A NOVEL METHOD TO IMPROVE DIELECTRIC PROPERTIES IN CONDUCTIVE FILLER / POLYMER COMPOSITES M. Arjmand, U. Sundararaj Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, Canada PPS – 28 Dec 11-15, thailand

Embedded Capacitor In a typical microelectronic product, around 80% of the electronic components are passive components, such as capacitors, which take up more than 40% of the printed circuit board (PCB) surface area.1 2 1J. X. Lu, K. S. Moon, J. W. Xu, and C. P. Wong, J. Mater. Chem. 16 (16), 1543 (2006). 2www.murata.com

Chronological Development of Capacitors Conventional Capacitors like Ceramic Capacitors High-k Ceramic Powder / Polymer Capacitors Conductive Filler / Polymer Capacitors (CPCs)

What Makes CPCs Different For Use As Charge Storage Material? (Cont’d) The electric dipole has a magnitude equals to the strength of each charge times the separation between charges. Interfacial Polarization + + + + - + + + + + Electronic Polarization

Challenges in Manipulating CPCs as Charge Storage Materials High real permittivity is achievable close to or above percolation threshold.1 The insulator–conductor transition, which occurs at percolation threshold, precludes CPCs from being used above the percolation threshold. There is a typically narrow insulator-conductor transition window to regulate dielectric properties. 1Dang ZM, Yao SH, Yuan JK, and Bai JB. J Phys Chem C 2010; 114: 13204-9.

Strategies to Avoid Sharp Insulator – Conductor Transition Covering the Surface of Conductive Filler with an Insulative Layer Introducing Secondary Particle as Insulating Barrier

Conductive Filler Alignment: A Novel Approach to Improve Dielectric Properties The Inverse Relationship Between MWCNT Alignment and Electrical Conductivity1 The Direct Relationship Between Electrical Conductivity and Imaginary Permittivity Compression Molding Injection Molding Arjmand M, Mahmoodi M, Gelves GA, Park S, and Sundararaj U. Carbon 2011; 49: 3430-40.1

Experimental (Cont’d) Injection Molding BOY 12A Polystyrene Masterbatch 20 wt% (MB2020-00) Blending with Twin-Screw Extruder “Coperion ZSK” Compression Molding Pure Polystyrene (Styron® 610)

Processing Parameters Experimental Composite Molding Compression Molding: Carver Plate Press: 210 oC, 38 MPa, 10 min Injection Molding Processing Parameters 240 Injection Velocity (mm.s-1) 215 Melt Temperature (°C) 100 Injection Pressure (bar) 60 Mold Temperature

Morphological Analysis Injection Molding Compression Molding

Effect of Alignment on Insulator – Conductor Transition Window 0.7 – 2.0 wt% 5.0 – 8.5 wt%

Conceptualization of the Effects of Alignment on Real and Imaginary Permittivities + + - + + + + - + +

Effects of Alignment on Imaginary Permittivity

Effects of Alignment on Real Permittivity

Effects of Alignment on Dissipation Factor

Conclusions MWCNT alignment widened the typically narrow concentration window near the percolation threshold. The results showed that the MWCNT alignment reduces the dissipation factor in conductive filler / polymer composites. Due to industrial applications of injection molding process, the positive impact of MWCNT alignment on the dielectric properties is of high significance.

Acknowledgements Natural Sciences and Engineering Research Council of Canada (NSERC). Mr. Mahmoodi and Dr. Park, University of Calgary for assistance with the mold design and manufacturing. Mr. Apperley and Dr. Okoniewski, University of Calgary for assistance with electrical properties measurements. Americas Styrenics LLC, for providing pure polystyrene.

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Injection Molding vs Compression Molding: Length Distribution

Raman spectroscopy ratios parallel/perpendicular Two significant characteristics in the Raman spectra of the MWCNT/polymer composites are the D band (disorder band), and the G band (graphite band). The Dװ/D ┴and Gװ/G ┴ parallel/perpendicular to the flow direction were used to determine the degree of MWCNT alignment. Raman spectroscopy ratios parallel/perpendicular ┴/DװD ┴/GװG Compression Molding 1.01 Injection Molding 1.66 1.51

Raman Spectroscopy

Rogers Corporation Product X-band Dielectric Properties Dielectric Constant Dissipation Factor Volume Resistivity (Ohm cm) R0 3003TM PTFE CERAMIC 3.00 0.0013 1018 R0 3203TM 3.02 0.0016 1013 R04003CTM HYDROCARBON CERAMIC 3.38 0.0029 1015 http://www.rogerscorp.com

Processing Parameters Experimental Injection Molding Our previous study showed that the melt temperature had the greatest impact on MWCNT alignment followed by the injection velocity, while the impacts of mold temperature and injection/holding pressure were insignificant.1 Processing Parameters 240 Injection Velocity (mm.s-1) 215 Melt Temperature (°C) 100 Injection Pressure (bar) 60 Mold Temperature Parameter Value (mm) a 22.86 b 10.16 c, d 1 e 2 f 10 1 Mahmoodi M, Arjmand M, Sundararaj U, Park S. Carbon 2012; 50(4):1455-6423232323.