This paper deals with the short branch effect in alpha -olefin copolymers o
n radius of gyration R-g and intrinsic viscosity [eta] in trichlorobenzene
at 135 degreesC. A wide range of structurally uniform copolymers of ethylen
e with propylene, 1-butene, 1-hexene, and 1-octene were analyzed by size ex
clusion chromatography with on-line refractive index, low-angle and multian
gle light-scattering and viscometry detectors. Variation of refractive inde
x increment with composition was determined, and corrections for finite con
centration were applied. Both R-g and [eta] are accurately described by pow
er laws R-g = KsMalpha s and [eta] = KvMalpha v. The coefficients K-s and K
-v vary with comonomer type and amount, but the same exponents, alpha (s) =
0.58 and alpha (v) = 0.695, apply within the measurement uncertainty to al
l polymers studied. The ratios g(SCB) = R-g(2)/(R-g(2))(PE) and g'(SCB) = [
eta]/([eta])(PE) vary linearly with comonomer weight fraction, with slopes
that depend on the comonomer type. Various explanations for the observation
s are considered.