Functional polymers

2011

VTT Technical Research Centre of Finland

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Contents of the presentation

Need and approach

Functional plastics’ value chain

VTT’s focus areas on plastics R&D

Plastics processing

Characterization and analysis

Research projects, recent & ongoing

Some research examples

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Need and Approach

Plastics with optimized performance profile are needed. At every turn stricter legislation set its demands for advanced materials.

Functional features need to be integrated into plastic parts and structures. Joining and structuring of plastics with other materials and electronics is one challenge.Processing as well as environmentally friendly plastic compound recipes need continuousdevelopment.

Approaches to overtake the demands for future materials are;

Safe utilization of nanotechnology in powder chemistry, mixing and thermoplasticprocessing.Combination of new processing methods (e.g. direct write, laser activation and MID) withtraditional methods (film making, extrusion, injection molding and overmolding).Application driven functional properties to plastics.

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Value Chain

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VTT’s focus areas in plastics R&D

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VTT’s focus areas in plastics R&D

Plastic nanocompoundsEnhanced performance of plasticsEnergy efficiency and environmental sustainability

Joining of plastics and embedded intelligenceThermal management and adhesion Integrated structuresBarrier films and encapsulation

Polymers with active functionalityActuatorsSensors

Plastics processingPerformanceFeasiblity

Example of a good dispersion in polyethylenenanocompound, 3D AFM image.

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Plastic nanocompounds

Technical approachHighly conductive (electrical and thermal) compounds for energy applicationsDielectric compounds for electrical applicationGas and vapour barriersOptimize the overall performance profile of traditionally highly filled plastics e.g. fire retardance, UV-resistance and/or mechanical propertiesSustained functionality even after recycling steps alongthe material’s life cycle

Scientific interest▪ Compatibilization of nanoparticles for polymer▪ Favourable dispersion of the nanoparticles▪ Nanoparticle-matrice interfacial phenomena

AFM images of pure PP (above) and PP with 4% silica nanofiller (below)

z-scale 20 nm

z-scale 100 nm

2 µm

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Joining of plastics and embedded intelligence

Modifying and designing plastics for printed electronicshttp://www.vtt.fi/research/technology/printed_functionality.jsp

Thermal managementMatching thermal expansionHeat conduction

AdhesionJoining plastic parts to semiconductor, ceramic and metal materials

Plastics and electronics integratedCarefully tested methods and parameters

Barrier films and encapsulationHigh requirements for barrier properties in OLED applicationsOvermoulding of printed electronics

Injection moulded parts with integrated OLED-functionality.

Printed OLED-display, integrated to plastic part by overmoulding.

VTT-skrapa,made by overmouldingprinted electronics.

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Polymers with active functionality

Sensors and actuatorsMedical actuators

Materials for electromechanical stimulationControlled shape memory and actuation

Electromechanical plastic filmsThermally more durable plastics nanocompounds

Electroactive elastomersStretchable electrodesActuator concepts

Controlled release▪ Core shell structured composite particles

SEM micrograph of PP/CaCO3 film

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Plastics Processing

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Plastics processing

Micro-scale melt processingSmall Scale ProcessingPilot Scale ProcessingInjection MouldingExtrusionPre- and Post-processing

Collin(30 x 25D) blown film extruderInjection mouldingThermo-Haake MiniLabMicro Compounder

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Micro-scale melt processingThermo-Haake MiniLab Micro Compounder

speed range 1 ... 360 rpm torque max. 5 Nm / screwextruder design conical, co-rotatingpressure up to 200 bartemperature max 350 Cvolume 5,5 ccm

Picture. MiniJet injection moulding machine (on the left). MiniLab Micro Compounder (on the right)

Picture. Moulds from left to right; Tensile testing bar, Impact strenght testing bar, DMA flexulartesting bar, DEA (Dielectric analysis) testing bar, DMA tensiletesting bar and Thermal conductivity testing bar.

Thermo-Haake MiniJet Injection Moulding Machine

<5 g micro-batch processing and injection moldingto produce micro test samples

Temperatures Cylinder max 400 °CMould max 250 °C (no cooling)

Injection Pressure up to 1200 barInjection time and post pressure time are adjustable

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Small Scale Processing

Brabender Plasti-Corder PL 2100-6 mixerSmall size, high temperature and large measuring head

(W50 EHT and W350 EHT, respectively)Extrusion head (single-screw Extrusiongraph 19/25 D), four dies, belt take offCounter rotating twin-screw compounder head (DSK 42/6).

