Photocatalytic degradation of epoxidized natural rubber latex using hydrogen peroxide and TiO 2 nanocrystal

A characteristic chain cleavage in epoxidized natural rubber (ENR) is similar to the natural rubber (NR), where the chain is oxidized and cleaved. The bond cleavage in ENR could occur in both oxirane and double bond groups, depending on the method used. In this work, 50% mol epoxidized natural rubber (ENR50) was degraded under ultraviolet (UV) light in latex state to yield low molecular weight ENR50 (LENR). ENR50 latex was subjected to UV light in the presence of hydrogen peroxide (H 2 O 2 ) as a reagent and titanium dioxide (TiO 2 ) as a photocatalyst. The properties of the sample were characterized using gel permeation chromatography (GPC), Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR). The results showed ENR50 latex can be degraded under UV light. The degradation was accelerated in the presence of H 2 O 2 and TiO 2 , which then determined the chemical structure of LENR. The molecular weight of ENR50 significantly reduced from 161.77 × 10 3 g/mol to 14.57 × 10 3 and 6.40 × 10 3 g/mol after 24 and 48 h of photodegradation, respectively. Chain breaking was found to be dominant in the olefinic (C = C) group, whilst the epoxide group was not affected. The presence of TiO 2 did not affect the efficiency of the degradation reaction but induced the opening of the epoxy group. These were confirmed from FTIR and NMR spectroscopy analyses, whereby the degraded sample showed the presence of carbonyl and hydroxyl groups, resulted from the chain breaking and ring opening. Graphical abstract