Laboratory-Mixers & Extruders

Transcription

1 Laboratory-Mixers & Extruders for Nanocomposite Application Dr.Ing. A. Frendel / Dipl.Ing. M.Jährling

2 Content Nanocomposites Instruments (PI) Mixer Twin Screw Extruder MiniLab and MiniJet References Source: German Wikipedia, original upload 29. Dez 2004 by APPER 2

3 Comparison of Dimensions Finger nail: If Nano Clay platelets would be this size, conventional fillers compare to: 18 beach ball: Talc / Lime stone particle 1,5m diameter, 1km long tube: Glass Fiber 3

4 Nanotechnology There is plenty of room at the bottom (Feynmann, 1959) Nanotechnology [greek. νανος, dwarf] is structuring or production of materials in dimensions less than 100 nm. In this scale surface effects play a predominant role. More molecules are on the surface than inside the particles. Nanocomposites are matrix materials such as rubber, engineering plastics or polyolefines with a small content of nanoscale materials. Usually less than 5% of nanomaterials are used to improve thermal or mechanical properties Typical ways to produce Nanocomposites are In-Situ-Polymerization and melt blending / compounding Three types of nano material are commonly melt blended with plastics: Nano clay, nano tubes and nano scale particles (SiO 2, ZrO 2, Ag) 4

5 Nanotechnology Typical nano fillers: Nano scale particles, like SiO 2, TiO 2, Al 2 O 3, ZrO 2, Ag, nano diamonds Carbon nano fibers, carbon nano tubes Nano clays Typical applications: Improving mechanical properties Increasing the electrical conductivity Increasing thermal conductivity Biocide / antibacterial UV-absorption 5

6 Nanoclay Nanoclay (Silicate platelets, 1nm thick and 70 to 150 nm across) is most commonly used, and commercially available as masterbatch or surface modified powder Nanoclay improves barrier properties of film against gas and liquids Task for the compounding is to achieve good distribution of the clay sheets (exfoliation) Helsinki University of Technology, Department of the Chemical Technology 6

7 Schematic illustration and terminology of nano composites formed with organo clays Melt Compounding Tactoid Intercalated Intercalated, disordererd Exfoliated, delaminated 7

8 Material Characterization, Processing Instruments: Our selection for melt blending of nano composites PolyLab OS Twinscrew Compounder Mini-Compounder Moduar Torque Rheometer with measuring mixers and measuring extruders for development of new compounds Twinscrew Compounder for developement and Pilotplant (100 g to 200 kg/h) Mini-Compounder and Mini-Injection Moulding for smallest amounts of material, app. 5 g 8

9 PolyLab OS Laboratory Mixers Single screw Extruder Twin screw Extruder 9

10 RheoDrive + Mixer/Extruder Sensor = PolyLab OS RheoDrive Mixer sensors Single screw extruder sensors additional analyzing sensors Twin screw extruder sensor Rotors Feeding Screws Dies Postex systems 10

11 11 PolyLab OS Flexible Design

12 12 PolyLab OS Flexible Design

13 Laboratory Mixers - measuring principle Shearing of a test sample in a heated mixing chamber with counter rotating rotors 3 2 Test results: Ł Torque Ł Melt temperature 13

14 Mixer - Rheogram Temperature Torque Energy 14

15 PolySoft evaluation Curve Type 1 Example 1: used to determine exfoliation of monmorillonite Torque [Nm] 5% organoclay [1] L M Runtime t [min] Materials: Polyolefins: PE, PP Engineering / high performance Plastics: (PS, PA, PC, PEEK, LCP ) Compounds of a.m. polymers with organo clays, nano tubes Point detection: L = Loading point M = Minimum point (steady state torque) Observe the melting behaviour and flowability of a compound We have noted that a simple indicator of the extent of clay exfoliation within polyethylene is the steady-state torque recorded during melt compounding 1. [1]Ref.: Influence of clay exfoliation on the physical properties of montmorillonite/polyethylene composites T.G. Gopakumar, J.A. Lee, M. Kontopoulou*, J.S. Parent Polymer 43 (2002)

16 PolyLab OS PolySoft Mixer PolySoft Mixer SW: - Job stream structure analog Haake RheoWin - The user is guided through the measurement - Project handling: several tests can be saved in a project 16

17 PIM: Critical (powder) loading of feedstock The erratic reading in the steps for increased powder load show the limiting powder [%] in the mixture. Add powder Contact free and fast, high resolution torque sensors have a big advantage over old style dynamometer where the reaction of a heavy motor is measured, the erratic reading, here key feature is damped or smoothed Ref. LR45-e, Joseph A. Krudys, ThermoHaake

