Abstract:
Antioxidants (AOs) are added to minimize or remove the degradation ability of rubber in rubber
compounding. Due to the drawbacks of currently available commercial AOs, the replacement of
a natural AO with dry rubber composites gained attention. In this study Moringa oleifera leaves
methanol extraction and its modified version with ascorbic acid was applied as AO for dry rubber and its physio-mechanical properties, chemical properties, thermal properties, ultra violet
resistivity and morphological behaviour were compared with commercially available AOs, such
as N-isopropyl - N’- phenyl-p-phenylenediamine (IPPD), 2,2,4- trimethyl-1,2-dihydroquinoline
polymer (TMQ), and 2-2’-methylenebis(6- (1-methylcyclohexyl)-P-cresol (WSP). Dry rubber
composite without any AO is considered as the reference composite. Evaluation of the ageing
properties of the dry rubber composites of modified version and natural AO used one showed
that the highest retention of the tensile strength with respect to natural AO and modified version. By comparing 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging ability of the most
popular commercially available AO of IPPD, polar extraction of Moringa oleifera leaves and
its modified version, lowest value of DPPH scavenging ability was shown by the IPPD. Based
on the results of above-mentioned characterizations, we can conclude that the polar extraction
of Moringa oleifera leaves and its modified version has superior AO properties than the commercially available AOs for the dry rubber composites.
