Crosslink density Crosslinking 14 Curing 10 Rubber 10 Vulcanization 10 Elasticity 6 Mathematical models 6 Stresses 6 Swelling 6 Conformational tube model 4 Conformations 4 Density (specific gravity) 4 Mechanical variables measurement 4 Molecular structure 4 Positron annihilation spectroscopy 4 Rheometers 4 Strain 4 Strain measurement 4 Structure (composition) 4 Styrene butadiene rubber 4 Sulfur 4 Tube model 4 1,3 butadiene 2 Amines 2 Brittleness 2 Butadiene 2 Chain extenders 2 Chain packing 2 Characterization 2 Chemical structure 2