Influence of the quantity of sewing comonomer on an exit and sewing degree of copolymer maleic anhydride, styrene and 1,4-di(4-isopropenyl­phenoxy)­­butane has been investigated­ and established that increasing the quantity of the latter the exit and  swelling degree  decrease. So, in the presence of 2 and 10 mol % 1,4-di(4-izopropenilfenoksi)butane the exit makes up accordingly 98 and 89.6 %, and degree of swelling ­– 680.0 and 260.2 %. It is revealed that Ra²⁺и Th⁴⁺ ions practically do not render negative influence on sorption processes of UО₂^{2 +}-ions with the hydrolyzed copolymer (obtained in the presence of 10 mol.  % of the sewing agent).