Polyvinyl alcohol

{{distinguish|polyvinyl acetate}} {{Use dmy dates|date=March 2026}} {{chembox | Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 464210395 | Name = | ImageFile = Polyvinyl Alcohol Structural Formula V1.svg | ImageSize = 150px | ImageFile1 = Sample of Polyvinyl alcohol.jpg | ImageSize1 = 120px | IUPACName = | OtherNames = PVOH; Poly(Ethenol), Ethenol, homopolymer; PVA; Polyviol; Vinol; Alvyl; Alcotex; Covol; Gelvatol; Lemol; Mowiol; Mowiflex, Alcotex, Elvanol, Gelvatol, Lemol, Nelfilcon A, Polyviol und Rhodoviol | SystematicName = | Section1 = {{Chembox Identifiers | CASNo_Ref = {{cascite|correct|CAS}} | CASNo = 9002-89-5 | UNII_Ref = {{fdacite|correct|FDA}} | UNII = 1E30GE2EF7 | PubChem = | ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}} | ChemSpiderID = none | ChEMBL_Ref = {{ebicite|changed|EBI}} | ChEMBL = 76101 | RTECS =TR8100000 | SMILES = | KEGG_Ref = {{keggcite|changed|kegg}} | KEGG = C00980 }} | Section2 = {{Chembox Properties | Formula = (C₂H₄O)_x | MolarMass = | Appearance = | Density = 1.19–1.31 g/cm³ | MeltingPtC = 200 | Solubility = | RefractIndex = 1.477 @ 632 nm<ref>{{cite journal | vauthors = Schnepf MJ, Mayer M, Kuttner C, Tebbe M, Wolf D, Dulle M, Altantzis T, Formanek P, Förster S, Bals S, König TA, Fery A | display-authors = 3 | title = Nanorattles with tailored electric field enhancement | journal = Nanoscale | volume = 9 | issue = 27 | pages = 9376–9385 | date = July 2017 | pmid = 28656183 | doi = 10.1039/C7NR02952G | doi-access = free | hdl = 10067/1447970151162165141 | hdl-access = free }}</ref> | LogP = }} | Section3 = {{Chembox Hazards | ExternalSDS = [https://www.carlroth.com/medias/SDB-1T2Y-GB-EN.pdf?context=bWFzdGVyfHNlY3VyaXR5RGF0YXNoZWV0c3wyNDkzMjJ8YXBwbGljYXRpb24vcGRmfGFEazFMMmd3WVM4NU1UY3dPREV3TmprNU9EQTJMMU5FUWw4eFZESlpYMGRDWDBWT0xuQmtaZ3w5ZDI2YjllYTFkMjg0ZjE4MTg1OGFhNjY2MjkyMDZjYmU3ZDY2OWJjNDlhNjM3ZDcyYmY1OWVlYTk4OGY3MjM0 External MSDS] | MainHazards = | NFPA-H = 0 | NFPA-F = 1 | NFPA-R = 0 | NFPA-S = | FlashPtC = 79.44 | AutoignitionPtC = | LD50 =14,700 mg/kg (mouse) }} | Section4 = | Section5 = | Section6 = }}

'''Polyvinyl alcohol''' ('''PVOH''', '''PVA''', or '''PVAl''') is a water-soluble synthetic polymer. It has the idealized formula [CH₂CH(OH)]_''n''. It is used in papermaking, textile warp sizing, as a thickener and emulsion stabilizer in polyvinyl acetate (PVAc) adhesive formulations, in a variety of coatings, and 3D printing. It is colourless (white) and odorless. It is commonly supplied as beads or as solutions in water.<ref name=Ullmann/><ref>{{cite journal | vauthors = Tang X, Alavi S |doi=10.1016/j.carbpol.2011.01.030 |title=Recent Advances in Starch, Polyvinyl Alcohol Based Polymer Blends, Nanocomposites and Their Biodegradability |journal=Carbohydrate Polymers |volume=85 |pages=7–16 |year=2011 }}</ref> Without an externally added crosslinking agent, PVA solution can be gelled through repeated freezing-thawing, yielding highly strong, ultrapure, biocompatible hydrogels which have been used for a variety of applications, such as vascular stents, cartilages, contact lenses, etc.<ref>{{Cite journal|last1=Adelnia|first1=Hossein|last2=Ensandoost|first2=Reza|last3=Shebbrin Moonshi|first3=Shehzahdi|last4=Gavgani|first4=Jaber Nasrollah|last5=Vasafi|first5=Emad Izadi|last6=Ta|first6=Hang Thu|display-authors=3|date=5 February 2022|title=Freeze/thawed polyvinyl alcohol hydrogels: Present, past and future|url=https://www.sciencedirect.com/science/article/pii/S0014305721007084|journal=European Polymer Journal|language=en|volume=164|article-number=110974|doi=10.1016/j.eurpolymj.2021.110974|bibcode=2022EurPJ.16410974A |s2cid=245576810 |issn=0014-3057|hdl=10072/417476|hdl-access=free}}</ref>

