Flame-retardant aromatic polyoxadiazole and preparation method thereof

Abstract

The invention discloses flame-retardant aromatic polyoxadiazole and a preparation method thereof. The preparation method comprises the following steps: 1) reacting phenylphosphonic dichloride with 4 '-hydroxybiphenyl-4-carboxylic acid to prepare a phosphorus-containing dibasic acid monomer, and taking the phosphorus-containing dibasic acid monomer as a third monomer to participate in copolycondensation in the step 2); 2) taking fuming sulfuric acid as a solvent and a dehydrating agent, taking benzoic acid as a chain terminator, and performing polycondensation and cyclization reaction on hydrazine sulfate, terephthalic acid and a phosphorus-containing dibasic acid monomer to prepare a polymer spinning solution; 3) preparing a flame-retardant aromatic polyoxadiazole fiber by wet spinning; the phosphorus-containing dibasic acid monomer has the following structure: by introducing a phosphorus-based flame-retardant element into a polymer molecular chain, the in-situ synergistic interactionof the phosphorus-nitrogen-based flame-retardant element can be exerted, the flame retardancy of polyoxadiazole is improved, and the flame-retardant aromatic polyoxadiazole prepared by the method hasgood spinnability, and can be prepared into high-temperature-resistant fibers and film materials, and then can be used in the fields of honeycomb structure materials, electric insulation materials orcarbon precursors and the like.

Description

technical field [0001] The invention belongs to the technical field of flame-retardant polymer materials, and in particular relates to a flame-retardant aromatic polyoxadiazole and a preparation method thereof. Background technique [0002] Aromatic polyoxadiazole (POD) is a high-performance polymer with outstanding high-temperature stability containing benzene rings and oxadiazole rings in the molecular chain. Like other aromatic heterocyclic polymers, POD has excellent fiber-forming properties. It can be made into high temperature resistant fiber and film materials, and then used in the fields of honeycomb structure materials, electrical insulation materials or carbon precursors. [0003] POD has excellent thermal stability, and its thermal decomposition temperature reaches above 500°C, but its limiting oxygen index (LOI) is only 25%, and it is still flammable in air. Therefore, in order to meet the corresponding use requirements, it is necessary to further improve the fl...

AI Technical Summary

Problems solved by technology

Although halogen-based brominated flame retardants have good flame-retardant properties, they will release toxic gaseous hydrogen halides during combustion, causing environmental pollution; in contrast, phosphorus and nitrogen-based flame retardants are not easy to release during combustion Corrosive gas, and has good smoke suppression performance, has more application potential in the preparation of flame retardant polymers

In the prior art, there are few reports about the preparation of phosphorus-containing polyoxadiazoles by copolymerization

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