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Benzoxazineis a new kind of phenolic resin synthesized by Cope and Holly in the 1940s.Benzoxazine can be polymerized through ring-opening by thermal invitation without the need for harsh catalysts. Polybenzoxazines not only have excellent mechanical properties, good thermal stability, and outstanding dielectric properties as traditional thermoset resin but also have some special characteristics, including extensive sources of raw materials, molecular design flexibility, and near-zero shrinkage upon polymerization. Based on these features, polybenzoxazines are ideal materials for replacing traditional phenolic resin and epoxy resin in high-performance fields. However, as a kind of thermoset resin, polybenzoxazines have their shortcomings when used in high-performance fields; for example, a relatively high curing temperature is needed without catalysts, brittleness of cured products, and lower thermal properties. The main reason for the low thermal properties is the low cross-link density of cured products . Three methods are used to solve this problem: (1) Synthesizing new benzoxazine monomers using amines and phenols that contain special functional groups, for example, introducing cyano groups, allyl groups , and maleimide groups into the benzoxazine monomer.