MFGT 104 Materials and Quality Chap 9: Composites

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MFGT 104Materials and QualityChap 9 Composites
Professor Joe Greene CSU, CHICO
MFGT 104
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Chap 9 Polymers Composites

• Objectives
• Define the components and difference types of
  composites.
• Explain the different types of composite
  construction and the reasons behind them.
• Describe the various manufacturing methods used
  to produce composites.
• List the different reinforcing materials used in
  composites.
• List the various matrix materials used in
  composites.
• Excellent Web sites
• Michigan State http//islnotes.cps.msu.edu/trp/
• U of Delaware http//www.ccm.udel.edu/publications
  /CU/99/
• Cornell University http//www.engr.siu.edu/staff2/
  abrate/NSFATE/links.htm

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Composites

• Composite definition
• A composite is a material comprised of two or
  more physically distinct materials with at least
  one material providing reinforcing properties on
  strength and modulus.
• Natural Composites
• Bone
• Wood
• Bamboo Natures fiber glass due to pronounced
  fibrillar structure which is very apparent when
  fractured.
• Muscle and other tissue
• Engineering Composites
• Reinforced concrete beams
• Thermoset composites Thermoset resins
  (polyurethanes, polesters, epoxies)
• Glass fibers, Carbon fibers, Synthetic fibers,
  metalfibers, or ceramic fibers
• Thermoplastic composites (polypropylene, nylon,
  polyester,TPU,polyimide)
• Glass fibers, Carbon fibers, Synthetic fibers,
  metalfibers, or ceramic fibers

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SMC Sheet Molding Compound
RTM Resin Transfer Molding
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Automotive Plastics and Composites Use

• Exterior Composite Panels
• doors
• Sheet Molded Compound (SMC) Camaro, Firebird and
  Corvette
• Resin Transfer Molding (RTM) Viper
• hoods
• Sheet Molded Compound (SMC) Camaro, Firebird,
  Corvette, Ford trucks
• Resin Transfer Molding (RTM) Viper, Heavy duty
  trucks)
• bumper beams
• Glass Mat Thermoplastic (GMT) Camaro, Firebird,
  Venture, Transport,
• Interior
• floor pan
• Resin Transfer Molding (RTM) Corvette
• Engine
• valve covers, intake manifolds, fluid containers,
  etc.

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Automotive Plastics and Composites Use
SMC Sheet Molding Compound
SMC Sheet Molding Compound
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Recreational Plastics and Composites Use

• Snow Equipment
• skis, snow boards, snow mobiles, etc.
• Water Sports Equipment
• water skis, water crafts, snorkel equipment,
  fishing gear
• diving equipment
• Land Sports Equipment
• shoes, roller blades, skate boards, tennis, golf
• Air Sports Equipment
• plane kits

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Applications for Thermosets

• Epoxy
• Protective coatings maintenance coatings for
  industrial and marine, tank linings, industrial
  floorings, beer and beverage can coatings, food
  cans, appliance primers, hospital and laboratory
  furniture.
• Bonding and adhesives Automotive and aircraft
  industries adhesive to metals and composites.
• Molding, casting and tooling Molding compounds
  in electrical and electronic industries, casting
  resins, potting resins. Prototype and master
  model tools.
• Laminating and composites Binders in fiber
  reinforced laminates and composites. Laminates
  are used in printed wiring boards. Composite
  applications include filament winding (high
  performance pipes in oil fields, pressure
  vessels, tank and rocket motor housings),
  pultrusion, casting, and molding (graphite
  composites for aerospace applications)
• Building and construction Flooring (seamless,
  self-leveling, or epoxy terrazzo floors), repair
  of bridges and roads with glass and carbon fiber
  wraps, concrete crack repair, coat reinforcing
  bars, binders for patios, swimming pool decks,
  and soil around oil-well drills.

