Method for preparing heavy-duty tire with natural rubber modified by graphene/carbon blacks varying in particle size synergized with vulcanization system

A method for preparing a heavy-duty tire with a natural rubber (NR) modified by graphene/carbon blacks varying in particle size synergized with a vulcanization system, comprising:

• (1) sequentially adding water, a disodium methylene bisnaphthalene sulphonate, a sodium alkylnaphthalene sulfonate, KOH, and a casein into a mixer under stirring for dissolution;
• and after complete dissolution, sequentially adding a quartz sand and carbon blacks varying in particle size into the mixer followed by stirring at a first preset speed for a first preset time to obtain a dispersion of surface-treated carbon blacks varying in particle size;
• wherein a weight ratio of the water to the disodium methylene bisnaphthalene sulphonate to the sodium alkylnaphthalene sulfonate to the KOH to the casein to the quartz sand to the carbon blacks is 720:1:0.5:1.5:3:150:80;
• the carbon blacks comprise N330 carbon black, N110 carbon black, N660 carbon black, and N765 carbon black;
• and a weight ratio of the N330 carbon black to the N110 carbon black to the N660 carbon black to the N765 carbon black is 3:0-1:0-1:0-1, wherein the N110 carbon black, the N660 carbon black, and the N765 carbon black are not simultaneously 0;
• (2) subjecting a graphene oxide (GO) aqueous dispersion to dilution with deionized water to obtain a diluted GO aqueous dispersion with a first preset concentration;
• and adding the dispersion of surface-treated carbon blacks varying in particle size to the diluted GO aqueous dispersion followed by ultrasonication at a preset power for a second preset time to obtain a GO/carbon blacks varying in particle size aqueous dispersion;
• (3) adding deionized water to a latex of a NR for dispersion to obtain an NR dispersion with a second preset concentration;
• adding the GO/carbon blacks varying in particle size aqueous dispersion to the NR dispersion followed by mechanical stirring at a second preset speed for a third preset time to obtain a mixed emulsion;
• adding a flocculant to the mixed emulsion for flocculation to obtain a crude rubber;
• and subjecting the crude rubber to water washing, water removal, and drying to obtain a GO/carbon blacks varying in particle size modified NR masterbatch;
• (4) subjecting the GO/carbon blacks varying in particle size modified NR masterbatch to internal mixing at a first preset temperature in an internal mixer;
• sequentially adding an anti-aging agent, an antioxidant, and a vulcanization accelerator to the GO/carbon blacks varying in particle size modified NR masterbatch followed by the internal mixing, and adding an activator and a softener to the GO/carbon blacks varying in particle size modified NR masterbatch followed by the internal mixing for dispersion to obtain a first rubber compound;
• and
• cooling the first rubber compound to room temperature followed by open milling on two rolls of an open mill at a second preset temperature for a fourth preset time, and adding a vulcanizing agent followed by mixing and mill run until there are no bubbles in the first rubber compound;
• and allowing the first rubber compound to stand for a fifth preset time, so as to obtain a second rubber compound;
• wherein the second rubber compound is a graphene/carbon blacks varying in particle size synergistically modified NR compound;
• a weight ratio of the NR in the second rubber compound to the anti-aging agent to the antioxidant to the vulcanization accelerator to the activator to the softener to the vulcanizing agent is 100:1:1:1:5:2:3;
• and the vulcanization accelerator is N-cyclohexylbenzothiazole-2-sulphenamide, and the vulcanizing agent is sulfur;
• and
• (5) placing the second rubber compound into a mold followed by vulcanization under a preset pressure at a third preset temperature for a sixth preset time, so as to obtain the heavy-duty tire.