Pimsuda Heamtanon. Improvement of adhesion between natural rubber and nitrile rubber by using adhesion promoter compound based on chlorosulfonated polyethylene and chlorinated natural rubber . Master's Degree(Polymer Science and Technology). Mahidol University. : Mahidol University, 2005.
Improvement of adhesion between natural rubber and nitrile rubber by using adhesion promoter compound based on chlorosulfonated polyethylene and chlorinated natural rubber
Abstract:
Natural Rubber (NR) possesses good dynamic and mechanical properties.
However, some of its properties such as oil resistance and weathering resistance are
much lower than those of synthetic rubbers. Encasing NR with nitrile rubber (NBR) is
one way of combining good properties of the two rubbers. This idea could be applied
for various kinds of products, for example, hoses for transportation of oil, bridge
bearings, fenders for docks and boats. However, what is required is good adhesion
between NR and synthetic rubbers.
This project studied the factors influencing the adhesion of NR and NBR. The
adhesion promoter compound (APC) was formulated and used in solution and solid
form. The role of each component in this compound was studied. The adhesive
strength from a T-peel test was found to increase with increasing amounts of the active
components (p-benzoquinonedioxime (BQD), N, N′-m-phenylenebismaleimide
(HVA-2) and PbO2) in APC. Chlorosulfonated polyethylene (CSPE) and chlorinated
natural rubber (CNR) were found to be necessary components and could not be
replaced by polychloroprene (CR). In solid form, APC was prepared prior to
incorporating it into NR and NBR to study its effectiveness in improving the bonding
of NR//NBR. The cohesive failure (peel strength > 104 J/m2) was found with inclusion
of APC 40 and 60 phr in NBR. Incorporation of APC in the NR phase caused
scorching of the compound when greater than 20 phr of APC was used. The
investigation of the surface property of APC-NBR blend under Atomic Force
Microscopy (AFM) found the adhesive force of tip-surface increased as a function of
the amount of APC. This shows that APC contributes to the adhesive strength of
NR//NBR. The storage of APC-NBR showed the decrease in the adhesive strength due
to pre-crosslinking which was proven by a smaller torque difference of cure test. IR
investigation of stored samples illustrated the formation of oxidation product from
BQD in NBR compound. The addition of CSPE in NR at 60 phr showed the cohesive
failure in a peel test of NR//NBR because the chlorine (Cl) in CNR and
chlorosulfonate (SO2Cl) groups in CSPE could chemically react with acrylonitrile (CN)
of NBR resulting in excellent bonding of NR//NBR.