Fig. 1. Influence of grinding sphere density on small hydrocarbon production. (A) Propene flow during milling of 2 g model PP at 30 Hz with 5 Al2O3, ZrO2, Fe, and WC grinding spheres (10 mm diameter). The inset shows a magnification of the propene flow. (B) Cumulative C1–3 hydrocarbon yields obtained after 1 h of milling 2 g model PP at 30 Hz with 5 Al2O3, ZrO2, Fe, and WC grinding spheres (10 mm diameter). The inset shows a magnification of the cumulative yield. (C) 
as a measure for chain cleavage calculated from experimental data viaeqn (15) plotted against grinding sphere density ρ and fit (gray line) using the modified Zhurkov equation (eqn (12)).
