In-situ polymerization of monoethylenically unsaturated monomers with oligomeric or polymeric secondary amines

PROBLEM TO BE SOLVED: To provide a process for preparing a (co)oligomer or a (co)polymer. ; SOLUTION: The process for preparing a (co)oligomer or (co)polymer comprises forming a mixture containing a monoethylencally unsaturated monomer of formula (M): HR<SP>1</SP>C=CR<SP>2</SP>R<SP>3</SP>, an oxidizing agent, at least one polymer or oligomer of formula (I), and an optional radical initiator and heating the mixture at 0-220[deg.]C.