Cigarette Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.Anti-spam check. Do not fill this in! === Photodegradation === The other process of degradation is [[photodegradation]], which is when a molecular bond is broken by the absorption of photon radiation (i.e. light). Due to cellulose acetate carbonyl groups, the molecule naturally absorbs light at 260 nm,<ref>{{Cite journal |author=Hon NS |title=Photodegradation of Cellulose Acetate Fibers |journal=Journal of Polymer Science Part A: Polymer Chemistry |volume=15 |issue=3 |pages=725–744 |date=1977 |doi=10.1002/pol.1977.170150319|bibcode=1977JPoSA..15..725H }}</ref> but it contains some impurities which can absorb light. These impurities are known to absorb light in the far UV light region (< 280 nm).<ref>{{Cite journal |vauthors=Hosono K, Kanazawa A, Mori H, Endo T |title=Photodegradation of Cellulose Acetate film in the presence of bensophenone as a photosensitizer |journal=Journal of Applied Polymer Science |volume=105 |issue=6 |pages=3235–3239 |date=2007 |doi=10.1002/app.26386|doi-access=free }}</ref> The atmosphere filters radiation from the sun and allows radiation of > 300 nm only to reach the surface. Thus, the primary photodegradation of cellulose acetate is considered insignificant to the total degradation process, since cellulose acetate and its impurities absorb light at shorter wavelengths. Research is focused on the secondary mechanisms of photodegradation of cellulose acetate to help make up for some of the limitations of biodegradation. The secondary mechanisms would be the addition of a compound to the filters that would be able to absorb natural light and use it to start the degradation process. The main two areas of research are in photocatalytic oxidation<ref>{{cite web |url=http://allergyclean.com/news/uvpcoformaldehyde.htm |title=Study on Photocatalytic Oxidation (PCO) Raises Questions About Formaldehyde as a Byproduct in Indoor Air |access-date=May 30, 2015 |archive-url=https://web.archive.org/web/20150426065810/http://allergyclean.com/news/uvpcoformaldehyde.htm |archive-date=April 26, 2015 }}</ref> and photosensitized degradation.<ref>{{cite encyclopedia|url=https://www.britannica.com/EBchecked/topic/458153/photosensitization|title=photosensitization - chemistry|encyclopedia=Encyclopædia Britannica|access-date=May 30, 2015}}</ref> Photocatalytic oxidation uses a species that absorbs radiation and creates hydroxyl radicals that react with the filters and start the breakdown. Photosensitized degradation, though, uses a species that absorbs radiation and transfers the energy to the cellulose acetate to start the degradation process. Both processes use other species that absorbed light > 300 nm to start the degradation of cellulose acetate.{{citation needed|date=December 2014}} Summary: Please note that all contributions to Christianpedia may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here. You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see Christianpedia:Copyrights for details). Do not submit copyrighted work without permission! Cancel Editing help (opens in new window) Discuss this page