Although polyvinyl alcohol is often referred to by the acronym PVA, more generally PVA refers to polyvinyl acetate, which is commonly used as a wood adhesive and sealer.

==Uses== PVA is used in a variety of medical applications because of its biocompatibility, low tendency for protein adhesion, and low toxicity. Specific uses include cartilage replacements, contact lenses, laundry detergent pods and eye drops.<ref>{{cite journal |vauthors = Baker MI, Walsh SP, Schwartz Z, Boyan BD |title = A review of polyvinyl alcohol and its uses in cartilage and orthopedic applications |journal = Journal of Biomedical Materials Research Part B: Applied Biomaterials |volume = 100 |issue = 5 |pages = 1451–7 |date = July 2012 |pmid = 22514196 |doi = 10.1002/jbm.b.32694 }}</ref> Polyvinyl alcohol is used as an aid in suspension polymerizations. Its largest application in China is its use as a protective colloid to make PVAc dispersions. In Japan its major use is the production of Vinylon fiber.<ref name="sri">[http://www.sriconsulting.com/CEH/Public/Reports/580.1810/ SRI Consulting CEH Report Polyvinyl Alcohol], published March 2007, abstract retrieved 30 July 2008.</ref> This fiber is also manufactured in North Korea for self-sufficiency reasons, because no oil is required to produce it. Another application is photographic film.<ref>{{Cite book |title=Characterization and Failure Analysis of Plastics |chapter=Effects of Composition, Processing, and Structure on Properties of Engineering Plastics|editor-last=Lampman |editor-first=Steve |publisher=ASM International |year=2003 |page=29|doi=10.31399/asm.tb.cfap.t69780028|isbn=978-0-87170-789-5}}</ref>

PVA-based polymers are used widely in additive manufacturing. For example, 3D printed oral dosage forms demonstrate great potential in the pharmaceutical industry. It is possible to create drug-loaded tablets with modified drug-release characteristics where PVA is used as a binder substance.<ref>{{cite journal |vauthors = Xu X, Zhao J, Wang M, Wang L, Yang J |display-authors=3|title = 3D Printed Polyvinyl Alcohol Tablets with Multiple Release Profiles |journal = Scientific Reports |volume = 9 |issue = 1 |article-number = 12487 |date = August 2019 |pmid = 31462744 |pmc = 6713737 |doi = 10.1038/s41598-019-48921-8 |bibcode=2019NatSR...912487X}}</ref>

