Some aspects of stabilization and degradation of nigerian natural rubber. I. Photostabilization of natural rubber with bound di‐tert‐butyl‐4‐hydroxybenzyl thioglycollate (dbhbt)

Abstract

Abstract3,5‐Di‐tert‐butyl‐4‐hydroxybenzyl thioglycollate (DBHBT) has been reacted with Nigerian Natural rubber latex at 65 ± 1°C using 4,4‐azobiscyanovaleric (AZBN) acid‐ferrous sulfate redox system to obtain a binding efficiency of 13%. The bound DBHBT was investigated as a UV stabilizer in unprocessed and unvulcanized rubber using spectroscopic method. With respect to the CO index, the masterbatch diluted to 56% gave the optimum activity and higher concentrations showed significant pro‐oxidant activity. The CC bonds in particular, showed greater stability which is a function of DBHBT concentration. The methylenic and the allylic hydrogen atoms, the most susceptible, and probably the sites of the primary attack, were not protected by DBHBT.