The network and properties of the NR/SBR vulcanizate modified by electron beam irradiation

• NR/SBR vulcanizate as a typical tread material is modified by electron beam.
• Crosslinked structure of vulcanizate changes upon irradiation.
• The interaction between polymer and fillers is enhanced after irradiation.
• Rolling resistance and abrasion resistance are improved after irradiation.
• Electron beam has no obvious effect on wet skid resistance below 200 kGy.

A natural rubber/styrene butadiene rubber (NR/SBR) vulcanizate filled with carbon black was modified by high-energy electron beam (EB) irradiation in this work. The crosslinked structure was studied by a special chemical probe method. The influence of EB irradiation on mechanical properties, filler network, and dynamic properties including abrasion resistance, rolling resistance, and wet skid resistance was also investigated. The results revealed that the crosslink structure significantly changed after EB treatment, indicating that the amount of poly- and di-sulfide crosslinked bonds decreased and that of mono-sulfide bonds increased. The polymer–filler interaction was enhanced after EB irradiation. An EB dose of 600 kGy reduced the abrasion loss of the NR/SBR vulcanizate, and one of 300 kGy reduced the rolling resistance by 11.4%. Meanwhile, EB doses below 200 kGy had no obvious effect on the wet skid resistance. This EB-modified NR/SBR vulcanizate can be used to prepare high-performance tires with good abrasion resistance and low rolling resistance.