18 Nanoscale Ceramic Al 3 O 2 Powders for PIM (Mixer Example 2) Juliane Kraus (Ref.) describes in detail how to optimize a binder system in a Torque Rheometer system (R600, roller rotors). Type modifier (better: lower torque with stearic acid amide) Minimum content of this modifier (Torque depends only on [%]powder) batches in a larger scale are produced for the complete PIM process. stearic ac. 8 % stearic ac. amide 9% stearic ac. amide Torque 10% stearic ac. amide 24 [%] 27 [%] [%] powder Ref. (in german): Juliane Kraus Spritzgießen nanoskaliger keramischer Pulver am Beispiel des Degussa Aluminiumoxid C Hochschulschrift: Saarbrücken, Univ., Diss.,

19 Nanoclay with Elastomers Mixer Example 3 Various Composites of organo clays and Elastomers are investigeated by F. Schön, Univ Freiburg, the mixing was done in the HAAKE Rubber mixer 610. The organo clay composites are compared to standard silica composites Parameters: CR and SBR composites mixing for 10 min set Temperature 80 variable speed to stay below 90. At 7 min start of crosslinking started by adding of vulcanization chemicals. EPDM Composites were mixed at 130 C and grafted EP-g-MAA Composites at 100 C Practical example: Identical organoclays but from different suppliers were compounded. For same reinforcement (tensile stress) 2,3% (supplier A) and 6,2% (supplier B) organoclay were needed. Ref.: (dt.) Elastomer / Schichtsilikat Komposite: Einfluss der Füllstoffstruktur auf mechanische, dynamische und Gasbarriere-Eigenschaften, Frank Schön Dissertation, Universität Freiburg (2004) 19

20 Electrical Conductivity Measurement A new approach by combining traditional methods with new technologies Ram 2 Control Thermocouple 3 Rotors 4 Conductivity Sensor 4 20

21 Rheomex Extruder Application Extruders are generally used to: transport material plasticize compress homogenize compound vent chemical reaction building up pressure Measure viscosity 21

22 Principle of Twin-screw extruders Co-rotating Counter-rotatingrotating 22

23 Twin Screw Extruder: Co- or Counter rotating? Counter-rotating rotating Rheomex Twinscrew Extruders: - Defined residence time (good for i.e. rigid PVC) - High shearing (good for dispersion of Nano fillers) - Self cleaning - No controlled feeding needed - High pressure build up Co-rotating Rheomex Twinscrew Extruders: - Mixing of shear sensitive material (i.e. Polyolefins Binder) - Compounding and Venting - Controlled shearing - most flexible (screw design, barrel ports and length) - Controlled feeding necessary - Wear resistance as option 23

24 24 Rheomex CTW100

25 Screws for Rheomex PTW OS Segmented, with slip-on elements, allowing variable configuration Screw diameter: 16 /24 mm Co rotating, intermeshing, self cleaning screws High volume design Screw shafts: Design: hexagonal Material: Heat treated, wear reduced 25

26 Parallel twin-screw extruder - Screw Elements: Conveying elements: Profiles with open chambers are used: - in the feeding sections - for melt exchange (longitudinal mixing) - for degassing (venting) Profiles with closed chambers are used: - for high pressure built up - in front of kneading elements 26

27 Parallel twin-screw extruder - Screw Elements: Mixing Elements : Mixing Elements are used to introduce shear energy to the extruded materials. The disks are arranged in different offset angles used for: - plasticizing - shearing - mixing - dispersing 27

28 28 Mixing elements

29 Parallel twin-screw extruder - Screw Elements: Distributive Flow Elements : Distributive Flow Elements are special mixing elements, used for the distribution of small quantities of additives and shear sensitive materials. The shearing energy introduced to the polymer is significantly lower than that of the kneading elements. 29

30 30 Screw elements: Rheomex PTW16

31 Rheomex PTW16 flexible screw configuration 31

32 Screw configuration (Standard Layout 75%) Feed Screw Mixing Element Conveying sample only partly filled low shear Melting & mixing completely filled high shear 32

33 Dispersive and Distributive mixing For nearly all mixing applications a well dispersed and well distributed mixture is required. Distributive mixing can be achieved by splitting and reorienting the flow repeatedly Dispersive mixing can be achieved by passing the mixture through small regions of intense deformation. Mixing and composites, M. Kontopoulous Chee p. 390presentation Queens University 33

