Effect of modified graphene and microwave irradiation on the mechanical and thermal properties of P(S-co-MMA)/graphene nanocomposites

1. A method for forming a blend comprising graphene nanoparticles and a poly(styrene-co-methylmethacrylate), comprising:

modifying graphene with nitric acid to form graphene nanoparticles surface modified with one or more oxygen functionalities;

melt blending the poly(styrene-co-methylmethacrylate) and the modified graphene nanoparticles to obtain a nanocomposite; and

exposing the nanocomposite to microwave irradiation to form defects in the graphene nanoparticles,

wherein the poly(styrene-co-methylmethacrylate) includes a polystyrene to methyl methacrylate content ratio of 50-90/20-40 by weight.

2. The method of claim 1 , comprising further exposing the nanocomposite to microwave irradiation for 5 to 15 minutes.

3. The method of claim 1 , wherein the oxygen functionalities are selected from the group consisting of a carboxyl group, carbonyl group, epoxy group, and hydroxyl group, on a defects site or a side wall of graphene.

4. The method of claim 1 , wherein the poly(styrene-co-methylmethacrylate) and the modified graphene are bonded through a methacrylate portion of the poly(styrene-co-methylmethacrylate) to the graphene by addition across a C═C bond.

5. The method of claim 1 , wherein modifying the graphene comprises adding nitric acid to graphene to obtain a mixture, and refluxing the mixture at a temperature of from 100 to 140° C.

6. The method of claim 1 , wherein a weight/volume ratio of graphene to nitric acid is from 1-3 g/100-500 ml.

7. The method of claim 1 , wherein a content of the graphene nanoparticles is from 0.05 to 0.125 wt % based on 100 wt % of the poly(styrene-co-methylmethacrylate).

8. The method of claim 1 , wherein the modified graphene has a diffraction peak of 18.9±0.5° C. before the melt blending.

9. The method of claim 1 , further comprising compression molding the poly(styrene-co-methylmethacrylate)/modified graphene nanocomposites after the melt blending and before the exposing to microwave irradiation.

10. The method of claim 1 , wherein the nanocomposites are subjected to microwave irradiation at a frequency of from 2300 to 2600 MHz.

11. A method for forming a blend comprising graphene nanoparticles and a poly(styrene-co-methylmethacrylate), comprising:

modifying graphene with nitric acid to form graphene nanoparticles surface modified with one or more oxygen functionalities;

melt blending the poly(styrene-co-methylmethacrylate) and the modified graphene nanoparticles to obtain a nanocomposite, and

exposing the nanocomposite to microwave irradiation to form defects in the graphene nanoparticles,

wherein the nanocomposites are subjected to microwave irradiation at a power of from 900 to 1100 watts.

12. The method of claim 1 , comprising performing the microwave irradiation in cycles ranging from 40 to 80 seconds, wherein in between the cycles, the nanocomposites are cooled to room temperature for a time period ranging from 100 to 140 seconds.

13. The method of claim 11 , comprising further exposing the nanocomposite to microwave irradiation for 5 to 15 minutes.

14. The method of claim 11 , wherein the oxygen functionalities are selected from the group consisting of a carboxyl group, carbonyl group, epoxy group, and hydroxyl group, on a defects site or a side wall of graphene.

15. The method of claim 11 , wherein the poly(styrene-co-methylmethacrylate) and the modified graphene are bonded through a methacrylate portion of the poly(styrene-co-methylmethacrylate) to the graphene by addition across a C═C bond.

16. The method of claim 11 , wherein modifying the graphene comprises adding nitric acid to graphene to obtain a mixture, and refluxing the mixture at a temperature of from 100 to 140° C.

17. The method of claim 11 , wherein a weight/volume ratio of graphene to nitric acid is from 1-3 g/100-500 ml.

18. The method of claim 11 , wherein a content of the graphene nanoparticles is from 0.05 to 0.125 wt % based on 100 wt % of the poly(styrene-co-methylmethacrylate).

19. The method of claim 11 , further comprising compression molding the poly(styrene-co-methylmethacrylate)/modified graphene nanocomposites after the melt blending and before the exposing to microwave irradiation.

20. The method of claim 11 , comprising performing the microwave irradiation in cycles ranging from 40 to 80 seconds, wherein in between the cycles, the nanocomposites are cooled to room temperature for a time period ranging from 100 to 140 seconds.