The invention belongs to the technical field of
flame-retardant materials, and particularly relates to a
phenylboronic acid-based P / N / B-containing
halogen-free
flame retardant, a preparation method thereof and application of the
phenylboronic acid-based P / N / B-containing
halogen-free
flame retardant in
epoxy resin. The preparation method comprises the following steps: by taking diphenyl hypophosphorous
chloride as a basis, preparing a flame-retardant intermediate through
nucleophilic substitution reaction between diphenyl hypophosphorous
chloride and an
aldehyde group-containing phenolic compound, then reacting a
phenylboronic acid structure with 3-amino-1, 2-
propylene glycol to obtain an amino group-containing phenylboronic acid compound, and finally reacting the phenylboronic acid compound with 3-amino-1, 2-
propylene glycol to obtain the amino group-containing phenylboronic acid compound. And finally, carrying out a
Schiff base reaction on the flame-retardant intermediate and an amino-containing phenylboronic acid compound to obtain the
halogen-free flame retardant containing
phosphorus,
nitrogen and
boron elements. The flame retardant provided by the invention can significantly improve the flame retardant property and
mechanical property of
epoxy resin. A flame-retardant
epoxy resin prepared based on the flame retardant; the influence on Tg of an epoxy resin cured product is small, the
smoke suppression and
char formation performance and the mechanical performance of the cured product can be remarkably improved, and meanwhile, the flame retardant has excellent flame retardant efficiency; the limit
oxygen index of the flame-retardant epoxy resin can reach 31%; the vertical
combustion grade is V-0 or above, and the carbon residue amount can reach 18% or above.