The paper examined the influence of the molecular weight distribution
types and the polydispersity index M(w)BAR/M(n)BAR of the values of th
e second virial coeffcient determined by light scattering, for ultrahi
gh molecular weight methyl methacrylatestyrene 50 : 50 random copolyme
rs. It was observed that for M(w)BAR/M(n)BAR<2 the polydispersity corr
ections for the second virial coefficient are not affecting the discus
sion of the excluded volume effect.