ABSTRACT: Phenol was chemically attached to low molecular weight
chlorinated polyisobutylene and stearic acid respectively. These phenolic
antioxidants were characterised by IR, 1H NMR and TGA. The efficiency and
permanence of these bound antioxidants were compared with conventional
antioxidants in natural rubber vulcanisates. The vulcanisates showed comparable
ageing resistance in comparison to vulcanisates containing conventional
antioxidants. The presence of liquid polymer bound phenol reduce the amount of
plasticiser required for compounding.
Para-phenylenediamine (PD) was chemically attached to depolymerized natural rubber by
a photochemical reaction . The rubber bound PD was characterized by TLC, 1H-NMR, IR,
and TGA. The efficiency and permanence of the bound PD were compared with conventional
antioxidants in NBR vulcanizates . The rubber bound PD was found to be less volatile and
more resistant to water and oil extraction . The vulcanizates showed improved aging resistance
in comparison to vulcanizates containing conventional antioxidants. The liquid rubber
bound antioxidant reduces the amount of plasticizer required for compounding