Qf
Qg
¼ aez þ b (1)
Q ¼ Swollen weightðWsÞ Dried weightðWdÞ
Initial weightðWiÞð100=Formula weightÞ (2)
where subscripts f and g refers to filled and gum vulcanizates,
respectively. z is the ratio by weight of the filler to the
rubber hydrocarbon in the vulcanizates and a and b are
constants.