Researchers at Colorado State University have developed a novel route to produce macromonomers via a group transfer polymerization. This method allows brush polymers to be made quickly, control un-desirable side reactions, and produce high yields of the desired brush polymer product, with high selectivity of the grafting process. The method is particularly useful for the synthesis of methacrylate, acrylate, and acrylamide based macromonomers.
Brush polymers (BPs) are polymers which feature polymeric side chains grafted to a linear backbone. BPs have found widespread use toward applications such as emulsifiers, nano-carriers for drug delivery, stimuli-responsive coatings, lithographic patterning, and photonics. To access BPs structures, grafting-from, grafting-to, or grafting-through strategies have been used. The grafting-to method typically uses a monotelechelic polymer chain that can be later “clicked” on to a functionalized linear backbone. Similarly, the grafting-from method allows for the polymer to be grown directly from an initiating site off a linear backbone. Unfortunately, both of these methods offer poor control over back bone grafting density. Alternatively, the grafting through approach involves the polymerization of macromonomers and results in a controlled and quantitative grafting density.
The method presented here provides an efficient process for preparing brush polymers. In general, the process involves three distinct reaction steps utilizing two separate catalysts. In the first step, the initiating compound, typically norbornene, is contacted with a silane in the presence of a catalyst, thereby forming a silated intermediate. This silated intermediate is then contacted with a monomer in the presence of a catalyst via Group Transfer Polymerization (GTP). The resulting compound from the GTP step is then contacted with a ring opening metathesis polymerization (ROMP) catalyst to prepare the brush polymer. Surprisingly, the brush polymers obtained from the above process are accessed in an efficient and rapid GTP methodology as compared to prior methods.
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Garret Miyake
Ryan Pearson
Matthew Ryan
Aly Hoeher
Aly.Hoeher@colostate.edu
970-491-7100