Rotary member and method for manufacturing same

1. A rotary member including an inner circumference and an outer circumference rotatable along a circumferential direction of the inner circumference and the outer circumference, the rotary member comprising:

carbon fibers wound in the circumferential direction;

a matrix resin in which the carbon fibers are embedded;

a structure which includes a plurality of carbon nanotubes having a bent shape with a bent portion, forms a network structure including a contact portion where the carbon nanotubes are in direct contact with each other, and is provided on surfaces of the carbon fibers; and

a first sizing agent which functions as an aqueous cross-linking agent, the first sizing agent cross-links and fixes the carbon nanotubes which are in direct contact with each other around the contact portion,

wherein, in the structure, a gap surrounded by the plurality of carbon nanotubes is formed, and the first sizing agent does not fill up the gap.

2. The rotary member according to claim 1 ,

wherein the structure has a thickness in a range of 50 nm to 200 nm.

3. The rotary member according to claim 1 ,

wherein a fiber volume content of the carbon fibers is less than 75%.

4. The rotary member according to claim 1 ,

wherein a first sizing agent includes a carbodiimide-derived structure.

5. A method for manufacturing a rotary member including an inner circumference and an outer circumference rotatable along a circumferential direction of the inner circumference and the outer circumference, comprising:

a structure forming process of immersing carbon fibers in a dispersion in which carbon nanotubes having a bent shape with a bent portion are dispersed and to which ultrasonic vibration is applied to adhere the carbon nanotubes to the carbon fibers, thereby forming a structure having a network structure including a contact portion where the carbon nanotubes are in direct contact with each other on surfaces of the carbon fibers;

a first sizing treatment process of causing the carbon fibers to come into contact with a first sizing treatment solution, after the structure forming process, to apply a first sizing agent which functions as an aqueous cross-linking agent, the first sizing agent cross-links and fixes the carbon nanotubes which are in direct contact with each other; and

a molding process of applying a matrix resin to the carbon fibers in which the structure is formed, winding the carbon fibers applied with the matrix resin around a mandrel, curing the matrix resin, and pulling out the mandrel, after the first sizing treatment process,

wherein, in the structure, a gap surrounded by the plurality of carbon nanotubes is formed, and the first sizing agent does not fill up the gap.

6. The method for manufacturing a rotary member according to claim 5 ,

wherein the first sizing treatment solution is a solution in which a carbodiimide compound having a carbodiimide group is dissolved.

7. The method for manufacturing a rotary member according to claim 6 ,

wherein in the first sizing treatment process, the first sizing agent is applied in a mass within a range of 0.6% to 1.1% with respect to a mass of the carbon fibers.

8. The method for manufacturing a rotary member according to claim 6 ,

wherein in the structure forming process, the structure is formed in a thickness within a range of 50 nm to 200 nm.

9. The method for manufacturing a rotary member according to claim 5 ,

wherein in the molding process, the carbon fibers applied with the matrix resin is wound around the mandrel so that a fiber volume content of the carbon fibers in the rotary member is less than 75%.