Recycling of fiber-reinforced composite material using electromagnetic radiation

1. A method for removing fibers from a fiber-reinforced composite material via electromagnetic radiation to prepare for a recycling process, the method comprising:

placing the fiber-reinforced composite material within a microwave chamber, the fiber-reinforced composite material comprising glass fibers within a polymer matrix;

causing the glass fibers to be expelled from the polymer matrix by exposing the fiber-reinforced composite material to variable-frequency electromagnetic radiation; and

separating the glass fibers from the polymer matrix to render the polymer matrix suitable for the recycling process.

2. The method of claim 1 , further comprising:

prior to exposing the fiber-reinforced composite material to the variable-frequency electromagnetic radiation, processing the fiber-reinforced composite material to increase a surface area of the fiber-reinforced composite material.

3. The method of claim 1 , further comprising:

prior to exposing the fiber-reinforced composite material to the variable-frequency electromagnetic radiation, covering the fiber-reinforced composite material with an electromagnetic-radiation-permeable cover to contain the glass fibers expelled from the polymer matrix.

4. The method of claim 1 , wherein the fiber-reinforced composite material is exposed to the variable-frequency electromagnetic radiation to increase a temperature of the fiber-reinforced composite material at a predetermined ramp rate until the fiber-reinforced composite material reaches a predetermined target temperature and held at the predetermined target temperature for a predetermined hold time.

5. The method of claim 4 , wherein the predetermined ramp rate is 5° C. per minute and the predetermined hold time is at least 7 minutes.

6. The method of claim 1 , wherein the variable-frequency electromagnetic radiation is within a frequency range of 27 MHz to 300 GHz.

7. The method of claim 1 , further comprising:

after exposing the fiber-reinforced composite material to the variable-frequency electromagnetic radiation, reorientating the fiber-reinforced composite material within the microwave chamber; and

after reorientating the fiber-reinforced composite material, exposing the fiber-reinforced composite material to further variable-frequency electromagnetic radiation.

8. A method for removing fibers from a fiber-reinforced composite material via electromagnetic radiation to prepare for a recycling process, the method comprising:

placing the fiber-reinforced composite material within a microwave chamber, the fiber-reinforced composite material comprising reinforcing fibers within a polymer matrix;

causing the reinforcing fibers to be expelled from the polymer matrix by exposing the fiber-reinforced composite material to variable-frequency electromagnetic radiation to increase a temperature of the fiber-reinforced composite material at a predetermined ramp rate until the fiber-reinforced composite material reaches a predetermined target temperature and held at the predetermined target temperature for a predetermined hold time; and

separating the reinforcing fibers from the polymer matrix to render the polymer matrix suitable for the recycling process.

9. The method of claim 8 , wherein the reinforcing fibers are a material selected from a set consisting of glass fibers, carbon fibers, metallic fibers, nylon fibers, organic fibers, silicon oxide fibers, or poly-para-phenylene terephthalamide fibers.

10. The method of claim 8 , wherein the polymer matrix comprises diallyl phthalate.

11. The method of claim 8 , wherein the fiber-reinforced composite material is exposed to the variable-frequency electromagnetic radiation by passing it through the microwave chamber on a conveyor belt for a predetermined number of cycles.

12. The method of claim 8 , wherein the predetermined target temperature is within a range from 170° C. to 180° C.

13. The method of claim 8 , wherein the predetermined ramp rate is at least 5° C. per minute.

14. The method of claim 8 , wherein the variable-frequency electromagnetic radiation is in a frequency range of 5.85 Ghz to 6.65 GHz.

15. A method for removing fibers from a fiber-reinforced composite material via electromagnetic radiation, the method comprising:

placing the fiber-reinforced composite material within a microwave chamber, the fiber-reinforced composite material comprising reinforcing fibers within a polymer matrix;

causing the reinforcing fibers to be expelled from the polymer matrix by exposing the fiber-reinforced composite material to variable-frequency electromagnetic radiation to increase a temperature of the fiber-reinforced composite material at a predetermined ramp rate until the fiber-reinforced composite material reaches a predetermined target temperature and held at the predetermined target temperature for a predetermined hold time; and

collecting the reinforcing fibers expelled from the polymer matrix.

16. The method of claim 15 , wherein the reinforcing fibers are chopped-glass fiber fibers.

17. The method of claim 15 , wherein the reinforcing fibers are continuous fiber reinforcement fibers.

18. The method of claim 15 , wherein the variable-frequency electromagnetic radiation is in a frequency range of 10 MHz to 300 GHz.

19. The method of claim 15 , wherein the reinforcing fibers are collected from a sacrificial, microwave-permeable coating of the microwave chamber.

20. The method of claim 15 , wherein the fiber-reinforced composite material is exposed to the variable-frequency electromagnetic radiation for a time within a range of 5 minutes to 2 hours.