34 Maximum flexibility... Feed ports Length Screw design Split Barrel 34

35 PTW16 OS - Maximum flexibility... Split Barrel 35

36 36 PTW16 OS - Maximum flexibility

37 New PTW16 XL for PolyLab OS Horizontal split, with a lift-off top to be opened for ease of cleaning, simple removal of the screws and visualisation of the melting process. The segmented top barrel part is built with 4D modules to be easily reconfigured by the user. Barrel segments are available for cooling, feeding solids, liquids and for venting. Optional extension unit 15D (easy to bolt on by the user!) to run a 40D extruder e.g. for reactive extrusion. 37

38 Example Nano Ceramics for µpim (1) Also for ceramic materials nano materials are of interest. Smallest parts produced by micro injection moulding require fine particles to fill the cavities. The feedstock production is described in detail in the lab report LR56e and the relevant PIM presentation. This is material production for Micro PIM parts (right) Ref.: Picture: ARC Seibersdorf research center Micro PIM part For the HAAKE PolyLab OS a RD16, a PTW16/25 XL parallel twin screw extruder and two HAAKE metering feeder (binder, ceramic powder) was used to homogenize the raw materials (85/15 % wt/wt).the product was cooled on the conveyor belt, easily cut to pellets and manually fed to the MiniJet for specimen production. 38

39 Example Nano Ceramics for µpim (2) Instrument setup, RD16, PTW16/25, split feed with two metering feeders, die plate and conveyor belt. A polyethylene wax based binder was blended with Zirconium oxide. Separate Feed of wax and powder. Can reduce wear for production Output 6 kg/hr 39

40 Use of EVA as compatibilizer in LDPE/organoclay composites 1 Two kinds of polymer/montmorillonite (MMT) intercalated nanocomposites were prepared by melt intercalation under a twin screw extruder (PRISM TES 16 TC, UK). Low density polyethylene [...] can intercalate into the layers spaces of org-mmt (a kind of montmorillonite which was organically modified by cetyltrimethylammonium bromide through ion exchange reaction), especially when adding a kind of compatiblizer, i.e. ethylene vinyl acetate copolymer (EVA[...]). It is well accepted that LDPE is a non-polar polymer and can not intercalate into MMT layers easily because of the poor compatibility between them. [...] Incorporation of EVA, a polar polymer, into these system will acts as a compatibilizer and will improve the interaction between polymer and modifiers. As a result the polymers intercalate into MMT layers more easily. [1] The Dynamic Viscoelasticity of Polyethylene Based Montmorillonite Intercalated nanocomposites Hong Mei YANG, Qiang ZHENG* Department of Polymer Science and Engineering, Zhejiang University Hangzhou Chinese Chemical Letters Vol. 15, No. 1, pp 74 76,

41 Compounding easy data view (Example 3) High speed compounding, Output up to 30kg/hr Optimizing torque and temperature Heat cool view gives an easy overview 41

42 Compounding MMT/ABS with PTW24 and R600OS the results are good because an intra space gallery of 3 nanometres is an evidence that good intercalation has been achieved; prior to compounding the space was 2 nanometres. And also there are some areas where it is possible to see that exfoliation has happened. This results was achieved with a commercial MMT, functionalised for PA, not for ABS (producers are now less available to optimise their products for little amounts). So this is another evidence, in my opinion the compounding is good because we reached the best result possible with the materials available in the market. ~30Å 42 ABS/5 w/ommt I.30P

43 PTW16-40 OS optimizing melt temperature PP, PP-g-MSA, nano clay Tm = 208,1 Tm = 206,1 Tm = 202,4 Tm = 201,0 Tm = 199,8 43 LR-61 nanocomposites - example on compounding of naoclay in twinscrew extruders, D. Hauch A. Wunsch A. Frendel, Thermo Scientific, Karlsruhe 2007

44 PA and Nanoclay with PTW24-40 OS LR-61 Nanocomposites - example on compounding of nanoclay in twin screw extruders, D. Hauch A. Wunsch A. Frendel, Thermo Scientific, Karlsruhe

45 MiniLab Micro Rheology Compounder Right from the introduction of the MiniLab our customers in the nano material research recognized this small extruder as ideal instrument for their material development. More than 10 sets in the North American market are used for research on Nanocomposites. Eastman Kodak published patents on modified clear Polymers. 45

46 MiniLab Micro Rheology Compounder 46

47 MiniLab Micro Rheology Compounder (principle sketch) Saving your Material: The HAAKE MiniLab combines Batch Mixer, Extruder and Rheometer p2 p1 Backflow channel with rheological slit capillary die Bypass valve Output channel 47

