Hydrogenated nitrile rubber (HNBR) is mainly used in applications that require high and low temperature dynamic properties and good aging resistance, after swelling in oil and fluid After swelling in oils and fluids, HNBR is mainly used in applications requiring high dynamic properties at high and low temperatures and good aging resistance. Typical applications requiring these properties are timing belts, high pressure hoses and paper rolls. The rubber products used are subjected to extremely demanding dynamic conditions and are often subjected to shocks over a wide range of temperatures and frequencies. Conventional tests used to characterize the dynamic properties of materials are generally conducted at room temperature.
While these tests can characterize unfilled materials well, measurements at ambient temperatures do not reflect the effects of temperature on filler-monomer interaction. filler and filler-polymer interactions and their effect on material properties at very high temperatures. For polymers designed specifically for high temperature applications, an understanding of the effect of temperature on the technical properties of the material is necessary for proper compound optimization.
In this paper, the effect of temperature on the technical properties of filled rubbers is investigated, focusing on the type of filler, its dosage, and the interaction of the filler with HNBR and hydrogenated carboxylated nitrile butadiene rubber (HXNBR) polymers.
For this purpose, this paper compares reinforcing (N330) and non-reinforcing (N990) carbon blacks with silica (VulcasilN). The surface of silica can be modified both passively (filler surface hydrophobic) and actively (filler surface hydrophobic and bonded to polymer). An increasing number of compounds also use monomeric fillers, such as zinc diacrylate (ZAD), which can be polymerized in situ during vulcanization to improve material properties. These new "fillers" and their interaction with the polymer matrix have not yet been studied in terms of temperature and frequency dependent properties. The new "fillers" and their interaction with the polymer matrix have not been studied in terms of temperature and frequency dependent properties.
Based on the mechanical and dynamic mechanical properties of vulcanized and unvulcanized HNBR compounds, various fillers (carbon black, silica and ZDA) were analyzed for filling. and ZDA) filled standard HNBR and HXNBR rubbers were analyzed with respect to the temperature dependence of the reinforcing properties.
The decrease in modulus with increasing temperature for all unvulcanized rubbers (except for the silica-filled system) is a consequence of the temperature dependence of the viscosity of the polymer matrix. The type and amount of filler in the binder only determines the degree of reinforcement and has no effect on the temperature dependent decrease in binder modulus.
For silica-filled adhesives, the coalescence of the silica particles determines the temperature-dependent behavior. If the silica surface is treated with silica alkane treatment to achieve hydrophobicity, the coalescence of silica particles is inhibited. At large deformation amplitudes, the reinforcement of all carbon black and silica-filled compounds can be described as hydrodynamic reinforcement only.
If ZDA is used as a filler, no reinforcing effect is observed in the unvulcanized rubber compounds because ZDA is not yet polymerized and acts only as a low relative molecular mass plasticizer. The ZDA-containing compounds had low viscosities at all strains, indicating good processing properties.
Comparison of the dynamic mechanical properties and stress-on-strain properties of the vulcanized rubber showed that the ZDA-filled HXNBR rubber compound had the greatest complementary Strength and maximum ultimate mechanical properties (stress and elongation at break) decreased with increasing temperature for all the binders. The strong interaction between the filler surface and the polymer matrix enhances the effect of temperature on reinforcing properties. Although ionic interactions between ZDA and HXNBR carboxyl groups maximized the fracture stress, these ionic interactions had no effect on the temperature dependence of the fracture stress. This suggests that mechanically stable ionic interactions between ZDA and the functionalized polymer matrix (HXNBR) are a prerequisite for excellent mechanical and dynamic mechanical properties of the rubber material with low hysteresis loss under dynamic deformation conditions.
