title: Fabrication and characterization of novel starch-grafted poly l-lactic acid/montmorillonite organoclay nanocomposites.
abstract: In this work, poly(L-lactic acid)-g-starch layered silicate nanocomposites (NCs) (PLLA-g-starch/MMT) were fabricated by intercalative bulk graft copolymerization of LA with starch, in the presence of either stannous octoate acting as a catalyst or LA-MMT organoclay acting as a cocatalyst-nanofiller. This procedure was performed inside a custom vacuum micro-reactor. To better understand the graft copolymerization mechanism, in situ processing types, interfacial interactions and nanostructure formation of PLLA-g-starch/MMT NCs, methods such as FT-IR, XRD, (1)H NMR, (13)C CP/MAS-NMR, DSC/TGA, TEM and SEM were utilized. The morphology and thermal behaviors of nanocomposites were found to be strongly dependent on the loading mass fraction of LA-MMT within the nanocomposite structure and the type of in situ processing such as interfacial, physical and chemical interactions. Preintercalated LA-MMT organoclay exhibited dual functions. It demonstrated the ability to act as a catalyst, essentially accelerating in situ graft copolymerization via esterification of LA carboxyl groups with hydroxyl groups of starch macromolecules, whilst also acting as a nananofiller-compatibilizer.
authors.affiliation: Department of Bioengineering, Faculty of Engineering and Natural Sicences, Gaziosmanpaşa University, 60150 Tokat, Turkey; Institute of Graduate Studies in Science, Division of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara, Turkey.
authors.forename: Özlem
authors.initials: Ö
authors.lastname: Eğri
authors.affiliation: Department of Chemical Engineering, Faculty of Engineering, Hacettepe University, Beytepe, 06800 Ankara, Turkey.
authors.forename: Kouroush
authors.initials: K
authors.lastname: Salimi
authors.affiliation: Department of Bioengineering, Faculty of Engineering and Natural Sicences, Gaziosmanpaşa University, 60150 Tokat, Turkey.
authors.forename: Sinan
authors.initials: S
authors.lastname: Eğri
authors.affiliation: Department of Chemical Engineering, Faculty of Engineering, Hacettepe University, Beytepe, 06800 Ankara, Turkey; Bionegineering R&D Center, Hacettepe University, Beytepe, 06800 Ankara, Turkey. Electronic address: piskin@hacettepe.edu.tr.
authors.forename: Erhan
authors.initials: E
authors.lastname: Pişkin
authors.affiliation: Institute of Graduate Studies in Science, Division of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara, Turkey. Electronic address: rzayevzmo@gmail.com.
authors.forename: Zakir M O
authors.initials: ZMO
authors.lastname: Rzayev
mesh_terms: D001546:Bentonite / Q000737:chemistry*; D019344:Lactic Acid / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D011091:Polyesters; D011108:Polymers / Q000737:chemistry*; D013213:Starch / Q000737:chemistry*
chemical_list: D011091:Polyesters; D011108:Polymers; D001546:Bentonite; D019344:Lactic Acid; C033616:poly(lactide); D013213:Starch
keywords: In situ graft copolymerization; Nanocomposites; Organoclay; Poly(lactic acid); Starch