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Polyethylene

Polyethylene. Allison Payne Bryan Margaria Jenna Haschets Sam Raybuck. Introduction . Linear polymer shape Created in 1933 by accident Largest by volume in the world One of the first materials to sell over a billion pounds a year Several grades available

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Polyethylene

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  1. Polyethylene Allison Payne Bryan Margaria Jenna Haschets Sam Raybuck

  2. Introduction Linear polymer shape Created in 1933 by accident Largest by volume in the world One of the first materials to sell over a billion pounds a year Several grades available Many advantages of using polyethylene One of the most commonly used materials

  3. Why use Polyethylene?

  4. Easy to Process Virgin Material Regrind • No special equipment needed • Non-hygroscopic material • Self purges • Thermally stable • 20% acceptable • Used 6-7 times • Good property retention

  5. Additives, Fillers, Plasticizers • Degradable additives added so plastic wears away after 6 months with heat and sunlight • Flame retardant additives are used to help with flammability • Lubricants reduce melt viscosity for better flow • Color is easily added for decorative purposes • UV absorbers and stabilizers protect against sun damage • Calcium Carbonate, mica, and talc strengthen PE • Plasticizers, like phthalates, can be used for softening material

  6. Recyclable Easy to recycle Cost Range • Available in bailed or loose scrap • Purged and regrind • Sorted, mixed, & clear colors • HDPE • natural post consumer$.57-$.62 • Mixed colors $.44-$.48 • Post industrial $.47-$.52

  7. High Chemical Resistance Why? • Molecular structure • High degree of impermeability • Alkanes (consists of Carbon & Hydrogen) • Non-oxidizing acids • Water soluble solutions Common Uses • House hold containers • Food packaging • Water and gas pipes • Automotive applications

  8. Low Cost Costs Discounts • HDPE $.90-$.92 • LDPE $1.03-$1.05 • Buying in bulk is cheaper • Railcar • Hopper trucks $.02 increase • Box trucks $.05 increase

  9. Toughness At low temperatures • Flexible • Ductile • Ultimate tensile elongation 200-900% depending on grade • Tensile Modulus 11,000 psi- 150,000 psi

  10. Low Density Ranges from .91-.97 g/cm3 • Less than the density of water so it floats • Used in water applications • Pontoon boats • Floating docks

  11. Other advantages • Low water absorption • Gas impermeability • Clarity of thin films • Easy assembly pipe fixtures • Sterilized medical components • FDA approved milk jugs and food storage bags

  12. Wide Range of Uses

  13. Uses HDPE • Tupperware • Chemical Bottles • Milk Jugs • Fuel Tanks • Plastic Bags • Water and Gas pipes • Snowboard Boxes/Rails

  14. Uses LDPE • Food Storage Containers • Six Pack Rings • Welded Parts • Corrosion Resistant Work Surfaces

  15. Uses LLDPE • Plastic Stretch Wrap • Toys • Buckets • Lids • Cable Covers

  16. Uses UHMWPE • Fiber applications • Bullet proof vests • Bow strings • Fishing line • Medical Components • Joint replacement • Hip, knee and spine implants • Sports • Ski bases • Hockey sticks

  17. Why not Polyester? • Longer cycle times • Less chemical resistance • Less dimensionally stable So out of style!

  18. Why not Polypropylene? • Not FDA approved for common uses • Oxidizes more easily • Not as ductile or flexible • More surface static

  19. Why not Nylon? • High water absorption • Poor creep strength • Harder to process

  20. Questions? LLDPEUHMWPE

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