OZONE REACTION WITH C-60 FULLERENE - A STUDY ON THE ANTIOZONANT ACTIVITY OF C-60 FULLERENE IN DIENIC RUBBER

摘要

The reaction between C-60 fullerene and O-3 has been studied in CCl4. The ozonization reaction has been followed by UV-VIS spectroscopy and the formation of fullerene oxides C-60 O-n (n = 1,2...5) observed in the early stages of reaction as indicated by the growth of a new band at 485 nm. These oxides are formed after the scission of intermediate ozonides presumably formed. At the end of ozonization, yellowish to brown fluffy gels, insoluble in carbon tetrachloride but soluble in absolute ethanol or acetone, are recovered. They are composed of polymeric ozonides of C-60. The UV spectrum of these substances in ethanol shows only a broad maximum at 220 nm. The dried substance examined by FT-IR spectroscopy shows extensive oxidation and fullerene cage breakdown. The tarry products are rich in keto, aldehydic and carboxylic groups. The possible antiozonant activity of C-60 fullerene has been estimated in cis-1,4-polyisoprene. The study was conducted by measuring the viscosity change undergone by a standard solution of cis-1,4-polyisoprene in CCl4 in the presence of C-60 without any protection, or in the presence of a commercial antiozonant (p-phenylenediamine-based). Contrary to expectations, the results show that cis-1,4-polyisoprene acts as an ozone scavenger and protects C-60 from ozone attack. [References: 20]