Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2013 Cyanate ester-nanoparticle composites as multifunctional structural capacitors José Eliseo De León Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Mechanics of Materials Commons Recommended Citation De León, José Eliseo, "Cyanate ester-nanoparticle composites as multifunctional structural capacitors" (2013). Graduate Theses and Dissertations. 13353. https://lib.dr.iastate.edu/etd/13353 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Cyanate ester-nanoparticle composites as multifunctional structural capacitors by J. Eliseo De León Dissertation submitted to the faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Materials Science and Engineering Program of Study Committee Members: Michael R. Kessler, Major Professor Nicola Bowler Xioali Tan David Grewell Vinay Dayal Iowa State University Ames, IA 2013 ii TABLE OF CONTENTS LIST OF TABLES ........................................................................................................... iv LIST OF FIGURES .......................................................................................................... v ABSTRACT ..................................................................................................................... vii CHAPTER 1. Introduction........................................................................................ 1 Background and Motivation ....................................................................................... 1 Multifunctionality ....................................................................................................... 2 Research Objective ..................................................................................................... 6 CHAPTER 2. Early findings ................................................................................... 17 MWCNT and BaTiO3 PMCs prepared with MMT modified BECy resin................ 17 GF PMCs prepared with BaTiO3 modified BECy resin ........................................... 19 Nanometer scale CCTO synthesis ............................................................................ 21 CHAPTER 3. Matching matrix and filler dielectric constants to increase dielectric breakdown strength ................................................................................... 22 Abstract ..................................................................................................................... 22 Introduction ............................................................................................................... 23 Processing and Dielectric Measurements ................................................................. 26 Results and Discussion ............................................................................................. 32 Conclusions ............................................................................................................... 38 CHAPTER 4. Modified cyanate ester resin polymer matrix composite used in structural capacitor applications.................................................................. 39 Abstract ..................................................................................................................... 39 Introduction ............................................................................................................... 39 Experimental ............................................................................................................. 44 Results and Discussion ............................................................................................. 47 Conclusions ............................................................................................................... 53 CHAPTER 5. Dielectric and thermo-mechanical behavior of multifunctional composites of carbon nanotubes and barium titanate embedded in a bisphenol E cyanate ester matrix ..................................................... 54 Abstract ..................................................................................................................... 54 Introduction ............................................................................................................... 54 Materials and Methods .............................................................................................. 58 Results and Discussion ............................................................................................. 62 Conclusions ............................................................................................................... 68 iii CHAPTER 6. Structural capacitors from cyanate ester and nanometer scale calcium copper titanate ..................................................................................... 71 Abstract ..................................................................................................................... 71 Introduction ............................................................................................................... 72 Experimental Procedure ............................................................................................ 75 Results and Discussion ............................................................................................. 79 Conclusion ................................................................................................................ 86 CHAPTER 7. Conclusions and future work .......................................................... 88 Experimental Conclusions ........................................................................................ 88 Implications and future directions ............................................................................ 94 APPENDIX………………………………………………………. ............................ 96 Processing Polymer Matrix Composites ................................................................... 96 Themo-mechanical and dielectric analytical methods .............................................. 99 BIBLIOGRAPHY ..................................................................................................... 102 iv LIST OF TABLES Table 2-1. Storage modulus and onset glass transition temperatures of PMCs prepared with 1 wt% MMT, 2.6 wt% MWCNT and various loadings of BaTiO3. ..............................18 Table 3-1. Calculated volume fraction loadings of dispersed BaTiO3 in E-glass PMCs. ....33 Table 4-1. Volume content of composite constituents for samples prepared with different amounts of BaTiO3. .................................................................................................48 Table 4-2. Room temperature E' of various BaTiO3 PMCs. .................................................50 Table 4-3. Effective dielectric constant of the composites with varying BaTiO3 vol% calculated using three different models. ................................................................................51 Table 5-1. Storage modulus of multifunctional composites at various BaTiO3 loadings. ....68 Table 6-1-Energy density values of prepared PMCs at various CCTO loadings. .................84 Table 6-2. Storage modulus and onset glass transition temperature of CCTO composites loaded to 10, 15 and 20 vol%..............................................................................85 Table 7-1. Tg and volume loading for each composite of the various experiments. .............92 Table 7-2. E' and filler volume loading of each BECy composite for the various experiments. ...........................................................................................................................93 v LIST OF FIGURES Figure 1-1. a) BECy monomer and b) cross-linked BECy thermoset ..................................7 Figure 1-2. Perovskite-like CCTO and BaTiO3 unit cell structures [36]. .............................8 Figure 1-3. Fiberglass PMC wetted and cured with BECy. ..................................................9 Figure 1-4. Electric field concentration increases along x-direction (normal to applied voltage) in vicinity of inclusion with radius 0.5 A.U. [48]. ......................................12 Figure 2-1. DMA indicates a decrease in Tg with BaTiO3 loading, when the composite system of BECy, MMT, MWCNT and BaTiO3 is cured together. ......................18 Figure 2-2. ′ and tan of neat BECy is shown in light colors, while the composite values are shown in dark colors. The composite indicates an improvement in ′ 8x to 10x that of the neat resin. ..........................................................................................19 Figure 2-3. DMA curves of various wt% BaTiO3 4-ply BECy/BaTiO3 slurry in GF composites. Room temperature E’ increases as a function of increased BaTiO3 loading. ...20 Figure 2-4. Dielectric constant and dissipative loss curves for 25, 30, 40 wt% BaTiO3 loading in BECy/GF 4-ply system composite over a range of frequencies at room temperature. ...........................................................................................................................21 Figure 3-1. Bruggeman model of effective dielectric