Batch mixersTwo-roll mill, laboratory size,Banbury mixer, 2-3 l,Papenmeier high speed mixer, 5 l,Different size ball mills for minerals,

metals and polymers.

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Pilot Scale Processing

Pilot production (up to 100 kg)

Co-rotating twin-screw compounder Berstorff ZE 25 x 48 Dwith gravimetric feeders, liquid feeding pump, vacuum, water bath, pelletizers (strand cutter) and grinder

Co-rotating twin-screw compounder Berstorff ZE 25 x 33 Dwith gravimetric feeders, forced feeder, liquid feeding pump, vacuum, water bath, air cooling possibility and pelletizer

Co-rotating twin-screw compounder Werner & Pfleiderer ZSK 40 F32,5Ewith gravimetric feeders, forced feeder, 20 mm side feed extruder, liquid feeding pump, vacuum, water cooled metal belt conveyor and pelletizer. Up to 50 kg/h (current screw profile only 20 kg/h).

Dry material mixingForberg mixer40 l with pin mills,Moisture control and additives to fibres,Mixing time 0,5-2 min.

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Injection Moulding

Engel ES 200/50 HL50 tons clamping force25 mm screwcontrol unit CC100instrumented mould having interchangeable inserts (according to ISO standards)

Demag Ergotech 100/420-120 EL Exis S100 tons clamping force22 mm screwmaximum injection speed 1000 mm/s

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Extrusion

Films, Coatings and Profiles

Dolci extruder300 mm wide sheet preform3-layer film (A – B – A)N2-rinsing possibilityChemical and physical foamingDry or water bath coolingExtrusion coating on cardboard

Brabender extruder100 mm and 120 mm wide sheets preform and roundstripMasterbatch productionMax 400 °C4 screw geometries with different compression Clean room possibility

Collin(30 x 25D) blown film extruderOne layerMax 280 °C

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Pre- and Post-processingDrying

Convection ovensDehumidifying dryersVacuum dryingFreeze-drying

MillingHosakawa Alpine

Separating mill 100 g – 30 kg/h,Particle size 0,5 - 10μm,Powder grading.

Orientation MD-streching unit

Modified stretching interval On-line streching from extrusion line

Biaxial laboratory stretcher Brückner (KARO IV)Computer control and force measurement Speed 0,5 - 40 m/min

AC-Corona film treatmentAtmospheric Plasma treatment unit

Bruckner sheet stretching machine

Air plasma nozzle

Film MD-orientation and calibration line

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Characterization and Analysis

SEM image of a PP film with nanostructured POSS®-chemical

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Characterising and Analysing Availability

Mechanical testing• Tensile testing (with oven)• Impact strength, Charpy• DMA Dynamic mechanical analysis

Material properties• DSC Differential scanning calorimetry• TGA Thermogravimetry• Melt Flow Tester (Indexer)• DEA Dielectric analyser• Capillary rheometer• X-ray diffraction

Microscopy and particle size analysis• SEM (with low vacuum mode)• AFM• Optical microscopy• Particle size distribution analyser

Spectroscopy• FTIR (micro-ATR)• UV / VIS 4000,0 3200 2400 2000 1600 1200 800 500,0

0,0

10

20

30

40

50

60

70

80

90

100,0

cm-1

%T

FTIR curve of a polyethylene sample

SEM image of polyamide with glass fibre

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Research Project Examples

High Frequency Circuit Board Laminates

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Research Projects, recent & ongoing:examples

Jointly funded national projectsELCOMPO Electroactive polymer nanocomposites and their actuator applicationsNANOCOM Novel methods to formulate polymer nanocomposites and tailor their dielectric bahaviourEKOALUSTAT Ecological thermoplastic circuit boardsSHIFUNK Novel approaches for fire retardant applications by nanofunctionalization

EU funded collaborative projects (VTT coordinating)MINANO New high-quality mined nanomaterials mass produced for plastic and wood-plastic compositesDURASMART Durable cellular polymer films with giant electromechanical response for smarttransducer applications

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Research example 1: Electrically conductive plastic hybrids

NeedElectrically conductive plasticsImproved conductivityLow cost utilizing inexpensive matrix polymers

Development stepsA concept of a hybrid conductive nanofiller consisting carbonnanotubes (CNT) and inherently conductive polymer, such as polyaniline (PANi).Chemical synthesis of CNT-PANi hybrid with non -covalent lingakeand controllable CNT/PANi concentrations.Exploitation of low molecular weight dispersing agents withmolecular recognition capability with PANi.Compounding with PP.

