title: Effect of ZnO nanofillers treated with triethoxy caprylylsilane on the isothermal and non-isothermal crystallization of poly(lactic acid).
abstract: The crystallization of PLA-silane surface-treated ZnO nanocomposites was investigated by DSC and compared to that of neat PLA. Several modes of crystallization were considered: isothermal and non-isothermal cold crystallization and also isothermal and non-isothermal melt crystallization. The kinetics of cold crystallization were studied using different methods, namely the Avrami and Ozawa-Flynn-Wall models, to calculate activation energies and kinetic constants. In contrast to what is typically observed when the foreign particles are added in a polymer matrix, the silane surface-treated ZnO delayed the crystallization of PLA and made it more difficult to start. The nucleation activity of the ZnO nanoparticles, ϕ, was calculated and found to be greater than 1 (ϕ = 1.7). This indicated that ZnO played an anti-nucleating role in the crystallization of PLA nanocomposites. This effect has been linked mainly to the interactions between the silane groups onto the surface of nanoparticles and PLA macromolecules. These interactions which reduce the mobility of polymer chains have been evidenced by rheological experiments.
authors.affiliation: Institut de Chimie de Clermont-Ferrand, Equipe de Photochimie, avenue des Landais, BP 80026, 63171 Aubiere Cedex, France.
authors.forename: Pierre Olivier
authors.initials: PO
authors.lastname: Bussiere
authors.forename: Sandrine
authors.initials: S
authors.lastname: Therias
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Gardette
authors.forename: Marius
authors.initials: M
authors.lastname: Murariu
authors.forename: Philippe
authors.initials: P
authors.lastname: Dubois
authors.forename: Mohamed
authors.initials: M
authors.lastname: Baba
mesh_terms: D002152:Calorimetry, Differential Scanning; D003460:Crystallization; D019344:Lactic Acid / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D011091:Polyesters; D011108:Polymers / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry*; D013499:Surface Properties; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D011091:Polyesters; D011108:Polymers; D012821:Silanes; D019344:Lactic Acid; C033616:poly(lactide); D015034:Zinc Oxide