Depolymerisation of nr latex and its applications

Abstract

The controlled molecular weight reduction of NR in latex phase had been carried out by treating NR latex with singlet molecular oxygen generated from inexpensive and nontoxic reagents 'Hydrogen peroxide and sodium hypochlorite' . The extent of degradation was studied by viscosity measurements. The extent to which viscosity is reduced can be controlled to a large extent by the amount of reagents used and the pH of the latex. In acidic medium extent of degradation was higher. The mechanism of scission is investigated. The results obtained are more in favour with the mode of scission proposed by Hock. Potential applications of the process can be grouped in to three general areas corresponding to low, intermediate and high level of treatment. Low level of treatment give rubber of reduced viscosity within the normal range for bulk rubber. Intermediate levels give soft, sticky rubbers pale in colour and showing good pressure sensitive tack and peel strength even without the use of tackyfing resins. High levels of treatment give very viscous liquid rubber.