The synthesis and characterization of a processable polyrotaxane-based triblock copolymer via a "two steps" strategy

A polyrotaxane based triblock copolymer (PR copolymer) was synthesized successfully via a "two steps" strategy. In the first step, a PR macroinitiator was synthesized by end-capping of an adamantane stopper (AD stopper). In second step, the PR copolymer was prepared via atom transfer radical polymerization (ATRP) with a PR macroinitiator. Furthermore, it was found the cyclodextrin (CD) content in the PR macroinitiator was controllable in the first step, whereas the degree of polymerization (DP) of butylmethacrylate (BMA) also appeared tunable in the second step. Moreover, the PR copolymer was processed into a self-standing film via solution casting and a nonwoven mat with good morphology via electrospinning. The strain-stress test showed the film had a higher tensile strength than universal plastics, and pure PBMA and dynamic mechanical analyzer results inferred that the movement of the PR block may be also present in the PR copolymer and have some influence on the copolymer's mechanical properties. In conclusion, the controllability of CD content and polymer chain length provide enough room to modify its molecular structure so as to design and synthesize different PR copolymers with various properties and broaden their application field from solution and hydrogels to the solid state.