Role of hierarchical morphology of helical carbon nanotube bundles on thermal expansion of polymer nanocomposites
- PDF / 429,344 Bytes
- 9 Pages / 584.957 x 782.986 pts Page_size
- 40 Downloads / 237 Views
Sergii G. Kravchenko School of Aeronautics and Astronautics, Purdue University, Indiana Manufacturing Institute, West Lafayette, Indiana 47906-1168, USA
Rocio Misiego SABIC, Murcia 30390, Spain
R. Byron Pipes School of Aeronautics and Astronautics, Materials Engineering and Chemical Engineering, Purdue University, Indiana Manufacturing Institute, West Lafayette, Indiana 47906-1168, USA
Ica Manas-Zloczower Department of Macromolecular Science and Engineering, Case School of Engineering, Case Western Reserve University, Cleveland, Ohio 44106-7202, USA (Received 3 March 2017; accepted 12 May 2017)
The thermal expansion behavior of polymer carbon nanotube (CNT) nanocomposites was investigated, and a micromechanical model was proposed to explain the highly nonlinear dependence of the coefficient of thermal expansion of the nanocomposite with CNT content for the CNT/polyimide nanocomposite. The microscopic analysis of CNT/polyimide matrix showed homogeneous dispersion of bundles composed of CNTs. Therefore, the proposed model to predict the thermal expansion behavior of the nanocomposite considered a random, homogeneous distribution of CNT bundles with a hierarchical arrangement of helical CNTs within the polymeric matrix. The CNT bundle morphology influenced the thermal expansion response of the nanocomposite through (i) bundle volume fraction and (ii) degree of helicity, affecting thermo-mechanical properties of the bundle. The effective, homogenized, properties of CNT bundles were determined by the elasticity based solution of the layered cylinder model. Bundle effective properties were used in the micromechanical model implementing the homogenized strain rule of the mixture expression to predict the thermal expansion behavior of nanocomposite in a wide range of CNT volume contents. The proposed micromechanical analytical model was found to correlate closely with the experimental results for polyimide/CNT nanocomposite films as measured using a digital image correlation method.
I. INTRODUCTION
Polymer based nanocomposites, both thermosetting and thermoplastic, find application in various engineering fields, including electronics, aeronautical, and biomedical applications.1 Carbon nanotube (CNT) reinforced polymers offer functional properties through improved electrical conductivity, mechanical reinforcement, and better thermal dimensional stability of the nanocomposite. The combination of high performance properties of polymers with mechanical, thermal, and electrical properties of CNTs can lead to nanocomposites exhibiting
Contributing Editor: Linda S. Schadler a) Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2017.214
light weight, mechanical strength, and enough electrical conductivity to prevent charge build-up. Furthermore, CNT nanocomposites incorporating microscopic fibers in a hierarchical multiscale composite can potentially improve the thermal dimensional stability by reducing the mismatch in thermo-elastic properties of the nanoreinforced matrix and the fibers, resu
Data Loading...
