Hydrolyzed cyclocopolymer prepared from divinyl ether and maleic anhydride, poly[(divinyl ether)-co-(maleic anhydride)] (DIVEMA), was functionalized with aminoadamantane and subsequently compared with the hydrolyzed DIVEMA with respect to physicochemical properties. The complexation behavior of adamantyl modified DIVEMA with cyclodextrin derivatives was examined by dynamic light scattering, nuclear magnetic resonance spectroscopy and zeta potential. The scattering studies indicated the formation of well-defined aggregated structures with an average diameter of 120 nm. These aggregated structures collapsed on addition of randomly methylated β-cyclodextrin to give 4.2 nm in hydrodynamic diameter. Interactions with crosslinked β-cyclodextrins indicated gel formation which was analyzed by means of rheology and temperature-dependent viscosity showing disaggregation of the host-guest system at 42 • C. This novel physical hydrogel is very interesting for medical applications as a drug delivery system with included anti-tumor activity.
N‐vinylcaprolactam (NVCL) is modified via alkylation at the α‐position. The α‐substituents are ethyl (3‐ethyl‐1‐vinylcaprolactam), dodecyl (3‐dodecyl‐1‐vinylcaprolactam), octadecyl (3‐octadecyl‐1‐vinylcaprolactam), 1‐propanol (3‐(3‐hydroxy‐propyl)‐1‐vinylcaprolactam), and PEG3 bromide (3‐PEG3‐bromide‐1‐vinylcaprolactam). These monomers are homo‐ and copolymerized with N‐(4‐methylphenyl)maleimide by the free radical mechanism. The structures of the obtained polymers are characterized by means of 1H NMR and IR spectroscopy, gel permeation chromatography (GPC), and by use of differential scanning calorimetry (DSC) (Tg).
Randomly methylated β -cyclodextrin (me-β -CD) is used to include the hydrophobic monomer N -(4-methylphenyl)maleimide (MPM) ( 1 ) yielding the corresponding water-soluble host-guest structure 1a . Free-radical copolymerization of 1a with N -vinylpyrrolidone (NVP) ( 2 ) is performed and the reactivity ratios r 1 and r 2 are determined: 0.24 ± 0.03 ( r 2 ) and 1.10 ± 0.05 ( r 1a ). This indicates a preferred incorporation of complexed maleimide into the copolymer chain. In contrast to that, the copolymerization of the uncomplexed monomers 1 and 2 is carried out using organic solvent (DMF/H 2 O) showing reactivity ratios corresponding to nearly alternating copolymerization ( r 2 = 0.09 ± 0.02; r 1 = 0.34 ± 0.03).
Hydroxyalkylation of N -vinylcaprolactam (NVCL) in α -position via ring-opening reaction of propylene oxide and ε -caprolactone, respectively, yields in precursors for multifunctional NVCL derivatives. Homo-and copolymers of hydroxyfunctionalized NVCL derivatives, synthesized by free radical mechanism, are further investigated regarding their thermoresponsive behavior. Esterifi cation of hydroxypropylated NVCL derivative with methacrylic anhydride is carried out yielding a versatile bifunctional cross-linker. Networks are obtained either via free radical polymerization of the cross-linker or anionic polymerization of only the methacrylic function and subsequent polymer analogous cross-linking of the vinylic side groups. The rheological behavior during and after curing is investigated by oscillatory rheology. Furthermore, N -vinylcaprolactam anion is used as an initiator for the anionic ring-opening polymerization of ε -caprolactone. Copolymerization of poly( ε -caprolactone) macromonomer with NVCL yields graft copolymers. A polymerizable thermotropic liquid crystalline (LC) derivative is prepared by coupling cholesteryl chloroformate to NVCL. The thermal behavior of LC derivative is investigated by differential scanning calorimetry and polarized light microscopy.
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