Flow induced orientation of multiwalled carbon nanotubes in polycarbonate nanocomposites: Rheology, conductivity and mechanical properties

We investigated the effect of flow field and deformation rate on the nanotube alignment and on the properties of PC/multiwalled carbon nanotube nanocomposites. Samples of various MWCNT loadings were prepared by diluting a commercial masterbatch containing 15 wt% nanotubes using optimized melt mixing conditions. Different processing conditions were then used to systematically change the degree of nanotube alignment, from random orientation to highly aligned. Morphological studies and Raman spectroscopy analysis revealed that the nanotubes are preferentially aligned in the flow direction, particularly at large injection or compression rates. Rheological measurements corresponding to high shear rate conditions showed drastic changes in the viscoelastic behavior. The complex viscosity significantly decreased and percolation threshold notably rose. High degrees of nanotube alignment also resulted in a significant increase in the electrical percolation threshold. The mechanical properties of the nanocomposites for different nanotube loadings were also shown to depend on the processing conditions, and somehow improved when the material was processed at higher rates. Finally, we used a power-law type equation to correlate the percolation behavior and the nanotube alignment. The estimated percolation threshold and the power index, q, significantly increase with the degree of nanotube alignment as determined by Raman analysis.

[1]  S. Advani,et al.  Rheology of multiwall carbon nanotube suspensions , 2007 .

[2]  Donald R Paul,et al.  Rheological behavior of multiwalled carbon nanotube/polycarbonate composites , 2002 .

[3]  James M Tour,et al.  Rheological behaviour and mechanical characterization of injectable poly(propylene fumarate)/single-walled carbon nanotube composites for bone tissue engineering , 2005, Nanotechnology.

[4]  J. Laane,et al.  Studies of bisphenol-A polycarbonate aging by Raman difference spectroscopy , 2000 .

[5]  C. Friedrich,et al.  Mechanical properties and electrical conductivity of carbon-nanotube filled polyamide-6 and its blends with acrylonitrile/butadiene/styrene , 2004 .

[6]  Liang Wu,et al.  Rheological properties and crystallization behavior of multi-walled carbon nanotube /poly(ε -caprolactone) composites , 2007 .

[7]  P. Carreau,et al.  Rheological properties and percolation in suspensions of multiwalled carbon nanotubes in polycarbonate , 2009 .

[8]  Pj Piet Lemstra,et al.  Low percolation threshold in single-walled carbon nanotube/high density polyethylene composites prepared by melt processing technique , 2006 .

[9]  Frank T. Fisher,et al.  Direct Observation of Polymer Sheathing in Carbon Nanotube-Polycarbonate Composites , 2003 .

[10]  E. Thomas,et al.  Morphology and properties of melt-spun polycarbonate fibers containing single- and multi-wall carbon nanotubes , 2006 .

[11]  Maurizio Prato,et al.  Tensile Mechanics of Electrospun Multiwalled Nanotube/Poly(methyl methacrylate) Nanofibers , 2007 .

[12]  Meyya Meyyappan,et al.  Carbon Nanotubes: Science and Applications , 2007 .

[13]  Liangchi Zhang,et al.  Mechanical and rheological properties of carbon nanotube-reinforced polyethylene composites , 2007 .

[14]  Petra Pötschke,et al.  Carbon nanotube-filled polycarbonate composites produced by melt mixing and their use in blends with polyethylene , 2004 .

[15]  Ado Jorio,et al.  Carbon Nanotubes: Advanced Topics in the Synthesis, Structure, Properties and Applications , 2007 .

[16]  A. G. Kurenya,et al.  Effect of nitrogen doping on Raman spectra of multi‐walled carbon nanotubes , 2008 .

[17]  Petra Pötschke,et al.  Rheological and dielectrical characterization of melt mixed polycarbonate-multiwalled carbon nanotube composites , 2004 .

