2-Propenoic acid, 2-methyl-, polymer with ethenylbenzene, 2-ethylhexyl 2-methyl-2-propenoate, ethyl 2-methyl-2-propenoate, 2-hydroxyethyl 2-methyl-2-propenoate and methyl 2-methyl-2-propenoate, 2,2'-(1,2-diazenediyl)bis[2-methylpropanenitrile]-initiated