CNT Thermoplast Composites: Two Examples for Potential Applications

Transcription

1 CNT Thermoplast Composites: Two Examples for Potential Applications Dr.-Ing. Petra Pötschke Department of Functional Nanocomposites and Blends Leibniz Institute of Polymer Research Dresden (IPF) Hohe Str. 6, Dresden German-Japanese Workshop on the Commercial Use of Nanocarbons Tokyo, Tuesday, January 29, 2013, 10:00 17:00 1

2 IPF Dresden IPF Dresden a research institute of the Gottfried Wilhelm Leibniz Science Association (WGL) WGL = total of 84 research institutes and service facilities funded jointly by the Federal Government and the Länder as a result of its supraregional importance and in the interest of national science policy. " Research at IPF on composites with CNTs - in the sense of application oriented basic research (as it is the task of WGL) - exploration of basic relationships - experiments in small scale towards laboratory scale - cooperation with industry mainly without direct applications - use of the potential of IPF as the largest polymer research institute in Germany (500 coworkers, cooperation of chemists, physisists, engineers, biologists, mathematicians, ) Theoria cum praxi 2

3 Outline Aim of the work at IPF: Investigation of factors influencing the dispersion of CNTs in polymeric matrices Effect on different polymer properties Potential Applications Structure of the lecture: 1) Examples for research directions at IPF Dresden 2) Example 1: Body car panel 5) Example 2: Textile with sensory properties 6) Outlook 3

4 CNT composites - directions of research at IPF antistatic housings electrostatically paintable parts (e.g. body panel) antistatic tubes and pipes surfaces suitable for powder coatings conductive foam structures conductive melt-spun fibers sensory materials, e.g. für liquid sensing optimised tire materials cable with balanced strength/conductivity profile enhanced glass fiber composites housing Body panel fibers foams powder coated surfaces cables 4

5 BMBF project Lightweight construction with thermoplastic nanocomposites (LB-Nanos) Material developement and characterisation (Leichtbau mit thermoplastischen Nanocomposites (LB-Nanos) - Werkstoffentwicklung und charakterisierung) Support number (FKZ) 03X3006E, till , final report Aim of the project Example 1: Car body panel Development of thermoplastic nanocomposites for the production of exterior add-on parts under consideration of : weight reduction (plastics replace metals) dimension stability online paintability (using cataphoretic painting, short term till 205 C) high heat resistance low CTE (coefficient of thermal expansion) electrical conductivity surface quality (e.g. gloss) Optimisation of commercialpa6/pa66/ppe blend systems by use of nanoscaled additives A) layered silicates: improved stiffness, strength and thermal stability at nearly constant material density and toughness B) CNTs: for electrical conductivity, replacement of carbon black to improve mechanical properties 5

6 Example 1: Car body panel IPF Dresden: development of the technology for nanocomposite production formulation optimization characterization of electrical peroperties of the composites and parts Süd-Chemie: modification and development of new layered silicate formulations testing of suitable additives for pre-exfoliation of organically modified layered silicates Supply of larger amounts of layered silicate masterbatches IFW Dresden: synthesis of defined MWCNTs modification MWCNTs, SWCNTs (functionalization, coating) supply of necessary amounts of MWCNTs, SWCNTs characterization of CNTs Daimler AG: project coordination definition of requirements demonstrator assembly investigations on ready parts assessment suitability for mass production Sabic Innovative Plastics: validation of nanocomposite technology in PA/PPE coordination of new material development activities material characterization rheological characterization development of screws 6

7 Example 1: Car body panel Melt mixing trials in small scale: Comparison of different CNT types in PA66 on electrical percolation threshold wt% volume conductivity [S/cm] wt% 0.35 wt% 0.81 wt% 1.02 wt% solid bed CNT (16 at% Fe) solid bed CNT (4 at% Fe) solid bed (1 at% Fe) aerosol CNT (without N) aerosol CNT (with N) commercial CNT NC CNT content [wt%] 280 C, 50 rpm, 5 min 320 C, 2 min I Extremely low percolation threshold of 0.04 wt% for CNTs produced by the aerosol method in PA66 Krause et al. CSTE 2010, 70 (1), U

8 Example 1: Car body panel Slurry feeding of layered silicates (LS) common feeding with CNTs Twin-screw extruder Leistritz Micro 27 with slurry feeding Exfoliation of layered silicates in PA6 Comparison: dry feeding vs. slurry (layered silicates swollen in water) wt% layered silicate (LS) complex viscosity [Pa s] slurry feeding with the worsely exfoliating LS dry feeding with a worsely exfoliating LS (nonmodified) dry feeding with a well exfoliating LS Hagenaars et al. US patent Improvement of exfoliation of LS using the slurry feeding common feeding with CNTs in the slurry possible, leads to good CNT dispersion 10 2 frequency [rad/s] 8

