The solution property of polyethylene grafted maleic anhydride in extremely dilute and dilute solutions is studied by the method of viscosity at high temperatures.A very sharp crossover is observed in the variation of the reduced viscosity.ηsp/C as a function of the concentration for polyethylene grafted maleic anhydride.This crossover is correlated with the critical concentraion of the polymer C** in which the macromolecular coils start their contacts.For extremely dilute solutions (CC**)ηsp/C changes lineary with concentration in a greater slope than that for dilute solutions (C>C**)

This shows the different morphologies and interactions of macromolecular coils in the two regions.The reduced viscosity also increases when the grafted rate and the temperature increase

but C** inclines to lowr concentration with the increase of temperature.