High-intrinsic-viscosity polyethylene naphthalate with branched structure and preparation method of high-intrinsic-viscosity polyethylene naphthalate

The invention discloses polyethylene naphthalate with a branched structure and high intrinsic viscosity number and a preparation method, and belongs to the technical field of material chemical engineering, the preparation method comprises the following steps: mixing 60-65 parts by mass of dimethyl 2, 6-naphthalate, 35-40 parts by mass of ethylene glycol, 0.1-2 parts by mass of tri/tetra-branched monomer, 0.01-0.5 part by mass of catalyst and 0.01-0.5 part by mass of antioxidant; and carrying out polymerization reaction, removing methanol, and then removing ethylene glycol. According to the invention, a certain amount of tri/tetra-branched monomer is added to form a branched chain structure on the main chain of the polymer, so that the viscosity of the polymer melt is reduced, which is beneficial to mass transfer and diffusion of a micromolecular byproduct ethylene glycol, further beneficial to forward proceeding of a polycondensation reaction and shortening the reaction time. And the branched structure reduce