9 Example 1: Car body panel PA + layered silicate TEM PA + layered silicate + CNT 4 wt% layered silicate 3.4 wt% layered silicate wt% CNT Good exfoliation of LS and dispersion of CNTs using slurry feeding 9

10 Example 1: Car body panel Morphology of PA/PPE blends PA/PPE with CNT and organically modified layered silicate Desctruction of the blend morphology needed for good properties PA/PPE (reference) PA/PPE with CNT und unmodified layered silicate using slurry feeding Remaining of basic morphology (good properties) 10

11 Example 1: Car body panel Demonstrator part Painted Olympiatool dimensions: 70 cm x 45 cm Car body panel Mercedes S class weight : 1.9 kg Material extrusion: IPF Dresden, Sabic IP Injection molding, painting: Sabic IP, Bergen op Zoom Mechanical testing: Daimler AG Material extrusion: IPF Dresden, Sabic IP Injection molding: Sabic IP, Bergen op Zoom Painting: Daimler AG, Sindelfingen Mechanical testing: Daimler AG 11

12 Example 1: Car body panel Demonstrator part Assessment of suitability for mass production: numeric simulations Testing of the demonstrator parts crush tests paint bonding (steam jet, multi-impact stonechipping tests) pendulum and head impact tests water uptake, recristallisation, thermal expansion 12

13 Example 1: Car body panel Summary Carbon Nanotubes Using the aerosol method, an alternative CNT synthesis method could be developed in the laboratory scale, which shows a high potential concerning the achievable conductivity in composites as well as production costs. Layered silicates +CNTs Using the slurry feeding it was possible, to introduce unmodified layered silicates in combination with CNTs into polyamide and multiphase PA/PPE blends under preservation of the complex morphology of the blend. PA/PPE + Layered silicates + CNTs Demonstrator parts were produced and assessed concerning the market readiness of the new material. The nanocomposite combination has high potential for property improvements. Technology development Common incorporation of layered silicates and CNTs using the slurry approach was succesfully shown. Ready-to-use material is expecting its prospective use! 13

14 Example 2: Textile with sensory properties Use of CNTs in polymeric fibers for Sensing textiles INTELligent Multi-reactive TEXtiles integrating nano-filler based Conductive Polymer Composite (CPC) fibers. European project (6. FP) (September 2006 till August 2010) 23 partners (8 research and 15 industrial partners, mainly SME) Idea: Development of textile structures with fibers, which are able to detect vapors, liquids, deformation, and temperature changes, whereby the fibers themselves act as the sensor, for medical, construction and safety clothes applications. 14

15 Example 2: Textile with sensory properties Sensing principle Changes in temperature, and/or mechanical deformation, and the presence of vapor and liquid molecules result in structural changes of the conductive filler network leading to variations in the electrical resistivity. Within the project: CNTs as conductive fillers in CPCs nanotube Electrical Resistance R ( ) 1 swelling 3 2 shrinkage 4 5 R 0 time [s] 15

16 systematic variation of extrusion conditions (screw configuration, rotation speed, throughput, temperature profile) Influence on CNT dispersion excellent CNT disopersion as precondition for spinnability Example: PLA (polylactid acid) + MWCNT NC7000 Electrical volume resistivity [ cm] Example 2: Textile with sensory properties 1. Production of composite materials (PLA, PCL, PC, PBT, blends) PLA Biomer L Nanocyl N7000 (melt mixed under optimized conditions) Elektrostatically dissipative Berstorff ZE25 electrical conductive Dispersion Index [%] Dispersion Index [%] PLA masterbatches with 7.5 wt% CNT MB1 Dispersion Index D Number of agglomerates [number/mm²] MB2 TP2 Experiment MB3 MB4 Dilution towards 0.75 wt% CNT Dispersion Index [%] TP1 Number of agglomerates [n/mm²] TP1 TP2 temperature profile (TP) Number of agglomerates [number/mm²] Number of agglomerates [number/mm²] MWCNT content (wt%) rotation speed [min -1 ] Villmow et al. Polymer 49 (2008) 16,

