Study On The Relationship Between Mechanical Properties Of NBR Vulcanizates And Temperature

Nitrile butadiene rubber (NBR) has excellent oil resistance, heat resistance, aging resistance and mechanical properties. It is used in petrochemical industry and automobile with severe environment. Now many studies on the heat resistance and cold resistance of NBR have been done, but mechanical properties of NBR at high temperature has not been done nearly. The study on mechanical properties of NBR vulcanizates at high temperature has an important significance to the use of NBR parts.This paper mainly studied the mechanical properties of NBR with different ACN contents. The experimental results showed that the tensile strength, shore A hardness,tear strength of NBR vulcanizate with different ACN contents increased with the increase of volume fraction of carbon black at room temperature. The tensile strength, shore A hardness, tear strength of NBR vulcanizate with different ACN contents and same carbon black contents decreased with the increase of temperature.This section mainly studied the quantitative relationships between filler contents or different temperatures and mechanical properties of NBR3345. The experimental results showed that the tensile strength, shore A hardness,tear strength of NBR3445vulcanizate increased linearly with the increase of volume fraction of carbon black or silica at room temperature; At125℃temperature, the change rule of mechanical properties of NBR filled with silica was the same as that at room temperature and the tensile strength, shore A hardness of NBR3445vulcanizate still increased linearly with the increase of carbon black content, however, the tear strength of NBR culcanizate increased exponentially. The mathematical formula y(Ψ)=A+BΨ or y(T)=A+BeKT could fit well. When the content of carbon black or silica was40phr, the tensile strength, shore A hardness,tear strength of NBR vulcanizate reduced exponentially with the increase of test temperature.When the kind or content of filler changed,the index A,B,K. also could change.This section mainly studied the effect of different vulcanization systems on the Mechanical Properties of NBR and the tensile fracture of NBR at different temperatures. The experimental results showed that the tensile strength, tear strength of different vulcanization systems of NBR vulcanizates were reduced gradually along with the temperature increasing, and the trend of decreasing was weakened. The shore A hardness of different vulcanization systems of NBR vulcanizate firstly reduced and then remained unchanged with the increase of test temperature. In four kind of curing systems, DCP vulcanization vulcanized rubber had the best tensile strength and the worst tear strength; When test temperature was lower than75℃, the tear strength of CV vulcanization vulcanized rubber was the best and that of SEV vulcanization vulcanized rubber was slightly worse. The SEM photoes of NBR tensile fracture surface at room temperature and high temperature had a big difference.The earbon black particles were coated in rubber matrix on the tensile fracture surface at room temperature,and the fracture surface was relatively smooth. The most carbon black particles were half-naked or naked in rubber matrix on the tensile fracture surface at high temperature,and the fracture surface was relatively rough.