The elongation of star shaped polystyrenes in flowing solutions depends on
their number of branches and becomes lower when the number of branches incr
eases. The deformation of these polymers, ;expressed by the change of the c
ritical concentrations c** and c*, varies as (f/2)(2) for a constant differ
ence in shear rate (f is the number of branches). A simple theoretical mode
l correlates the increase of the resistance to the deformation or the rigid
ity of the star shaped polymers to the factor (f/2)(2).