The invention discloses a high-
flame-retardancy
modacrylic composite
fiber and a preparation method thereof, and belongs to the technical field of
high polymer materials. The composite
fiber is prepared from the following components in parts by weight: 80-95 parts of
modacrylic, 5-15 parts of a modified DOPO (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-
oxide) derivative, 3-10 parts of a
phosphate layered double
hydroxide, 1-5 parts of a dispersing agent, 0.5-3 parts of a heat stabilizer, 2-8 parts of a
plasticizer and 300-500 parts of a
solvent. The preparation method comprises the following steps: synthesizing a modified DOPO derivative; preparing a phosphating layered double
hydroxide; preparing a
spinning solution and performing electrostatic
spinning; and carrying out heat treatment on the nascent
fiber felt, so that the DOPO derivative is grafted to the
modacrylic molecular chain through a
covalent bond. Permanent fixation of
flame-retardant components is achieved through chemical
grafting, the problem of migration of the
flame-retardant components is solved, and by means of the gas-
solid phase synergistic flame-retardant effect of the DOPO derivative and the phosphating layered double
hydroxide, the fiber has high flame retardance, excellent durability and good mechanical performance.