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Applications for Thermosets

• Polyester
• Boat hulls, shower stalls, electrical components,
  appliances
• Recreation vehicles, automotive body panels,
  floor pans SMC
• Soft tooling, patterns
• Cultured marble, buttons, corrosion resistant
  tanks and parts,
• Corrugated and flat paneling, simulated wood
  furniture, bowling balls, polymer concrete, and
  coatings
• Polyurethane
• Rigid foams (MDI) Laminated board stock,
  Moldings, Bun, Foam in place insulation, sprayed
  foam, packaging
• Semi-flexible foam (MDI and TDI) Moldings,
  Integral-skin moldings
• Flexible foam(TDI) Moldings, integral skin
  molding, carpet underlay
• Packaging (TDI) Furniture cushioning
• Microcellular foam (MDI) RIM parts, shoe soles
• Non-foam cast elastomers
• Coatings, binders, thermoplastic elastomers,
  sealants, paints

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Composite Classifications

• Reinforcement Type
• Discontinuous (fibers are chopped and dispersed
  in matrix resin)
• Short fibers fiber lengths 3mm or less (most
  injection molded materials)
• Long fibers fiber lengths greater than 6 mm.
  (Some injection molded materials with 6mm fibers,
  Sheet Molding Compound (SMC) with 1 fibers, DFP
  Directed Fiber Preforms for RTM and SRIM)
• Particulates fibers is forms as spheres, plates,
  ellipsoids (some injection molded materials
  reinforced with mineral fibers)
• Continuous (fibers are throughout structure with
  no break points)
• Glass roving glass bundles are wound up in a
  packet similar to yarn.
• Roving is woven into several weaves using a loom
  machine like in apparel.
• Mat products random swirl glass pattern.
• Woven product roving is woven into machine
  direction (warp) and cross direction (weft)
• Uni product roving is woven in one direction
  with a cross thread given to hold mat together.

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Composite Classifications

• Resin (or matrix) type
• Thermoset resins- those that undergo a chemical
  cross-linking reaction
• Epoxy reaction of bisphenol A and
  epichlorohydrin
• Polyester reaction of difunctional acid (or
  anhydride) and a difunctional alcohol (glycol)
• Polyurethane reaction of alcohol and isocyanate
• Phenolic
• Silicone
• Melamine
• Thermoplastic resins- those that are formed under
  heat
• Polyamines (nylon) (short and long fibers)
• Polyesters (short and long fibers)
• Polypropylene (short, long fibers and continuous
  fibers)
• Other thermoplastic resins (short and long
  fibers)

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Processing of Composites

• Open Mold processes
• Hand lay-up
• Spray-up
• Vacuum bag, pressure bag, autoclave
• Filament winding
• Centrifugal casting
• Closed Mold Processes
• Compression molding
• Injection Molding high pressure
• Resin Transfer Molding (RTM), Structural Reaction
  Injection Molding (SRIM) low pressure
• Pultrusion

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Properties of Materials

• Tensile modulus Density Spec Mod
• Low alloy steel 207GPa(30Mpsi) 7.85 g/cc 26spGPa
• Aluminum 72GPa (10Mpsi) 2.8 g/cc 26spGPa
• Carbon fiber 300GPa(40Mpsi) 1.8 g/cc 167spGPa
• Glass fiber 76GPa (10Mpsi) 2.56g/cc 30spGPa
• Aramid fiber 125GPa (20Mpsi) 1.4g/cc 89spGPa
• (Kevlar)
• Tensile strength Density Spec Str
• Low alloy steel 1500MPa(220Kpsi) 7.85
  g/cc 191spMPa
• Aluminum 500MPa(75Kpsi) 2.8 g/cc 178spGPa
• Carbon fiber 2400MPa(360Kpsi) 1.8 g/cc 4320spGPa
• Glass fiber 2000MPa(300Kpsi) 2.56g/cc 781spGPa
• Aramid fiber 3000MPa (450Kpsi) 1.4g/cc 2140spGPa
• (Kevlar)

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Thermosets

• Thermosets are polymers that undergo a chemical
  reaction during the polymerization.
• Thermosetting reaction is not reversible under
  heat.
• Epoxy
• Standard epoxy is based on bisphenol A and
  epichlorohydrin.
• Properties include good adhesion to many
  substrates, low shrinkage, high electrical
  resistivity, good corrosion resistance, and
  thermal.
• Processing is achieved without generation of
  volatiles.

