Foam parameters of pure PS and PS composites (100 °C, 13.8 MPa).

Samples	Average cell size (μm)	Cell density (cell per cm3)	Foam density (g cm−3)
Pure PS	6.16 ± 1.89	0.57 × 1010	0.31
PS/5% CNTs hybrid particle	2.79 ± 0.66	5.70 × 1010	0.37
PS/5% RGO hybrid particle	2.87 ± 0.73	5.54 × 1010	0.33