ResultsHigh conductive injection moulded parts, > 10 S/cmFormation of a continuous biphasic morphology with highconductivie minority phase (conductive pathways)Conductivity fulfils the needs of EMI shielding

Contact: Dr. Juha Sarlinemail: juha.sarlin@vtt.fiTel: +358 20 722 3542

SEM images of a pure CNT sample (higher) and a Pani-CNT hybrid (lower).

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Research example 2: Polymer nanocompounds for HV-insulation

NeedBetter reliability in high-voltage insulation.Less insulation material to reduce weight and cost.Better dielectric performance for passive HV-electronicscomponents.

Development stepsChemical functionalization of inorganic nanofiller particles.Plastics processing in clean room environment

CompoundingExtrusionFilm making

CharacterizationDielectric analysis and mechanical testing

ResultsPure homogeneous polymer nanocompounds. Improved electrical strenght, higher dielectric constant and lowerdielectric losses.

Contact: Mikko Karttunen email: mikko.karttunen@vtt.fiTel: +358 20 722 3544

Dielectric nanocomposite. 60 nm inorganicparticles in polypropylene matrix.VTT & Nanoscience Center at JyU

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Research example 3: Integrating polymer with ceramics and metals

NeedFuture applications of in plastics embedded electronics call new extendedcompatibility between plastics and non-organic components.Dissipative components, such as LEDs, create strong, usually spotlike, thermal loads causing local melting, thermal degradation, stressescreated by thermal expansion, delamination, etc.Film technology (In Mould Labeling) as a technical platform set new needs for adhesion.New demands to construct low cost 3D structures with electronics and optoelectronics.

Development stepsDeveloping of stable and well processable plastic compounds withmoderate thermal conductivity.Developing modification methods to enchance adhesion.Methods to use multilayer flexible film technology and to controll spatialdeformations.

ResultsModerate thermal conductivity may realize a large variety of practicalapplications

Contact: Dr. Juha Sarlinemail: juha.sarlin@vtt.fiTel: +358 20 722 3542

Integration of printed electronics and opticsby over molding of thermoplastic for a touchscreen application.

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Research example 4: Filled impact resistant plastic for low temperatures

NeedHigh stiffness and impactresistance combined with the chemical properties of polyolefins.

Development stepsConventional mineral filled compounds with different compatibilizers and surface treatments.Radically new process where dry materials were bonded to each others by mechanical treatment.

Notched Charpy impact strenght of PE + 20 % talc compounds.

0 10 20 30 40 50 60 70

unfilled PE-HD frombag

PE + talc, normalcompound

PE + simultaneouslymilled PE/talc blend

-20 °C, [kJ/m2]

RT [kJ/m2]

ResultsThe results indicates that mechanical milling of talc and polyethylene together has a significant effect on impact strength, particularly under freezing temperatures. Compared to the corresponding conventional mixture the impact strength at -20C was over triplicate and compared to unfilled polyethylene over twofold.

Contact: Hannu Minkkinenemail: hannu.minkkinen@vtt.fiTel: +358 20 722 3549

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Selected Publications

Thermal, Mechanical and Dielectric Properties of Nanostructured Epoxy-Polyhedral OligomericSilsesquioxane Composites; Takala, Markus; Karttunen, Mikko; Pelto, Jani; Salovaara, Pauliina; Munter, Tony; Honkanen, Mari; Auletta, Tommaso; Kannus, Kari; IEEE Transactions on Dielectrics and Electrical Insulation. Vol. 15 (2008) No: 5, 1224 – 1235Injection moulding of graphite composite bipolar plates, Müller, A.; Kauranen, Pertti; Ganski, A. von; Hell, B., Journal of Power Sources . Vol. 154 (2006) No: 2, 467 - 471Electrically conductive metal polymer nanocomposites for electronics applications, Karttunen, Mikko; Ruuskanen, Pekka; Pitkänen, Ville; Albers, Willem M., Journal of Electronic Materials. Vol. 37 (2008) No: 7 , 951 - 954 Polymer nanocomposite development for electronic industry needs, Koskinen, Jari; Karttunen, Mikko; Paajanen, Mika; Sarlin, Juha, Solid State Phenomena. Vol. 151 (2009), 3 – 9Advanced injection molding mold and molding process for improvement of weld line strengthsand isotropy of glass fiber filled aromatic polyester LCP, Koponen, Matti; Enqvist, Jouni; Nguyen-Chung, Tham; Mennig, Günter, Polymer Engineering & Science. Vol. 48 (2008) No: 4, 711 - 716 Novel heat durable electromechanical film: processing for electromechanical and electretapplications, Saarimäki, Eetta; Paajanen, Mika; Savijärvi, Ann-Mari; Minkkinen, Hannu; Wegener, M.; Voronina, O.; Schulze, R.; Wirges, W.; Gerhard-Multhaupt, R., IEEE transactionson dielectrics and electrical insulation. Vol. 13 (2006) No: 5, 963 - 972