48 New barrel design The new MiniLab improves the handling and accessibility for cleaning, a slit die is built in. Optional sensor ports available! Horizontal Split barrel, fast analysis of material Easy cleaning of the outlet channel Build in slit die Improved hardness, no TiN coating necessary 48

49 MiniLab (Example 1): Counter Rotating Screws Intermeshing counter rotating screws are most effective to improve results melt extrusion of multi wall carbon nanotube composites. Due to higher shear agglomerates are well distributed. Degradation of Stabilized PMMA and MWNT was not observed (1). (1) R.E. Gorga, R.E. Cohan, (MIT), Toughness enhancements in PMMA by MWNT, Journal of Polymer Sci (2004) 49

50 MiniLab (Example 1): Counter Rotating Screws SEM images of the surface of the axial cross section for 3 wt % SWNT in PMMA using (a) DACA co-rotating, (b) Haake co-rotating, and (c) Haake counter-rotating screw configurations. (d) A schematic of the cleaved section and the imaging surface Toughness Enhancements in Poly(methyl methacrylate) by Addition of Oriented Multiwall Carbon Nanotubes, Journal of Polymer Sci (2004) RUSSELL E. GORGA, ROBERT E. COHEN Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts

51 MiniLab (Example 2) combining results Meltflow MT + MiniLab (nano tubes) Jody Ericsson found a linear correlation of % of nano tubes with the decreasing MI value of Polypropylene blend. The viscosity was measured in the MiniLab Ref.: INCORPORATING CARBON NANOTUBES INTO POLYPROPYLENE FIBERS, JODY ERICKSON Master Thesis 2003, North Carolina State University 51

52 Nano Compounder MiniLab II Nano Compounder MiniLab II with counter-rotating screws and manual feeder MiniLab Nano Compounding bundle ( ) consists of: MiniLab with co-rotating screws Set of counter-rotating screws with adjustment tool and gears ( ) Manual feeding device for HAAKE MiniLab ( ) Features: - MiniLab with hardened barrel (58 HRC) and hardened screws (50 HRC) to reduce wear and contamination with highly abrasive Nano tubes - Both screw options (co- and counter rotating screws) to enhance flexibility - Counter rotating screws for best dispersive mixing of Nano tubes - Counter rotating screws for stable volume feeding the re-circulating channel to allow Rheometry in the slit die - Co-rotating screws to compound thoroughly even shear sensitive materials 52

53 Features MiniLab II - Summary: Stable horizontal design: Easy cleaning, easy handling Backflow channel with slit capillary: Absolute shear stress measurement Rheological characterization of the sample during mixing process Pneumatic feeding device: Controlled, reproducible feeding procedure Additional measuring ports possible: Option for additional sensors like UV, NIR, Option for counter-rotation screws: for high shear and rheology application N2-purge for feeder and extruder: To avoid thermo-oxidative degradation of the sample Pneumatic ByPass Valve 53

54 HAAKE MiniJet Numerical controlled 2 Temperatures controlled Pressure controlled (0.1 bar) Procedure controlled 1. Injection pressure & duration, 2. Post pressure & duration All parameter can be stored Language: English, German Units: bar, psi - C, F, K Improved handling No pressing lever necessary Easy filling of pellet samples Increased performance Same injection pressure form 40% less feeding pressure 54

55 HAAKE MiniJet vertical alignment Specifications: Melt temperature 400 C Mould temperature 250 C Injection pressure Electrical power 1200 bar 230V / 110V Max air pressure Dimensions 10 bar 300x460x kg 55

56 HAAKE MiniJet Micro Injection Moulding The reservoir can be connected with the Minilab to fill in the melt Or direct fill in of pellets into the reservoir chamber 56

57 HAAKE MiniJet Micro Injection Moulding Specific mould design depending on your task for instance Tensile testing specimen Customized moulds e.g. for tablets for bioavailability studies 57

58 HAAKE MiniJet Moulds 58

59 References C.R.P. Dr. Laura Martinelli Use PolyLab with Mixer and PTW24 University of Kentucky Dr. Rodney Andrews & Dr. Eric Grulke Use PolyLab with Mixer and CTW100 Conical Twin & MIT Dr. Robert Cohen nanotechnology for soldiers MiniLab North Carolina State Univ Dr. Russell Gorga uses MiniLab Clemson University Dr. Stephen Foulger & Dr. Amod Ogale uses MiniLab & RheoMix mixers & Haake Rheometers National Research Council of Canada 2 MiniLab s for nano research McGill Univ Dr. Milan Maric 59

60 Question everything 60