Anionic Polymerization

A great number of our polymer products have been made via anionic polymerization - a very precise mechanism, which allows us to make polymers with a large diversity and high quality. Here are some examples or categories of polymers that we have made using this mechanism: ethoxylates, polylactide (PLA), polycaprolactone (PCL), PCLA, PLGA, PEG and derivatives, polycyanoacrylate, polybutadiene, polystyrene, block copolymers with different combination, etc. We have been very excited in using this powerful method to build up our product portfolio or generate specialty polymers. Here are two typical cases that we had worked on, showing the uniqueness of anionic polymerization process.

Case 1: Polybutadiene or Poly(butadiene-b-ethylene oxide)
The anionic polymerization of butadiene with termination agent forms a hydroxyl-ended polybutadiene, from which a block copolymer of PBD-PEG-OH or HO-PEG-PBD-PEG-OH can be generated. On the other hand, the hydroxyl end group opens a door to make many different end functional groups, e.g., carboxyl, acrylates, amine, etc. Not only can the molecular weight be precisely controlled but also the PDI appears very small, varying between 1.06-1.10.

Case 2: Polystyrene or Poly(styrene-b-ethylene oxide)
Using styrene instead of butadiene in the same procedure as shown in Case 1, PS-OH, HO-PS-OH, PS-PEG-OH, and HO-PEG-PS-PEG-OH can be made, and likewise which may lead to other functional-ended derivatives.

At this point, one may naturally think of a block polymer of PS-PBD or PBD-PS-PBD can be synthesized in a simpler manner without intermediate termination.