Grafting poly(N,N-dimethylacrylamide) from cellulose nanocrystals by the macro-RAFT agent-assisted strategy

Polymer grafting is an efficient way to obtain functional cellulose nanocrystals. In this work, we used a “macro-RAFT (macromolecular reversible addition–fragmentation chain transfer) agent-assisted” strategy, which adds extra amount of amphiphilic macro-RAFT agent with low molecular weight to graft poly(N,N-dimethylacrylamide) (PDMA) from cellulose nanocrystals. Successful grafting was evidenced by different characterization methods, and a high weight ratio of grafted PDMA was obtained (77.6%). The grafting process was studied through the weight ratio of grafted PDMA, monomer conversion, and the molecular weight of free and grafted PDMA at different reaction time. As a result, we have suggested that there were three types of grafted polymer chains on cellulose nanocrystals in this reaction system and discussed their evolution during the grafting reaction. Finally, we summarized several key factors for successful grafting in this macro-RAFT agent-assisted strategy.