CARBON-FIBER MODIFIED COMPOSITES OF TETRAFLUOROETHYLENE-ETHYLENE COPOLYMERS

Composites based on tetrafluoroethylene-ethylene copolymers with graphitized polyacrylonitrile fibers were developed. The effect of the fiber length and concentration on the properties of the compositions was studied. Thermoactivation of the fibers was carried out and its influence on the properties of the tetrafluoroethylene-ethylene compositions was studied. Graphitized fibers possessing the highest content of oxygen-containing functional groups thermoacttivated at 1073 K for 30 min exerted the highest reinforcing effect(similar to 40%). The relation between fibers finished with gamma-aminopropyltriethoxysilane and the properties of the compositions obtained was also studied. A synergetic effect on the compositions mechanical and thermal properties was observed for the modified carbon fibers, whereas the other properties remained almost the same. The additional reinforcement of the carbon compositions modified with fiber monocrystals of alkali titanates in concentrations from 0.5 to 5.0 wt% strengthens the tetrafluoroethylene-ethylene polymer matrix by increasing the dynamic modulus, hardness, and thermoresistance of the composites.