Cyclization of Linear Polymers

Problem 12.4 Suggest an ef cient route, via ATRP and CuAAC reaction, for the preparation of narrow disperse cyclic-polystyrene with an average of 24 styrene units in the ring. 

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Since the beginning of systematic studies of synthesis and characterization of cyclic polymers, this field has rapidly expanded and the number of publications has tremendously increased. Cyclization of linear polymers is of great fundamental interest for comparison with the formation of cyclic biopolymers and for understanding the effect of cyclization on polymer properties. Technical applications of cyclic polymers have not been reported yet, mainly because of the lack of appropriate synthesis methods suitable for large-scale production. Cyclic polymers may be useful in smaller quantities as additives to linear polymers for fine-tuning of the rheological properties. We may expert that the high research activity in this field will favor further important developments. 

Figure 8.13 Cyclization of linear polymers by thiol-based click reaction to form cyclic polymer.

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