title: Amino-Functionalized Multiwalled Carbon Nanotubes Lead to Successful Ring-Opening Polymerization of Poly(ε-caprolactone): Enhanced Interfacial Bonding and Optimized Mechanical Properties.
abstract: In this work, the synthesis, structural characteristics, interfacial bonding, and mechanical properties of poly(ε-caprolactone) (PCL) nanocomposites with small amounts (0.5, 1.0, and 2.5 wt %) of amino-functionalized multiwalled carbon nanotubes (f-MWCNTs) prepared by ring-opening polymerization (ROP) are reported. This method allows the creation of a covalent-bonding zone on the surface of nanotubes, which leads to efficient debundling and therefore satisfactory dispersion and effective load transfer in the nanocomposites. The high covalent grafting extent combined with the higher crystallinity provide the basis for a significant enhancement of the mechanical properties, which was detected in the composites with up to 1 wt % f-MWCNTs. Increasing filler concentration encourages intrinsic aggregation forces, which allow only minor grafting efficiency and poorer dispersion and hence inferior mechanical performance. f-MWCNTs also cause a significant improvement on the polymerization reaction of PCL. Indeed, the in situ polymerization kinetics studies reveal a significant decrease in the reaction temperature, by a factor of 30-40 °C, combined with accelerated the reaction kinetics during initiation and propagation and a drastically reduced effective activation energy.
authors.forename: Eleftheria
authors.initials: E
authors.lastname: Roumeli
authors.forename: Dimitrios G
authors.initials: DG
authors.lastname: Papageorgiou
authors.forename: Vasilios
authors.initials: V
authors.lastname: Tsanaktsis
authors.forename: Zoe
authors.initials: Z
authors.lastname: Terzopoulou
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Chrissafis
authors.affiliation: ⊥Polymers' Laboratory, Department of Materials Science Engineering, University of Ioannina, 45110 Ioannina, Greece.
authors.forename: Apostolos
authors.initials: A
authors.lastname: Avgeropoulos
authors.forename: Dimitrios N
authors.initials: DN
authors.lastname: Bikiaris
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry; D055119:Elastic Modulus; D006244:Hardness; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D011091:Polyesters / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D014783:Viscosity
chemical_list: D003432:Cross-Linking Reagents; D037742:Nanotubes, Carbon; D011091:Polyesters; C016240:polycaprolactone
keywords: in situ polymerization; mechanical properties; multiwalled carbon nanotubes; nanocomposites; poly(ε-caprolactone)