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Selected patentsElectrically conductive elastomer mixture, method for its manufacture, and use thereof; Vilkman, Taisto; Karttunen, Mikko; Wikström, Lisa, Pat. EP1837884, publication date 26 Sept.. 2007 A1, application date 21 March 2007 (2007), Polymer blend and method of preparing same; Vilkman, Taisto; Mustonen, Jenni; Minkkinen, Hannu; Karttunen, Mikko; Pat. US 7,148,281 B2, publication date 12 Dec. 2006 (application number 10/678,073, application date 6 Oct. 2003) (2006) Method of producing a porous plastic film, and plastic film; Karttunen, Mikko; Kortet, Satu; Paajanen, Mika; Pat. EP1680461 A1, publication date 19 July 2006, application number EP04798261, application date 4 Nov. 2004, priority FI 20031607 (2006)Method of producing a porous plastic film, and plastic film; Karttunen, Mikko; Kortet, Satu; Paajanen, Mika; Pat. WO2005044902 A1, publication date 19 May 2005, application number FI04000652, application date 4 Nov. 2004, priority FI 20031607 (2005) Electrically conductive thermoplastic elastomer composite; Albers, Martin; Karttunen, Mikko; Vilkman, Taisto; Pat. US 6875375 B2, publication date 5 April 2005, application number 10806382, priority US 20040178392, 16 Sept. 2004 (2005)Electrically conductive thermoplastic elastomer and product made thereof; Karttunen, Mikko; Mustonen, Jenni; Pat. US 6638488 B2, publication date 28 Oct. 2003, application number US 09/944 408, application date 4 Sept. 2001, priority US 2002/0043654 A1 Apr. 18, 2002 (2003) Tasomainen huokoinen komposiittirakenne ( Planar porous composite structure and method for itsmanufacture). Pat. FI 97114, publication date 25.10.1996 (application number 906234, application date13.12.1990); Suokas, Esa; Karttunen, Mikko. Patentti- ja rekisterihallitus PRH. Helsinki (1996)Menetelmä ja materiaali virtauskanavien, kuten putkien, korjaamiseksi ( METHOD FOR REPAIRING FLOW CONDUITS, SUCH AS PIPE LINES) . Pat. FI. 88646; Karttunen, Mikko; Suokas, Esa; Mäkelä, S.; Järvinen, S. VTT. Espoo (1993) Materiaali virtauskanavien, kuten putkien korjaamiseksi ja materiaalin käyttö (Material for repair of flowchannels, such as piping, and application of the material); Karttunen, Mikko; Suokas, Esa; Mäkelä, Seppo; Järvinen, Seppo; Pat. FI92570, publication date 24.5.1992 (application number 905783, application date23.11.1990) (1992)

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Expected results and exploitation

The most potential benefits that are foreseen in commercial polymer products utilizing nanoscale compounding in polymer matrix with improved process parameters are:

- Lower additive loadings helping to improve sustainability of the processes and enabling better mechanical properties in polymer based materials.

- Sustained functionality even after recycling steps due to the durable inorganic functional nanoparticles, which provide overall energy savings during the entire life cycle of the material.

- Novel polymer functionalities may be combined with other material functionalities for example advantageous material surface, which has sophisticated wear resistant and antifouling properties.

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VTT’s competence, strategy & mission

Advanced Materials -knowledge center has well equipped laboratory facilities and skilled personnel to carry out top level scientific research and demanding customerassignments.

International co-operation withcustomers and research partnersworldwide is one of the key priorities in VTT’s strategy.

VTT’s mission is to produce research and innovation services that enhance the international competitiveness of companies, society and other customers.

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VTT creates business from technology