الفهرس 
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Abstract
The present work is devoted to the preparation of novel different
aromatic amine moieties and evaluation of their activity as antioxidants for
acrylonitrile-butadiene rubber NBR.
In the first part, 2-propyl-, and 2-heptyl-, 1H-benzo[d]imidazole
(3a,b) were prepared by condensation reaction of o-phenylenediamine (1)
with n-butanoic acid (2a) and n-octanoic acid (2b), respectively. The prepared
products were characterized by FT-IR, 1H-NMR spectroscopy and melting
points. These products were incorporated into (NBR) composites with
two different fillers (Silica and High Abrasion Furnace carbon black “HAF”)
as antioxidant additives at different concentrations from 1 up to 2 phr as
compared to 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) as a commercial
antioxidant. Their effects on the rheometric, physico-mechanical and electrical
properties of NBR composites were evaluated. Thermo-oxidative aging
was carried out for NBR composites and distribution of the prepared
products observed by Scanning Electron Microscope (SEM). Swelling
and crosslinking density for NBR vulcanizates were evaluated and
thermal gravimetric analysis (TGA) for NBR vulcanizates were also
evaluated. The results showed that the prepared products can act as highly
efficient antioxidants in acrylonitrile butadiene rubber vulcanizates comparing
with commercial antioxidant TMQ and revealed that there was enhancement
in mechanical properties of NBR composites that containing the prepared
products, as well. The results also illustrated that the optimum ratio from
2-alkyl benzimidazoles incorporated into acrylonitrile butadiene rubber
vulcanizates is 1.5 phr if compared with the same ratio from commercial
antioxidant (TMQ).
In the second part, 1H-benzo[d][1,2,3]triazole (4) as N- heterocyclic
compound was prepared by ring closure reaction of diazonium salt of ophenylenediamine
(1) by nitrous acid. FT-IR, 1H-NMR spectroscopy and
melting point confirmed the successful preparation of 1H-benzo[d][1,2,3]triazole.
The main objective of this study is to investigate the probability of 1Hbenzo-[
d][1,2,3] triazole to be used as a novel antioxidant for (NBR). The
prepared product filled in NBR composite with different content starting
from 1 to 2 phr as compared to the commercial antioxidant (TMQ). The
mechanical, thermo-oxidative aging and electrical properties of the composites
containing the prepared product were compared with those of composites
having commercial antioxidant in the same content. Distribution of the
antioxidants into composites was observed by (SEM). Swelling and
crosslinking density for NBR vulcanizates and (TGA) analysis for NBR
vulcanizates were also evaluated. The results revealed that 1H-benzo-
[d][1,2,3]triazole can act as highly efficient antioxidant in acrylonitrile
butadiene rubber vulcanizates comparing with commercial antioxidant
TMQ and showed that there was enhancement in mechanical properties
of NBR composites, as well.
Keywords
2-propyl-1H-benzo[d]imidazole, 2-heptyl-1H-benzo[d]imidazole, 1Hbenzo[
d][1,2,3]triazole, 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ),
Antioxidant, Physico-mechanical, Crosslinking density and Electrical
properties