title: Polydisperse methyl β-cyclodextrin-epichlorohydrin polymers: variable contact time (13)C CP-MAS solid-state NMR characterization.
abstract: The polymerization of partially methylated β-cyclodextrin (CRYSMEB) with epichlorohydrin was carried out in the presence of a known amount of toluene as imprinting agent. Three different preparations (D1, D2 and D3) of imprinted polymers were obtained and characterized by solid-state (13)C NMR spectroscopy under cross-polarization magic angle spinning (CP-MAS) conditions. The polymers were prepared by using the same synthetic conditions but with different molar ratios of imprinting agent/monomer, leading to morphologically equivalent materials but with different absorption properties. The main purpose of the work was to find a suitable spectroscopic descriptor accounting for the different imprinting process in three homogeneous polymeric networks. The polymers were characterized by studying the kinetics of the cross-polarization process. This approach is based on variable contact time CP-MAS spectra, referred to as VCP-MAS. The analysis of the VCP-MAS spectra provided two relaxation parameters: T CH (the CP time constant) and T 1ρ (the proton spin-lattice relaxation time in the rotating frame). The results and the analysis presented in the paper pointed out that T CH is sensitive to the imprinting process, showing variations related to the toluene/cyclodextrin molar ratio used for the preparation of the materials. Conversely, the observed values of T 1ρ did not show dramatic variations with the imprinting protocol, but rather confirmed that the three polymers are morphologically similar. Thus the combined use of T CH and T 1ρ can be helpful for the characterization and fine tuning of imprinted polymeric matrices.
authors.affiliation: ULCO, UCEIV, F-59140 Dunkerque, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Mallard
authors.affiliation: ULCO, UCEIV, F-59140 Dunkerque, France; UCLille, EA GRIIOT (4481), Laboratoire de Pharmacochimie, HEI, 13 rue de Toul, F-59046 Lille, France; UFR Pharmacie, EA GRIIOT (4481), Laboratoire de Chimie Analytique, BP 83, F-59006 Lille, France.
authors.forename: Davy
authors.initials: D
authors.lastname: Baudelet
authors.affiliation: Dipartimento di Chimica, Materiali ed Ingegneria Chimica 'G. Natta' Politecnico di Milano, Piazza L. da Vinci 32, I-20133 Milano, Italy.
authors.forename: Franca
authors.initials: F
authors.lastname: Castiglione
authors.affiliation: Dipartimento di Chimica, Materiali ed Ingegneria Chimica 'G. Natta' Politecnico di Milano, Piazza L. da Vinci 32, I-20133 Milano, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Ferro
authors.affiliation: CNR-ICRM, Via L. Mancinelli 7, I-20131 Milano, Italy.
authors.forename: Walter
authors.initials: W
authors.lastname: Panzeri
authors.affiliation: Dipartimento di Scienze Molecolari Agroalimentari, Università di Milano, Via Celoria, 2 I-20133 Milano, Italy.
authors.forename: Enzio
authors.initials: E
authors.lastname: Ragg
authors.affiliation: Dipartimento di Chimica, Materiali ed Ingegneria Chimica 'G. Natta' Politecnico di Milano, Piazza L. da Vinci 32, I-20133 Milano, Italy; CNR-ICRM, Via L. Mancinelli 7, I-20131 Milano, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Mele
keywords: dynamic cross-polarization; epichlorohydrin; imprinted; insoluble CRYSMEB polymers; solid-state NMR spectroscopy