Development and synthesis scale-up of template monomers for AB alternating polyacrylamides

This thesis presents the development of a scalable synthesis route for AB-alternating polyacrylamides via cyclopolymerization of divinyl monomers derived from salicylic acid. The initially used monomer, 2-acrylamidoethyl 2-(acryloyloxy)-5-nitrobenzoate, exhibited severe limitations, including low polymerization conversions, poor solubility in necessary solvent systems, and radical quenching effects arising from its nitro substituent, ultimately resulting in compromised sequence fidelity.
To address these issues, a new series of divinyl monomers based on alternative salicylic acid derivatives was designed and synthesized. Dichloro- and dibromo- substituted monomers respectively demonstrated superior chemical stability, higher isolated yields, and minimized side reactions compared to both NODV and the previously published trifluoromethyl-substituted monomer. Free-radical polymerization of the dichloro - and dibromo- substituted monomers in 1,4- dioxane achieved conversions above 90 % within two hours, with balanced incorporation of acrylate and acrylamide units, no evidence of ester cleavage, and absence of residual vinyl groups, indicating precise cyclopolymer formation. Aminolysis of these cyclopolymers yielded the desired AB-alternating polyacrylamides, verified through a combination of 1H-NMR, MALDI-TOFMS, differential scanning calorimetry (DSC), and polarized optical microscopy. In particular, the characteristic mesomorphic transition behavior and the distinct mass spectral distributions confirmed the presence of strictly alternating sequences.
Overall, dichloro- and dibromo- substituted monomers proved to be the most promising candidates, offering reliable scalability, environmental advantages (absence of per- and polyfluoroalkyl substituents), and robust control over polymer architecture. These results establish a versatile and efficient synthetic platform for producing AB-alternating polyacrylamides, enabling their potential application as functional binder materials in energy storage systems and beyond.