title: Micro-mechanics of nanostructured carbon/shape memory polymer hybrid thin film.
abstract: This paper investigates the mechanics of hybrid shape memory polymer polystrene (PS) based nanocomposites with skeletal structures of CNFs/MWCNTs formed inside. Experimental results showed an increase of glass transition temperature (Tg) with CNF/MWCNT concentrations instead of a decrease of Tg in nanocomposites filled by spherical particles, and an increase in mechanical properties on both macro- and μm-scales. Compared with CNFs, MWCNTs showed a better mechanical enhancement for PS nanocomposites due to their uniform distribution in the nanocomposites. In nanoindentation tests using the Berkovich tips, indentation size effects and pile-up effects appeared obviously for the nanocomposites, but not for pure PS. Experimental results revealed the enhancement mechanisms of CNFs/MWCNTs related to the secondary structures formed by nanofillers, including two aspects, i.e., filler-polymer interfacial connections and geometrical factors of nanofillers. The filler-polymer interfacial connections were strongly dependent on temperature, thus leading to the opposite changing trend of loss tangent with nanofiller concentrations, respectively, at low and high temperature. The geometrical factors of nanofillers were related to testing scales, further leading to the appearance of pile-up effects for nanocomposites in the nanoindentation tests, in which the size of indents was close to the size of the nanofiller skeleton.
authors.affiliation: National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin 150080, People's Republic of China. luhb@hit.edu.cn and Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK. Richard.fu@northumbria.ac.uk.
authors.forename: Ming
authors.initials: M
authors.lastname: Lei
authors.affiliation: Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK. Richard.fu@northumbria.ac.uk.
authors.forename: Ben
authors.initials: B
authors.lastname: Xu
authors.affiliation: Faculty of Mathematics and Natural Sciences, Advanced Production Engineering - Engineering and Technology Institute Groningen, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Yutao
authors.initials: Y
authors.lastname: Pei
authors.affiliation: National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin 150080, People's Republic of China. luhb@hit.edu.cn.
authors.forename: Haibao
authors.initials: H
authors.lastname: Lu
authors.affiliation: Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK. Richard.fu@northumbria.ac.uk.
authors.forename: Yong Qing
authors.initials: YQ
authors.lastname: Fu