ref>

Most commonly, the continuously linked backbone of a polymer used for the preparation of plastics consists mainly of [[carbon]] atoms. A simple example is polyethylene ('polythene' in British English), whose repeat unit or monomer is [[ethylene]]. Many other structures do exist; for example, elements such as silicon form familiar materials such as silicones, examples being [[Silly Putty]] and waterproof plumbing sealant. [[Oxygen]] is also commonly present in polymer backbones, such as those of [[polyethylene glycol]], [[polysaccharide]]s (in [[glycosidic bond]]s), and [[DNA]] (in [[phosphodiester bond]]s).