Medically, PVA-based microparticles have received FDA 510(k) approval to be used as embolisation particles to be used for peripheral hypervascular tumors.<ref>{{Cite web |title=Contour™ - Brief Summary |url=https://www.bostonscientific.com/en-US/products/embolization/contour-pva-embolization-particles/contour-prescriptive-information.html |access-date=11 August 2023 |website=www.bostonscientific.com |language=en-us}}</ref> It may also used as the embolic agent in a Uterine Fibroid Embolectomy (UFE).<ref>{{cite web |title = Uterine Fibroid Embolization and Imaging |url = https://emedicine.medscape.com/article/421734-overview#a4 |vauthors = Siskin GP |veditors = Cho KJ |work=Medscape|publisher = WebMD LLC |archive-url=https://web.archive.org/web/20150304224753/https://emedicine.medscape.com/article/421734-overview#a15 |archive-date=4 March 2015}}</ref> In biomedical engineering research, PVA has also been studied for cartilage, orthopaedic applications,<ref>{{Cite journal |last1=Baker |first1=Maribel I. |last2=Walsh |first2=Steven P. |last3=Schwartz |first3=Zvi |last4=Boyan |first4=Barbara D. |date=July 2012 |title=A review of polyvinyl alcohol and its uses in cartilage and orthopedic applications |url=https://onlinelibrary.wiley.com/doi/10.1002/jbm.b.32694 |journal=Journal of Biomedical Materials Research Part B: Applied Biomaterials |language=en |volume=100B |issue=5 |pages=1451–1457 |doi=10.1002/jbm.b.32694|pmid=22514196 |url-access=subscription }}</ref> and potential materials for vascular graft.<ref>{{Cite journal |last1=Chaouat |first1=Marc |last2=Le Visage |first2=Catherine |last3=Baille |first3=Wilms E. |last4=Escoubet |first4=Brigitte |last5=Chaubet |first5=Frédéric |last6=Mateescu |first6=Mircea Alexandru |last7=Letourneur |first7=Didier |date=9 October 2008 |title=A Novel Cross-linked Poly(vinyl alcohol) (PVA) for Vascular Grafts |url=https://onlinelibrary.wiley.com/doi/10.1002/adfm.200701261 |journal=Advanced Functional Materials |language=en |volume=18 |issue=19 |pages=2855–2861 |doi=10.1002/adfm.200701261|s2cid=42332293 |url-access=subscription }}</ref>

PVA is commonly used in household sponges that absorb more water than polyurethane sponges.{{citation needed|date=August 2024}}

PVA may be used as an adhesive during preparation of stool samples for microscopic examination in pathology.<ref>{{cite journal|last1=Jensen|first1=B.|last2=Kepley|first2=W.|last3=Guarner|first3=J.|last4=Anderson|first4=K.|last5=Anderson|first5=D.|last6=Clairmont|first6=J.|last7=De l'aune|first7=W.|last8=Austin|first8=E.H.|last9=Austin|first9=G.E.|title=Comparison of Polyvinyl Alcohol Fixative with Three Less Hazardous Fixatives for Detection and Identification of Intestinal Parasites|journal=Journal of Clinical Microbiology|volume=38|issue=4|pages=1592–1598|doi=10.1128/jcm.38.4.1592-1598.2000|pmc=86497|pmid=10747149|year=2000}}</ref>

===Polyvinyl acetals=== Polyvinyl acetals are prepared by treating PVA with aldehydes. Butyraldehyde and formaldehyde afford polyvinyl butyral (PVB) and polyvinyl formal (PVF), respectively. Preparation of polyvinyl butyral is the largest use for polyvinyl alcohol in the US and Western Europe.

==Preparation== Unlike most vinyl polymers, PVA is not prepared by polymerization of the corresponding monomer, since the monomer, vinyl alcohol, is thermodynamically unstable with respect to its tautomerization to acetaldehyde. Instead, PVA is prepared by hydrolysis of polyvinyl acetate,<ref name=Ullmann>{{Ullmann |first1=Manfred L. |last1=Hallensleben| name-list-style = vanc |title=Polyvinyl Compounds, Others |year=2000 |doi=10.1002/14356007.a21_743}}</ref> or sometimes other vinyl ester-derived polymers with formate or chloroacetate groups instead of acetate. The conversion of the polyvinyl esters is usually conducted by base-catalysed transesterification with ethanol: : [CH₂CH(OAc)]_''n'' + C₂H₅OH → [CH₂CH(OH)]_''n'' + C₂H₅OAc

The properties of the polymer are affected by the degree of transesterification.

