Analysis of dynamic mechanical properties

After epoxidation of some double bonds in the NR molecular chain, the flexibility of the molecular chain decreases and the glass transition temperature (Tg) increases. Compound loss factor (tanδ) of NR and ENR without silica.

The tanδ at 0 ℃ of the rubber compound increases with the increase of the degree of epoxidation of ENR, which indicates that the dynamic hysteresis loss of the rubber compound becomes larger and the wet skid resistance is improved. The tanδ (characteristics of wet skid resistance) of ENR25 and ENR40 compounds at 0 ℃ is greater than that of NR compounds, and the tanδ (characteristic rolling resistance) of 60 ° C is smaller than NR, indicating that their wet skid resistance and rolling resistance are improved at the same time.

After white carbon black was added, ENR40 rubber had better anti-slip properties than NR rubber, and ENR25 had less rolling resistance than NR rubber. When the amount of white carbon black was 20 parts, ENR40 rubber had the same rolling resistance as NR rubber. When the degree of epoxidation of the white carbon rubber increases, the compression heat generation of the rubber compound increases. This is because the NR molecular chain contains a large number of double bonds, the molecular chain is flexible, and the internal friction between molecular chains is low. After the double bond on the rubber molecular chain is modified into an epoxy group, the flexibility of the molecular chain is reduced, and the friction internal friction between the molecular chains is increased. Therefore, the heat generation of the rubber increases with the degree of rubber epoxidation.