Copolymer, preparation method therefor, vulcanized rubber and use thereof

A copolymer, wherein the copolymer is a block copolymer and the copolymer comprises a polyethylene segment and a butadiene rubber segment;

• based on the total weight of the copolymer, a weight ratio of the polyethylene chain segment to the butadiene rubber chain segment is within a range from 0.1:99.9 to 80:20;
• in the butadiene rubber chain segment, based on the total amount of the butadiene rubber chain segment, a content of the cis-1,4-structural unit is 90-98.5 mol %;
• a content of the trans-1,4-structural unit is 0.9-5.7 mol %, and a content of the 1,2-structural unit is 0.6-4.3 mol %;
• a continuous methylene sequence length in the copolymer is at least 165.

A method for preparing the copolymer comprising:

• (1) subjecting ethylene to a polymerization reaction in the presence of an organic solvent, a catalyst, and an aluminum-containing cocatalyst-1 to obtain a polyethylene product;
• wherein the temperature of the polymerization reaction is within a range of 20-70° C., the ethylene pressure is kept at 1-70 bar, and a time of the polymerization reaction is within a range of 1-80 min;
• (2) feeding 1,3-butadiene monomers into the polyethylene product and removing unreacted ethylene monomers;
• (3) adding an aluminum chloride-containing cocatalyst-2 into the polymerization system obtained in step (2) to initiate a copolymerization reaction between the 1,3-butadiene monomers and a polyethylene active chain segment in the polyethylene product to prepare the copolymer;
• wherein the catalyst is at least one selected from the group consisting of compounds represented by formula 1, formula 2, and formula 3;
• wherein X is chlorine or bromine;
• R1 is a substituent which is mono-substituted at the 2- or 4-site of the benzene ring, or the same or different substituents which are di-substituted at the 2-, 4-sites or 2-, 6-sites of the benzene ring, or the same or different substituents which are tri-substituted at the 2-, 4-, 6-sites of the benzene ring, wherein the substituent is —F, —CH3, —CH2CH3, —CH(CH3)2, —C(CH3)3, —C6H5, or —CH(C6H5)2;
• R3 is —CH3, —CH2CH3, —CH(CH3)2, —C(CH3)3, —C6H5, or —CH(C6H5)2 which is mono-substituted at the 6-site of the pyridine ring, or —CH3, —N(CH3)2, or —CF3 which is mono-substituted at the 4-site on the pyridine ring, or the same or different —CH3, —CH2CH3, —C6H5, —CH(C6H5)2, —N(CH3)2, or —CF3 which are di-substituted at the 4- and 6-sites of the pyridine ring;
• R5 is —CH3, —CH2CH3, —CH(CH3)2, —C(CH3)3, —C6H5, or —CH(C6H5)2 which is mono-substituted at the 4-site of the dihydro oxazole ring;
• R2, R4, and R6 are each independently H, or —Cl, —F, —CH3, —OCH3, —N(CH3)2, or —CF3 which are mono-substituted at the 4-site of the pyridine ring;
• R7 is H, —CH3, —CH2CH3, —CH(CH3)2, —C(CH3)3, —Cl, —C6H5, or —CH(C6H5)2.