Poly(Boc-acryloyl hydrazide): The importance of temperature and RAFT agent degradation on its preparation

Poly(acryloyl hydrazide) is a versatile polymer scaffold readily functionalised through post-polymerisation modification with aldehydes to yield polymers for biological applications. However, its polymerisation is affected by nucleophilic degradation of the RAFT agent that leads to early termination, an issue often overlooked in the polymerisation of primary acrylamides. Here we report the effect of temperature on the RAFT polymerisation of N’-(tert-butoxycarbonyl)acryloyl hydrazide (1) and demonstrate that by carefully selecting this polymerisation temperature, a balance between rate of polymerisation and rate of degradation of the RAFT agent can be achieved. This way a greater control over the polymerisation process is achieved, allowing the synthesis of Boc-protected poly(acryloyl hydrazide) with higher degrees of polymerisation than those achieved previously, while still maintaining low dispersities. We believe our results should be of importance to those working on the RAFT polymerization of primary and secondary (meth)acrylamides and monomers with nucleophilic moieties.