Hybrid Composites from Wheat Straw, Inorganic Filler, and Recycled Polypropylene: Morphology and Mechanical and Thermal Expansion Performance

Table 1

Surface energy parameters of PP and fillers.

	(mJ/m)	(mJ/m)	(mJ/m)	(mJ/m)	(mJ/m)
PP	28	24	0.02	1.1	0.3
SiO2	35.4	33.5	0.6	1.7	2.02
Fly ash	21.8	20.9	0.45	0.45	0.9
Heavy calcium carbonate	46.68	43.83	0.07	29	2.85
Straw	34.5	26	4.25	4.25	8.5