Synthesis of poly(dimethylsiloxane) oligomers with pendant amine groups via co‐equilibration anionic polymerization reactions

The present study describes a method of incorporating amine functional groups on poly(dimethylsiloxane) chains as pendant groups on silicon atoms. This method allows for independent control of the molecular weight and the amine content of the oligomer. The new molecular design was achieved by co‐equilibration of the cyclic tetramer octamethylcyclotetrasiloxane (D4) with a new cyclic siloxane monomer containing aliphatic amine substituents on the silicon atoms. The co‐equilibration of the two cyclic siloxanes was carried out in the presence of a silanolate catalyst, using the nonfunctionalized hexamethyldisiloxane as the end‐capper. The distribution of the molecular species at thermodynamic equilibrium and the efficiency of incorporation of siloxane units containing pendant amine functionalities into the poly(dimethylsiloxane) chains were investigated as a function of oligomer chemical composition and molecular weight.