Editing Polypropylene (section)

====Degradation====
[[File:Failedrope1.jpg|thumb|Effect of UV exposure on polypropylene rope]]
Polypropylene is liable to chain degradation from exposure to temperatures above 100&nbsp;°C. Oxidation usually occurs at the [[tertiary carbon]] centers leading to chain breaking via reaction with [[oxygen]]. In external applications, degradation is evidenced by cracks and [[crazing]]. It may be protected by the use of various [[polymer stabilizers]], including UV-absorbing additives and [[anti-oxidant]]s such as phosphites (e.g. [[tris(2,4-di-tert-butylphenyl)phosphite]]) and hindered phenols, which prevent [[polymer degradation]].<ref name=Ullmanns/>

Microbial communities isolated from soil samples mixed with starch have been shown to be capable of degrading polypropylene.<ref>{{cite journal |pmid=8285678 |pmc=182519 |year=1993 |last1=Cacciari |first1=I |title=Isotactic polypropylene biodegradation by a microbial community: Physicochemical characterization of metabolites produced |journal=Applied and Environmental Microbiology |volume=59 |issue=11 |pages=3695–700 |last2=Quatrini |first2=P |last3=Zirletta |first3=G |last4=Mincione |first4=E |last5=Vinciguerra |first5=V |last6=Lupattelli |first6=P |last7=Giovannozzi Sermanni |first7=G |doi=10.1128/AEM.59.11.3695-3700.1993 |bibcode=1993ApEnM..59.3695C }}</ref>
Polypropylene has been reported to degrade while in the human body as implantable mesh devices. The degraded material forms a tree bark-like layer at the surface of mesh fibers.<ref name="Iakovlev et al 2017">{{cite journal |doi=10.1002/jbm.b.33502 |pmid=26315946 |title=Degradation of polypropylene in vivo: A microscopic analysis of meshes explanted from patients |journal=Journal of Biomedical Materials Research Part B: Applied Biomaterials |volume=105 |issue=2 |pages=237–48 |year=2017 |last1=Iakovlev |first1=Vladimir V |last2=Guelcher |first2=Scott A |last3=Bendavid |first3=Robert }}</ref>