Not Your Same Old Polymers – Same Monomers, New Polymers

By Bernd Gobelt, John Du

Controlled polymerization techniques provide the chemist with opportunities to customize polymers. The polymers made with these techniques are not only defined by their composition, molecular weight, and polydispersity index, but also by their synthesis method-demonstrated with two AB block copolymer dispersants prepared by GTP and ATRP.

Using these new polymerization techniques, novel polymeric additives for coatings and inks are being developed. Wetting and dispersing additives based on gradient copolymers and leveling additives based on polyacrylate extended polysiloxane block copolymers are two examples of new additive molecules based on controlled polymerization techniques.

Group transfer polymerization (GTP), atom transfer radical poly­merization (ATRP), nitroxyl mediated polymerization (NMP), and re­versible addition-fragmentation chain transfer process (RAFT) are con­trolled polymerization techniques currently practiced in the industry. These techniques are used to customize polymer structures such as block copolymers. Each of these polymerization techniques has bene­fits and limitations regarding reaction conditions and monomer range.

GTP is a pseudo-anionic polymerization process. The active polymer chain reacts with monomers via Michael’s addition. Other polymeriza­tion techniques are controlled radical polymerization techniques (CRP) that position a terminal radical group on the polymer chain as the propagating species. All these controlled radical polymerization tech­niques are differentiated by their mechanism and reaction conditions; these parameters determine the microstructure of the polymers.