HNBR Raw

The vulcanization system mainly adopts peroxide vulcanization, which has good heat resistance and good compression permanent deformation; it is generally not applicable to sulfur vulcanization system, mainly because of low bonding energy of polysulfide bond and poor heat resistance.

Note: A small amount of vulcanization can give HNBR Raw some dynamic performance and strength improvement (5/0.5), and also bring some sacrifice of heat resistance and slight increase of permanent deformation in compression.

The dosage of vulcanizing agent has a great influence on the strength of rubber, if the dosage is too low, the crosslinking is not ripe and the strength is low; if the dosage is too high, the crosslinking density is too large and the tensile strength is easy to produce stress concentration, resulting in a decrease in strength.

However, in the HNBR system, DCP will react with the silane coupling agent containing sulfhydryl group and prevent the vulcanization process, so the silane coupling agent containing sulfur should be avoided when choosing silane coupling agent.

ZDMA, as an excellent organic reinforcing agent, is commonly used in HNBR reinforcing system. The strength of HNBR reinforced by ZDMA can reach more than 40Mpa (ZSC alloy is ZDMA used with HNBR), but the tensile permanent deformation is very large. ZDMA is often used with traditional fillers, which can improve the strength of the rubber on the basis of ensuring the pressure change performance of HNBR.

Generally speaking, the aging resistance of hydrogenated nitrile is very good, so the antioxidant system is not necessary for HNBR; moreover, the sulfur antioxidant will cause the cross-linking degree of HNBR Raw to decrease, the strength to deteriorate and the elongation to increase.

4010NA will seriously affect the cross-linking reaction of DCP and reduce the cross-linking density; MBZ (accelerator MB has anti-aging effect, its zinc salt also has anti-aging effect, but it will lead to the decomposition of peroxide) and antioxidant 445 have less effect on peroxide cross-linking, high cross-linking density, small permanent deformation in compression, and good antioxidant performance; HNBR without antioxidant still has the antioxidant performance of the whole system. HNBR without antioxidant, the antioxidant performance of the whole system is still excellent, and MBZ and 445 have less influence on the degree of vulcanization.

TOTM, TP-50 are effective plasticizing systems for HNBR Raw, which can reduce the mensuration viscosity and hardness of the rubber, but will reduce the vulcanization speed of the rubber, which can improve the strength and elongation of the rubber.

Liquid nitrile rubber plasticized HNBR can reduce the rubber's meniscus and improve the physical properties and heat resistance of the rubber without reducing the vulcanization speed of the rubber, and will participate in the co-crosslinking reaction (HTBR: carboxylated liquid nitrile rubber); some research shows that HTBR plasticized HNBR, the strength of the vulcanized rubber can reach 40MPa.