Oligomer, method for preparing oligomer, and method for preparing cured product of oligomer

A method for preparing an oligomer, comprising the following steps:

• (a) adding a bio-based diene compound and a phenolic compound in a Lewis acid catalyst, raising temperature to 80-150° C., and stirring to allow them to react, washing with water after synthesis and neutralizing and purifying to obtain a phenolic reactant;
• (b) mixing the phenolic reactant obtained in step (a) with 2,6-xylenol in a co-solvent of methanol and water containing a copper catalyst and an amine catalyst, and carrying out oxidative polymerization in an oxygen environment and at a temperature of 0-70° C. to obtain a bisphenol polyphenylene ether oligomer;
• and
• (c) allowing the bisphenol polyphenylene ether oligomer obtained in step (b) to react with methacrylic anhydride or vinyl benzyl halide at a temperature of 45-100° C. under the catalysis of an alkali catalyst to obtain the oligomer.