Synthesis of Polyrotaxane

Synthesis of Polyrotaxanes from Main Chain Pseudopoly rotaxanes... 

Table 14 Synthesis of polyrotaxanes by terminal coupling of stopper groups at polymer ICs with X coverage, number of CD tings per two polymer repeat units...

Fig. 2 The synthesis of polyrotaxane composed of multiple a-CD rings threaded and entrapped on a PEO chain [17]...

Synthesis of polyrotaxanes and polycatenanes is performed basically by using or applying the synthetic methods for rotaxanes and catenanes. 

It may be noted that besides chemical crosslink formation we can achieve the physical linking of macromolecules (Fig. 6) where the effect on propoties could be just as important as in chemical aosslinking and entanglements. The pertinence of such a procedures may be demonstrated by the synthesis of polyrotaxanes [197] in which a cyclic oligomer of ethylene oxide is absorbed on macromolecules of polyami (Scheme 1)... 

Fig. 1.34 Macrocycles that have been used in the synthesis of polyrotaxanes.

Fig. 1.45 Catalytically self-threading synthesis of polyrotaxane 7. (i) Please refer to Table 1.1 for details.

Most commonly crownether and cyclodextrin derivatives have been employed in the synthesis of supramolecular polymers. In more recent years cucurbituril, a macrocycle that has been known for almost a hundred years, has been discovered to be a versatile and unique building block for the synthesis of polyrotaxanes. 

Harada, A., Synthesis of Polyrotaxanes, Synthesis of Polymers (Schluter, A. -D. ed.), Wiley-VCH, Weinheim, 1999. 

Two principal approaches have been used in the synthesis of polyrotaxanes. In the statistical method, no specific interaction exists between the linear and the cyclic species. The equilibrium for threading is driven by entropic factors. This hence provides a wide choice of pairs of cyclics and linear chains. However, the resulting yield is often low. In the template or directed method, specific attractive interaction (such as metal chelation, charge transfer interactions, etc.) between the cyclic and the linear species is taken advantage of. 

Fig. 1 Demonstration of CD and polyrotaxane a structure of a-CD, b synthesis of polyrotaxane from a-CD and PEO-diamine [44]...

Thus, the studies of the directed synthesis of polyrotaxanes indicate the necessity of a preliminary ordering of the system (association, channel complexes of inclusion compounds). It should be pointed out that the above-described ways for the ordering are limited by a restricted choice of both macrocycles (p-cyclodextrin) and linear polymers (polyvinylidene chloride and its copolymer with allyl chloride and... 

Synthesis of Polyrotaxanes with the Use of Swarm Complexes and Investigation of Their Structure... 

Comparing the results of synthesis of polyrotaxanes based on the two cyclourethanes demonstrated that the degree of penetration of rings by the growing polymer chain in the polyrotaxanes tends to decrease by passing from CU-A to CU-B. For polyrotaxanes produced by the statistical method (PR-A2 and PR-B2) no changes are practically observed, but for the polymers synthesized in die presence of complexes with ZnClj the difference is marked (PR-Al and PR-Bl)... 

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