(Co)Polymerizations Of Hydrophobic Monomers In Aqueous Solution In The Presence Of Cyclodextrins

Cyclodextrins (CDs) can be used to build up host-guest complexes by inclusion of suitable hydrophobic molecules because of polar hydrophilic outer shell and relatively hydrophobic cavity. In this paper we use CDs to prepare poly(NIPAM-CD-GMA) temperature-sensitivity hydrogels, latex of poly(glycidyl methacrylate-co-α-methyl styrene), and poly(p-methyl phenacyl methacrylate).Poly(NIPAM-CD-GMA) temperature-sensitivity hydrogel was prepared by copolymerization of hydroxypropyl-β-cyclodextrin (HP-P-CD)/ glycidyl methacrylate(GMA)/N-isopropylacrylamide (NIPAM) system. In this system, GMA played three-fold roles, that is, as a carrier to introduce CD moieties into the network, as a comonomer and as a crosslinking agent via the ring-opening reactions of the epoxide groups and/or via the reactions of GMA and CD. Appropriately increase the contents of CD and GMA is favorable to improve the swelling ratio and temperaturesensitivity of the resulting hydrogels. Poly (NIPAM-CD-GMA) hydrogels displayed higher swelling ratios and rapid temperature-responsivity when compared with the poly(NIPAM-GMA) hydrogels without CD. This novel crosslinking technique based on HP-β-CD/GMA system is of interest for the preparation of functional polymers, especially those requiring crosslinking structures.Another important application of CD is used in emulsion polymerization. The average particle size (APS) of poly(glycidyl methacrylate) latexes are between 149 and 790 nm, and the particle-size distribution (PSD) was between 0.01 and 0.4, while the APS and PSD of GMA-co-AMS latexes are betweenl28 and 149 nm, and 0.044 and 0.05, respectively. The APS of GMA-co-AMS latexes is small and the PSD is narrower than those in the poly(glycidyl methacrylate) latexes. It can also be found that the average particle size of poly(glycidyl methacrylate) latexes increased with increasing the concentration of CD. However, such an situation was not observed in GMA-co-AMS latexes.The molecular weight of poly(p-methyl phenacyl methacrylate) prepared in CD water solution is similar to that prepared in organic solution. This demonstrates that the polymerization of p-methyl phenacyl methacrylate can occur in water in the presence of CD. Poly(p-methyl phenacyl methacrylate) obtained in aqueous solution in the presence of CD showed higher thermal stability than that prepared in organic solvent, because the CD present in the polymer can improve the thermal stability of poly(p-methyl phenacyl methacrylate). The reusability of CD was attested.