17 Example 2: Textile with sensory properties 2. Melt spinning of nanocomposites comparison: resistivity fibers vs. Plate Small scale spinning line melt spun fiber PCL + 3 wt% CNT Problem! High anisotropy of CNT filled fibers TEM electrical resistance [ ] PCL+3.0 wt% CNT (pressed plate) fiber diameter [µm] electrical resistivity [ cm] Pötschke et al. Composites Science and Technology 70 (2010) 2,

18 Example 2: Textile with sensory properties 3. Liquid sensing tests/ experimental setup Sensing on pressed plates Sensing on melt spun fibers Electrodes Teflon caps Solvent Geometry Solvent level 3 mm 13 mm Pötschke et al. Composites Science and Technology 70 (2010) 2,

19 Example 2: Textile with sensory properties 3. Liquid sensing tests/ results Example: Fibers of PLA with CNT in ethanol / variation of CNT content relative resistance change R rel PLA wt% MWNT [Ri = 42.7 kohm] PLA wt% MWNT [Ri = 15.3 kohm] PLA wt% MWNT [Ri = 2.6 kohm] immersion Maximum relative resistance change R rel, max Linear fit R² = drying MWNT content [wt%] very fast electrical response on fiber swelling Higher signal at lower CNT content lower CNT network density at lower CNT content time [s] Pötschke et al. Composites Science and Technology 70 (2010) 2,

20 Example 2: Textile with sensory properties 4. Textiles with CNT containing fibers Example: Weaved textiles with multifilaments containing MWCNTs 80 x 90mm 2 Format ca. A4 Textile made from acrylic yarn as warp thread and multifilaments of conductive PCL + 4 wt% MWCNT / PLA = 50/50 wt% or cotton as weft threads, contact using brass electrodes Composites/Blends: IPF Fibers and textile: Ensait, France Textile made from glass fibers and conductive PLA +4 wt% MWCNTs as weft threads contact using conductive adhesive Composites: IPF, Fibers: Ensait (France) und Uminho (Portugal) Textile: Tissa Glasweberei AG, Switzerland 20

21 5. Tests on textiles with CNT containing fibers Simulation of a leaking fluid (solvent) Example 2: Textile with sensory properties 2 ml solvent put in lines on the textile, 5 cycles relative resistance change R rel [-] Ethylacetate Aceton Rentenberger et al. Sensors and Actuators B, 160 (2011) 1, time t [s] High, fast and reproducible signal different responses to both solvents - Textile made from acrylic yarn as warp thread and multifilaments of conductive PCL + 4 wt% MWCNT / PLA = 50/50 wt% or cotton as weft threads, contact using brass electrodes - Time resolved measurement of the electrical resistance 21

22 Example 2: Textile with sensory properties Possible Applications of sensory textiles in building construction and industrial plants (leakage detection) T. Villmow et al., Materials Today 14 (2011), 7-8, Examples: (A) A piping system, (B) a tank on a truck, (C) a barrel, (D) buildings with flat and slanted roofs, and (E) a waste disposal site. 22

23 Summary and Outlook 1. Basic solutions for effective dispersion of CNTs in thermoplastic polymer matrices are developed to a large extent 2. Material formulations are developed, adaption to special applications/needs possible 3. First succesfull applications of CNT filled composites (e.g. in sport goods, fuel lines with CNT containing PA12,.) 4. Researchers developed examples for further applications, which need to be put into praxis 5. Price of MWCNTs (ca. 100 Euro/kg) still too high for many applications 6. Further application areas are under research, e.g. within INNO.CNT, (see Polymer-CNT composites a material class with future! 23

24 Thanks to partners: Body car panel: Dr. Beate Krause, Dr. Andreas Leuteritz, DP Bernd Kretzschmar Sensory textiles: DI Tobias Villmow, Dr. Rosina Rentenberger, Dr. Andreas John Thanks for your attention More information see:

25 Conference announcement 6th International Conference on Carbon Based Nanocomposites (so far: Carbon Nano Tube (CNT)- Composites) Conference Chairmen: Petra Pötschke, IPFDD (D), Alan H. Windle, University of Cambridge (UK) , Dresden Deadline for abstract submission: May 1st, 2013 See: - Continuation of the conference series Cambridge Hamburg (Prof. Schulte) - Conference every 2 years - This conference aims to gather the international scientific community working in the field of carbon based nanoparticle-polymer composites. At the conference the latest results and findings in this field will be presented and discussed. The conference will offer a great opportunity for delegates to exchange knowledge and make contacts.

26 Book announcement ISBN , ISBN-13: , 2011, 848 pages 26