Table 5. Vulcanizate Structure of Various Vulcanizates

Crosslink density (10−4 mol/g)	EV-S8	EV-S10	EV-S12	SEV-S8	SEV-S10	SEV-S12
TCDa	1.12	1.16	1.22	1.33	1.40	1.48
CCDb	0.57	0.54	0.53	0.68	0.68	0.67
FRIc (= a−b)	0.55	0.62	0.69	0.65	0.72	0.81

Total crosslink density;
Chemical crosslink density by vulcanization reactions between vulcanization agents and matrix rubber;
Crosslink density by filler-rubber interactions (FRI) in a silica-silane system (silica-rubber coupling).