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Polyester and Polyurethane

• Polyester
• Thermoset reaction between a difunctional acid
  (or anhydride) and a difunctional alcohol
  (glycol)
• Heat or radiation can trigger the cross linking
  reaction
• Accelerators (or promoters) speed up the
  reaction.
• Condensation Reaction results in CO2 and H2O.
• Monomer required to polymerize, e.g., Styrene at
  30 to 50 in commercial polyester systems
• Polurethane
• Reaction between isocyanate and alcohol (polyol).
  Condensation Reaction results in CO2 and H2O.
• Crosslinking occurs between isocyanate groups
  (-NCO) and the polyols hydroxyl end-groups (-OH)
• Thermoplastic PU (TPU) have some crosslinking,
  but purely by physical means. These bonds can be
  broken reversibly by raising the materials
  temperature, as in molding or extrusion.

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Polyurethane Chemistry

• Reaction between isocyanate and alcohol (polyol).
• Crosslinking occurs between isocyanate groups
  (-NCO) and the polyols hydroxyl end-groups (-OH)
• Thermoplastic PU (TPU) have some crosslinking,
  but purely by physical means. These bonds can be
  broken reversibly by raising the materials
  temperature, as in molding or extrusion.
• Ratio between the two give a range of properties
  between a flexible foam (some crosslinking) to a
  rigid urethane (high degree of crosslinking).
• In PUR foams density can range from 1 lb/ft3 to
  70 lb/ft3.
• Foams are produced by chemical blowing agents.
• Catalyst are used to initiate reaction.
• RIM process is used to produce fenders and bumper
  covers

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Processing of Composites

• Open Mold processes
• Hand lay-up
• Spray-up
• Vacuum bag, pressure bag, autoclave
• Filament winding
• Centrifugal casting
• Closed Mold Processes
• Compression molding
• Injection Molding high pressure
• Resin Transfer Molding (RTM), Structural Reaction
  Injection Molding (SRIM) low pressure
• Pultrusion

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Processing of Composites

• Open Mold processes
• Hand lay-up and Spray-up
• Filament winding

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Processing of Composites

• Open Mold processes
• Vacuum bag, pressure bag, SCRIMP
• autoclave Apply Vacuum Pressure and Heat in an
  oven which can be 5 feet to 300 feet long

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Thermoset Reacting Polymers

• Process Window
• Temperature and pressure must be set to produce
  chemical reaction without excess flash (too low a
  viscosity), short shot (too high a viscosity),
  degradation (too much heat)

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Processing of Composites

• Closed Mold Processes
• Compression molding moderate pressure
• Injection Molding high pressure
• Resin Transfer Molding (RTM), Structural Reaction
  Injection Molding (SRIM) low pressure
• Pultrusion low pressure

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Injection MoldingGlass Reinforced Composites

• Plastic pellets with glass fibers are melted in
  screw, injected into a cold mold, and then
  ejected.

Glass filled resin pellets
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Composites Have a Fiber Preform

• Fiber type
• Roving form that can be sprayed into a 3-D
  preform
• Roving form that is woven into a glass sheet and
  then formed to shape (preform)

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Compression Molding

• Compression molding was specifically developed
  for replacement of metal components with
  composite parts. The molding process can be
  carried out with either thermosets or
  thermoplastics. However, most applications today
  use thermoset polymers. In fact,compression
  molding is the most common method of processing
  thermosets.

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Resin Transfer Molding

• In the RTM process, dry (i.e.,unimpregnated )
  reinforcement is pre-shaped and oriented into
  skeleton of the actual part known as the preform
  which is inserted into a matched die mold.
• The heated mold is closed and the liquid resin is
  injected
• The part is cured in mold.
• The mold is opened and part is removed from mold.

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Structural RIM

• Fiber preform is placed into mold.
• Polyol and Isocyanate liquids are injected into a
  closed mold and reacted to form a urethane.