Preparation And Characterization Of Cyclodextrin-based Poly (Pseudo) Rotaxane

As implied by their names, polypseudorotaxanes/polyrotaxanes are constructed simply by incorporating pseudorotaxane/ rotaxane moieties into linear polymers for which the connecting force are non-covalent interaction, the linear polymer molecule of polyrotaxanes have two bulky end-capping groups which polypseudorotaxanes have not. Cyclodextrins are one of the most important host of poly (pseudo)rotaxanes, assembly between cyclodextrine (CD) and polymer have attracted growing attention due to their selectivity, regulation and control, and bio-compatibility. In this paper, several methods are tried to prepare cyclodextrin-based poly (pseudo)rotaxanes, the productions are characterized by FT-IR, ¹H-NMR, DSC, XRD, UV-Vis spectra, high-resolution transmission electron microscopy, et al. Our research was conducted from following aspects.Firstly, the contents ofβ-CD are determined by a new quantitative analysis method using UV-vis spectra, the result show that at least 77 polymeric mers contain single CD, combined with XRD spectra of polymerization production of hydrophobic monomer BMA in CD solution, it is easy to conclude that we can not obtain cyclodextrin-based polyrotaxane by this way.The influence of various kinds of CDs and different concentrations to reaction speed, particle size and particle size index distribution of emulsifier-free emulsion polymerization of BMA, MMA is studied respectively. The results show that CDs accelerate the reaction speed of the emulsifier-free emulsion polymerization, the mechanism of polymerization of BMA in CDs solution can be explained as homo-phase nucleus-forming mechanism under phase-transfer catalyzing (HN-PTC), CD could improve reaction speed and monomer conversion effectively, especially when the concentration of CDs is higher than the critical concentration, the particle size of latex become bigger and PSI become narrow. Whereas, when concentration of CDs is lower than a given value, the polymerization of MMA is following homo-phase nucleus-forming mechanism (HN), with the increase of CDs' concentration, the mechanism of HN-PTC influence the polymerization of MMA more. HN-PTC is described for the first time and coincide the experiment result very well. In addition,α-,β-,γ-CD influence emulsifier-free emulsion polymerization differently, the sequence of CDs accelerate reaction speed of BMA isα-CD<β-CD<γ-CD, while it isα-CD >β-CD >γ-CD for BMA.A function monomer SEM-25 with a double-bond in one end and a polyphenyl groups in the other ends is selected to interact withα-,β-,γ-CD. Through several measures such as FT-IR, ¹H-NMR, DSC, XRD, UV-Vis spectra, high-resolution transmission electron microscopy to characterize the production, the results indicate that the "channel type" crystal - polypseudorotaxane (AS) is prepared successfully by mixing SEM-25 andα-CD saturated solution. Reaction temperature higher than 15℃is necessary to prepare AS. In addition, we can not obtain inclusion complex between SEM-25 andβ-CD, and the inclusion complex by SEM-25 andβ-CD is proved as amorphous matter (YS).Then, we explore various way to polymerize polypseudorotaxane AS to prepare aim production-side chain polyrotaxane. Water-soluble initiator K₂S₂O₈ (KPS) and oil-soluble initiator AIBN are used to homopolymerize AS, however, it does not work. It is the same result as KPS initiate the homopolymerization of AS and BMA. Take (NH₄)₂S₂O₈-NaHSO₃ as initiator, MMA as the copolymerizing monomer, the club-shaped cyclodextrin-based side chain polyrotaxane are prepared successfully. it is the first time to prepare side-chain polyrotaxane by the way of free radical copolymerization.The interaction betweenα-,β-,γ-CD and eight dendrimers conprising of G0(PhBr)- G3(PhBr) and G0(5F)- G3(5F) are studied. The inclusion complex between 0 generation dendrimers andα-,β-,γ-CD are prepared. But it is more difficult to form inclusion complex between CDs and dendrimers which is more than 1 generation.