Worldwide consumption of polyvinyl alcohol was over one million metric tons in 2006.<ref name="sri"/>

==Structure and properties== PVA is an atactic material that exhibits crystallinity. In terms of microstructure, it is composed mainly of 1,3-diol linkages [−CH₂−CH(OH)−CH₂−CH(OH)−], but a few percent of 1,2-diols [−CH₂−CH(OH)−CH(OH)−CH₂−] occur, depending on the conditions for the polymerization of the vinyl ester precursor.<ref name=Ullmann/>

Polyvinyl alcohol has excellent film-forming, emulsifying and adhesive properties. It is also resistant to oil, grease and solvents. It has high tensile strength and flexibility, as well as high oxygen and aroma barrier properties. However, these properties are dependent on humidity: water absorbed at higher humidity levels acts as a plasticiser, which reduces the polymer's tensile strength, but increases its elongation and tear strength.

==Safety and environmental considerations== Polyvinyl alcohol is widely used, thus its toxicity and biodegradation are of interest. Tests showed that fish (guppies) are not harmed, even at a poly(vinyl alcohol) concentration of 500 mg/L of water.<ref name=Ullmann/>

The biodegradability of PVA is affected by the molecular weight of the sample.<ref name=Ullmann/> Aqueous solutions of PVA degrade faster, which is why PVA grades that are highly water-soluble tend to have a faster biodegradation.<ref>{{cite journal | vauthors = Kawai F, Hu X |title= Biochemistry of microbial polyvinyl alcohol degradation |journal=Applied Microbiology and Biotechnology |volume=84 |issue=2 |pages=227–37 |date= August 2009 |pmid= 19590867 |doi= 10.1007/s00253-009-2113-6 |s2cid= 25068302 }}</ref> Not all PVA grades are readily biodegradable, but studies show that high water-soluble PVA grades such as the ones used in detergents can be readily biodegradable according to OECD screening test conditions.<ref>{{cite journal |last1=Byrne |first1=Dominic |last2=Boeije |first2=Geert |last3=Croft |first3=Ian |last4=Hüttmann |first4=Gerd |last5=Luijkx |first5=Gerard |last6=Meier |first6=Frank |last7=Parulekar |first7=Yash |last8=Stijntjes |first8=Gerard |date=13 March 2021 |title=Biodegradability of Polyvinyl Alcohol Based Film Used for Liquid Detergent Capsules: Biologische Abbaubarkeit der für Flüssigwaschmittelkapseln verwendeten Folie auf Polyvinylalkoholbasis. |url=https://www.degruyterbrill.com/document/doi/10.1515/tsd-2020-2326/html |journal=Tenside Surfactants Detergents |volume=58 |issue=2 |publisher=De Gruyter Brill |pages=88-96 |doi=10.1515/tsd-2020-2326 |doi-access=free |issn=0932-3414 |access-date=14 January 2026}}</ref>

Orally administered PVA is relatively harmless.<ref name="study5">{{cite journal |last1=DeMerlis |first1=C. C. |last2=Schoneker |first2=D. R. |title=Review of the oral toxicity of polyvinyl alcohol (PVA) |journal=Food and Chemical Toxicology |date=March 2003 |volume=41 |issue=3 |pages=319–326 |publisher=Elsevier |doi=10.1016/s0278-6915(02)00258-2 |pmid=12504164 |issn=0278-6915}}</ref> The safety of polyvinyl alcohol is based on some of the following observations:<ref name="study5" /> * The acute oral toxicity of polyvinyl alcohol is very low, with LD(50)s in the range of 15-20 g/kg; * Orally administered PVA is very poorly absorbed from the gastrointestinal tract; * PVA does not accumulate in the body when administered orally; * Polyvinyl alcohol is not mutagenic or clastogenic

== See also == * Polyvinyl nitrate * Vinyl acetate

== References == {{reflist}}

== External links == * [http://hazard.com/msds/mf/baker/baker/files/p5282.htm MSDS] * [https://web.archive.org/web/20110224011317/http://chem.lapeer.org/Chem1Docs/SlimeDemo.html "Slime" recipe] * [http://www.pslc.ws/macrog/iblend.htm Forming PVA layers in PET bottles]

{{Authority control}} Category:Vinyl polymers Category:Biodegradable plastics Category:Polymers Category:E-number additives Category:3D printing materials