Second and third virial coefficients of low-molecular-weight polyisoprene in 1,4-dioxane

Light-scattering measurements were carried out on polyisoprene (PI) samples with weight-averaged molecular weights (Mws) ranging from 1.1 × 103 to 2.7 × 104 in 1,4-dioxane at and near the theta point, 35.3 °C, which is defined as the temperature at which the second virial coefficient A2 for sufficiently high Mw (larger than 1 × 104) vanishes. It was found that A2 at the theta point decreases with decreasing Mw for Mw