In recent years, because of the low price of polyester fiber, it has been widely used in the Russian textile industry, which reduces the amount of polyacrylonitrile fiber in textile products, and polyacrylonitrile fiber is more widely used in the production of carbon fibers.

Russian researchers studied some samples of acrylonitrile fibers made in Russia for the production of carbon fibers, and their filaments, different components of acrylonitrile copolymers, solvents used, and so on. X-ray photography, differential scanning calorimetry and pyrolysis were used. analytical method The results show that:

The composition of the copolymer does not affect the crystallization process of polyacrylonitrile fiber.

Different solvents have a significant effect on the size of polymer crystals during precipitation. Polyacrylonitrile fibers formed in organic solvents crystallized with 60-66% larger than that of polyacrylonitrile fibers formed in brine solution.

The analysis of the temperature data and the analysis of the heat capacity index showed that the polyacrylonitrile fiber polymerization chain formed by the brine solution had small heat capacity and rigid chain segment, and the rigidity of its non crystalline region exceeded that of the polyacrylonitrile fiber formed in the organic solvent. Polymerization chain 。

When the fibers were heated, the thermal gravimetric analysis showed that the mass loss of the three samples started at 287, 245 and 241 degrees respectively. At 292, 250 and 248, the mass loss is the fastest. At the temperature of 300, 257 and 259, the time of mass loss is the most. At 400 C, the total mass changes were three, 35.5%, 23.1% and 24.5% respectively.

Data analysis of pyrolysis gravimetric analysis shows that when the fibers are heated, the quality loss should be reduced. temperature In this way, the quality loss of polyacrylonitrile precursor can be reduced correspondingly.