[18]  M. C. Williams,et al.  Radial Flow of Non‐Newtonian Fluids Between Parallel Plates , 1974 .

[19]  J. Brisson,et al.  Morphological and orientation studies of injection moulded nylon-6,6/Kevlar composites , 1994 .

[20]  M. Dresselhaus,et al.  Comparison study of semi-crystalline and highly crystalline multiwalled carbon nanotubes , 2001 .

[21]  M. Moniruzzaman,et al.  Polymer Nanocomposites Containing Carbon Nanotubes , 2006 .

[22]  Guangjun Hu,et al.  Low percolation thresholds of electrical conductivity and rheology in poly(ethylene terephthalate) through the networks of multi-walled carbon nanotubes , 2006 .

[23]  Satish Kumar,et al.  Oriented and exfoliated single wall carbon nanotubes in polyacrylonitrile , 2006 .

[24]  M. Shaffer,et al.  Analogies between polymer solutions and carbon nanotube dispersions , 1999 .

[25]  R. Miller,et al.  Long‐Range, Entangled Carbon Nanotube Networks in Polycarbonate , 2003 .

[26]  Jack F Douglas,et al.  Flow-induced properties of nanotube-filled polymer materials , 2004, Nature materials.

[27]  C. Domingo,et al.  Templating of crystallization and shear-induced self-assembly of single-wall carbon nanotubes in a polymer-nanocomposite , 2006 .

[28]  Liang Wu,et al.  Rheology of multi‐walled carbon nanotube/poly(butylene terephthalate) composites , 2007 .

[29]  Micah J. Green,et al.  NANOTUBES AS POLYMERS , 2009 .

[30]  A. Rinzler,et al.  ALIGNED SINGLE-WALL CARBON NANOTUBES IN COMPOSITES BY MELT PROCESSING METHODS , 2000 .

[31]  Otto Zhou,et al.  Alignment of carbon nanotubes in a polymer matrix by mechanical stretching , 1998 .

[32]  J. Jehng,et al.  The formation mechanisms of multi-wall carbon nanotubes over the Ni modified MCM-41 catalysts , 2008 .

[33]  J. Joo,et al.  Rheological and electrical properties of polycarbonate/multi-walled carbon nanotube composites , 2006 .

[34]  H. Choi,et al.  Nanofibrous Membranes Prepared by Multiwalled Carbon Nanotube/Poly(methyl methacrylate) Composites , 2004 .

[35]  Donald G. Baird,et al.  Polymer Processing: Principles and Design , 1995 .

[36]  J. Fischer,et al.  Effect of nanotube alignment on percolation conductivity in carbon nanotube/polymer composites , 2005 .

[37]  H. Brünig,et al.  Orientation of multiwalled carbon nanotubes in composites with polycarbonate by melt spinning , 2005 .

[38]  V. Bliznyuk,et al.  Matrix mediated alignment of single wall carbon nanotubes in polymer composite films , 2006 .

[39]  Wei Zhou,et al.  Nanotube Networks in Polymer Nanocomposites: Rheology and Electrical Conductivity , 2004 .

[40]  Rao,et al.  Polarized raman study of aligned multiwalled carbon nanotubes , 2000, Physical review letters.

[41]  Tsu-Wei Chou,et al.  Nanocomposites in context , 2005 .

[42]  H. Wagner,et al.  Raman spectroscopy of carbon–nanotube–based composites , 2004, Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.

[43]  Chuck Zhang,et al.  Mechanical and electrical properties of polycarbonate nanotube buckypaper composite sheets , 2008, Nanotechnology.

[44]  M. Abdel-Goad,et al.  Rheological characterization of melt processed polycarbonate-multiwalled carbon nanotube composites , 2005 .

[45]  Z. Tadmor.  Molecular orientation in injection molding , 1974 .

[46]  D. Litchfield,et al.  The role of nanoclay in the generation of poly(ethylene terephthalate) fibers with improved modulus and tenacity , 2008 .