Recent Advances in Thermoplastic Composites Dr. Sriram K GE Global - - PowerPoint PPT Presentation

John F Welch Technology Centre, Bangalore

Recent Advances in Thermoplastic Composites

• Dr. Sriram K

GE Global Research Bangalore

Global Research SABIC Innovative Plastics Programme

Thermoplastics Market

AMORPHOUS SEMICRYSTALLINE COMMODITIES ENGINEERING PLASTICS HIGH PERFORMANCE PLASTICS

PVC PS HIPS Polyethylene Polypropylene ABS PC PMMA POM PET

PEI PSU LCP PPS

PC blends PPE / PS blends PBT PBT blends PA PA blends

GE Polymers

PEEK

Tg, Heat Stability, Processing temperature and Cost Global Research SABIC Innovative Plastics Programme

ATC’s - Advanced Thermoplastic Composites

Chopped Fibres GMT LFT

Glass mat Thermoplastics Long Fibre Thermoplastics

ATC’s

Specialty polymers reinforced with Carbon, Aramid fibres and/or Sandwiched with cores

5 mm 10 mm

Continuous Fibre Length Process Injection Moulding Compression, Pultrusion, Autoclave Vf (%) Modulus (GPa)

5 15 25 200 70 % 50 % 30 % 15 %

Thermoplastic Composites

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Advanced Thermoplastic Composites Nanocomposites

Thermoplastics Composites

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Why is this so challenging?

• Many thousands of small diameter

fibres,

• packed very closely together,
• to be impregnated with very viscous,

complex liquids.

impregnating resin

Advanced Thermoplastic Composites

Advantages of Thermoplastics over Thermosets

Recycleability High Toughness Drapability Low cycle time Online repair / re-shaping and Weldability No toxic gas emission during processing No shelf life for resin

Challenges

Fibre-matrix Adhesion/Impregnation High temperature processing High viscosity High Residual Stresses Global Research SABIC Innovative Plastics Programme

Polymer Mix Glass Creels Pultrusion Block Wet Bath Puller Pelletizer Finishing/ Packaging

Pultrusion Process

Thermoplastic Pultrusion Force Rungs Glass Strand

LGF Vf = 30 – 70 %

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Long Fibres vs. Short Fibres

• Fiber length retention provides skeletal matrix
• Critical to high impact/modulus relationship
• Standard pellet length = 11mm
• Typical fiber lengths in molded parts = 6mm+

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Continuous fibre Composites Composite Structural Part

Powder coated fabric Prepreg Commingled Fabric Stacked Laminate Yarn

Polymers Melt Processin g Reactive Processin g Monomers

Powder

Time

Polymerisatio n

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In-mold Polymerized Thermoplastic Composites

PBT PC PEEK PPS Source: K.van Rijswijk et. al. Composites Part A, V38, 2007. Global Research SABIC Innovative Plastics Programme

Carbon-fiber prepreg tapes impregnated with CBT resin could be used as a reinforcing wrap for

• lder concrete

structures such as

• bridges. The

thermoplastic tape can be heated and bent around corners.

In-mold Polymerized Thermoplastic Composites

Wind-turbine blades and automotive composites are some

• f the applications

being actively investigated for new in-mold polymerized PBT resins. These thermoplastic composites would be recyclable.

• Processing advantages over thermosets materials

No toxic generation, High productivity, Mechanicals, durability and environmental advantages of thermoplastics

• Solid low viscosity oligomers – 75 % Carbon fiber fiber

loading

• Masterbatches for thermoplastics
• Continuous fiber prepregs
• Nanocomposites-dispersion exfoliation
• Smart fillers – conducting, self-healing.

Global Research SABIC Innovative Plastics Programme

• Fibre movement during low

viscosity stage of the resin.

• Reduces compressive and

hot/wet properties of composites

• Develops due to the anisotropic

properties of the constituents.

Process Related Issues Residual Stress Fibre misalignment

Matrix Fibre

Unidirectional Composite Thermal Expansion E-glass af = +4.9 × 10-6 K-1 Polycarbonate am = +60 to 70 × 10-6 K-1

Residual Stresses

Prestressed fibres Uncured matrix Matrix tensile residual stress Compressive stress Fibre/matrix adhesion 1 2 3 Prestressed fibres Uncured matrix Matrix tensile residual stress Compressive stress Fibre/matrix adhesion 1 2 3

Fibre Prestressing Methodology

• 800
• 600
• 400
• 200

200 400 600

• 20

20 40 60 80 100 120 140 160 Prestress (MPa) Residual strain (µε) EFPI Middle EFPI 40 mm from edge ERSG Middle ERSG 40 mm from edge FBG Middle

Source: Sriram K et. al. SAMPE, 2005. Global Research SABIC Innovative Plastics Programme

Sandwich Structures

Manufacturing Fibre/Polymer Tape Shaping to Laminates Producing exterior and interior face sheets Structural Panel Honeycomb Core Foam Core Design and Mechanical Testing

Thermoplastic Honeycomb cores ABS - for rigidity, impact strength, toughness, surface hardness and dimensional stability Polycarbonate - for UV-stability, excellent light transmission, good heat resistance properties Polypropylene - for good chemical resistance Polyethylene - a general-purpose low-cost core material Global Research SABIC Innovative Plastics Programme

25 50 75 100 2005 2010 2015 2020 Plastics Compounds (B lbs.)

Plastics Nano

Nanocomposites

% Nano composites

0.3 % 0.6 % 2.2 % 9.8 %

Source: Freedonia Nano Composites Source: Bodo Fiedler et. al. CST, V66, 2006 Richard A Vaia and Daniel Wagner; Materials Today Nov. 2004

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Macro vs Nano: Interface

Value Proposition for Nanocomposites

Mechanical Barrier Heat Release Rate

Nexans’ plenum cable jacketing, the first such product in the U.S. Sud- Chemie’s nanoclay in polyolefin cable jacket

FR

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Materials Science and Engineering 28 (2000) 1. Source: Polymer, V47, Iss.8, 2006

The Processing Challenge

Global Research SABIC Innovative Plastics Programme 5% Nanoclay / Polystyrene

Surface treatment of Nanoclay Exfoliation

8µm particle > 3000 platelets Chemistry Processing Chemistry/Processing Dispersed Tactoids/ Intercalants Partial Dispersion Dispersed Tactoids/ Intercalants

Key Challenge in Nanocomposites is Dispersion

8µm particle > 3000 platelets Chemistry Processing Chemistry/Processing Dispersed Tactoids/ Intercalants Partial Dispersion Dispersed Tactoids/ Intercalants

Key Challenge in Nanocomposites is Dispersion

Major Challenges Ahead….

• Compatibility of surface

chemistry to matrix

• High Temperature stability of

surface modifier

• Repeatability in the plant

scale

Treated with Methacryloethoxyhexadecyl dimethyl ammonium bromide (MHAB) Source: http://www.chbmeng.ohio- state.edu

Time

Millimetre Micro Nano Thermosets Thermoplastics Bio-Polymers

Environmental Friendly

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Acknowledgements

• Dr. Sanjay Charati
• Dr. Gautam Chatterjee
• Dr. Soumyadeb Ghosh

Global Research SABIC Innovative Plastics Programme