ENVIRONMENTAL ISSUES

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ENVIRONMENTAL ISSUES
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OUTLINE

• Problem statement
• Global look at the problem
• Solid waste problem
• Possible solutions to solid waste problem
• Green design
• A success story

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Facts and Myths

• A world without plastics and composites!
• Unfair bad reputation
• Potential to do better

http//www.epa.gov/epaoswer/non-hw/muncpl/facts.ht
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Environmental loads by manufacturing sector
EPA 2001, DOE 2001
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Waste Definitions

• WASTE
• WASTE CLASSIFICATION
• SOLID WASTE
• Metals
• Plastics
• Paper
• Hybrid Materials
• .

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What are the choices?

• Recycling (Physical and/or Chemical)
• Waste to Energy Incineration
• Land filling
• Degradation

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Recycling Techniques

• Primary Conversion of waste into materials
  having similar properties
• Secondary Conversion of waste into materials
  having inferior properties
• Tertiary Conversion of waste into chemicals and
  fuels
• Quaternary Conversion of waste into energy

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Types of Plastic Recycling

• Chemical Recycling
• The depolymerization of certain condensation or
  addition polymers back to monomers
• Mechanical Recycling
• The direct recycling and conversion of plastics
  from discarded materials into a reusable form

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Factors Impeding Reclaiming

• Collection
• Heterogeneous in Nature
• Different Plastics
• Different Brands
• Non-plastic Contaminants
• Metals
• Pigments and Dyes
• Label Materials
• Adhesives
• Additives
• Filler/Reinforcements
• Low Economic Value

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Chemical Recycling

• Chemicals can be used for feedstock use or fuel
• Problems with chemical recycling
• Greater accumulation of air and water pollution
• Some regenerated monomers are pollutants
• By-products can be pollutants
• Requires considerable amount of thermal and
  chemical energy to break apart and then more to
  repolymerize
• Currently there are no chemical recycling plants,
  everything is experimental

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Chemical Tertiary Recycling

• Hydrolysis
• Alcoholysis
• Hydrogentation
• Pyrolysis

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Chemical Quaternary
Astrom, Manufacturing of Polymer Composites,
Chapman Hall1997
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Mechanical Recycling

• Most economical and common type of plastic
  recycling in the U.S.
• Currently 1,677 companies handle and reclaim
  plastics
• Steps to mechanical recycling
• Collection
• Sorting
• Reclamation

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Collection

• Commingled or sorted collection
• Curbside or drop-off recycling program
• 63 of nation total has access to recycling
  program
• Currently the amount of some plastics being
  collected falls short of the capacity of the
  recycling facilities

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Material Recovery Facility

• Two functions
• Separating materials
• Prepare materials for the market
• Material is tipped on to the receiving floor
• Pushed by front end loader on to the feeder
  conveyor
• Elevated to presort station
• Overhead magnetic separation stage
• Density separator
• Manually sorted
• Stored in bunkers until bailed

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Material Reclaiming Facility

• Sorted plastics are converted into pellets or
  flakes
• Shredded
• Contaminant removal
• Air classifier
• Float/sink tank
• Washed
• Dried
• Granulated
• 2nd air classifier
• Made into pellets by extrusion or boxed for
  market as flakes

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Green Thinking

• Reduce waste at source
• Increase reuse and recycling
• Recover energy
• Dispose of unavoidable waste safely

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Design for Waste Minimization

• Use less raw material
• Use less virgin material
• Design for equal lifetime of components in an
  assembly
• Design for transportation
• Design for damage tolerance and repair
• Design for afterlife potential

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Design for Recycling

• Design for disassembly
• Label components
• Use few combination of materials
• Design the labels appropriately (same material)
• Avoid painting and adhesive joining
• Minimize number of metal fasteners
• Exclude undesirable melt-reactive combinations
• Avoid non-Separable Colorants

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Story of PET
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Why PET Recycling?

• 8 (volume ) of this solid waste is PET and
  HDPE
• Almost 50 of all plastic bottles are made from
  PET
• PET is convenient to recycle
• Cost effective
• Collection .07/lb.
• Reprocessing .30/lb.
• Total Cost of recycled PET (flake) .37/lb.
• (pellet) .46/lb.
• Cost of virgin PET .62/lb.
• Savings of .25- .16/lb.

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Recycled PET

• May be reused between 25 and 40 times
• Intrinsic viscosity decreases by .02-.03 dl/g
  every time it is re-extruded
• Can be compounded to produce a wider range of
  properties, products, and markets
• Alloying polycarbonate (PC) with recycled PET can
  produce an injectionmoldable compound, done by
  GM for bumpers and body panel material
  (50-60PET/ 40-50 PC) and is 25-30 less
  expensive

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Virgin vs. Recycled PET Uses
Recycled PET Uses
Virgin PET Uses
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Fiber Market

• Used to make fiberfill which is put in pillows,
  sleeping bags, ski-jackets, insulation, shoulder
  pads, etc.
• An IV of .58-.65dl/g is adequate
• Requires a very clean recycled PET,
• cannot use the green recycled PET
• Used to make geotextiles
• stabilizers in railroad beds and paved roads
• can use the green PET because they are usually
  pigmented with carbon black
• Used as continuous filament or yarn in such
  things as carpet face yarns, or woven carpet
  backing
• Used to make insulation that is as energy
  efficient as fiberglass insulation material
• Replacing wood fiber
• longer life and less maintenance

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Strapping Market

• PET strapping replaces metal strapping used in
  pallet wrapping
• made by an extrusion process
• requires high IV
• Mixed with virgin PET or solid stated to increase
  IV

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Sheeting Market

• Used in blister packaging clamshell packages,
  cups, food trays, egg cartons, cassette cases,
  etc
• Needs a high IV
• Making foamed sheets for insulation
• uses the green recycled PET with an additive to
  raise the normally low melt viscosity
• same insulation properties as foamed polystyrene
  but with superior cost/performance qualities

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Some Hope

• Each Problem Has at Least One Solution
• Some Solutions are Demonstrated Commercially
• There is a Price to Pay for the Solution
• There Are Some Success Stories