1 plastic materials

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1 plastic materials

  1. 1. Plastic Materials The objective of this training session is to familiarize you with the generally used plastic materials , their properties and applications. Objective: Contents: <ul><li>Why plastics? </li></ul><ul><li>What are plastics? </li></ul><ul><li>Classification of polymers </li></ul><ul><li>Classification of thermoplastic materials </li></ul><ul><li>Fillers, Reinforcement fibers & Additives </li></ul><ul><li>Plastic Blends </li></ul><ul><li>Commonly used plastics & their </li></ul><ul><li>properties </li></ul><ul><li>Plastic material selection </li></ul>Take away ... basics about plastic materials
  2. 2. Why Plastics??? - Polymers which are very resistant to chemicals. - Polymers which are thermal and electrical insulators. - Generally, polymers which are light in weight - with varying degrees of strength. - Polymers that can be processed in various ways to produce thin and very intricate parts. Plastic Materials The origin of the word &quot;plastics&quot; comes from Greek. Meaning “to form”
  3. 3. PLASTICS PLASTICS PLASTICS !!! THAT IS WHAT WE HEAR . WHY IS IT SO ??? WEIGHT OF PACKING ENERGY CONSUMPTION WASTE VOLUME 100% +391% +208% +258% WITH PLASTIC MATERIAL WITHOUT PLASTIC MATERIAL Plastic Materials Comparison of plastics as packaging materials
  4. 4. PLASTICS ARE A MERE 4% OF THE USES OF OIL FUELS OTHERS PETROCHEMICALS PLASTICS MISC. 7% 86% 7% 4% 3% Plastic Materials 100Kg Of plastics in a motor car replaces 200 to 300 Kg Of traditional material
  5. 5. Use of Plastics in Western Europe Plastic Materials The consumption of energy reduced by 50% in appliances from past 20 years
  6. 6. Plastics 8% Paper/Cardboard27% Miscellaneous 17% Metals 5% Glass 9% Organic Material 34% Household waste in western Europe (129 million tons/year) 72% 3% 16.8% 8.2% Plastic Materials Recycling is the major advantage in plastics to reduce the waste
  7. 7. Plastic Materials <ul><li>Applications: </li></ul><ul><li>Automotive </li></ul><ul><li>Medical </li></ul><ul><li>Appliances </li></ul><ul><li>Electrical </li></ul><ul><li>Sports </li></ul><ul><li>Advantages: </li></ul><ul><li>Greater design freedom (part complexity) </li></ul><ul><li>Less number of parts </li></ul><ul><li>Fewer assembly operations </li></ul><ul><li>No secondary operations </li></ul><ul><li>Weight reduction </li></ul><ul><li>Cost reduction </li></ul><ul><li>Properties tailored to specific applications </li></ul>What is polymer&polymerization? The principal structure of plastic is that a unit, or mer, is linked many times to become a polymer. The chemical process for the formation of polymers is called as polymerization. <ul><li>Thermoplastic & Thermoset materials </li></ul><ul><li>Crystalline & Amorphous materials </li></ul><ul><li>Natural & Synthetic polymers </li></ul><ul><li>Copolymers </li></ul><ul><li>Alloys </li></ul><ul><li>Elastomers </li></ul>Classification:
  8. 8. • Organic polymeric materials . • Mostly Petrochemical based. • Polymer : Made of many units. – Generally a few thousand to a few million in one molecule. Plastic Materials
  9. 9. Classification of plastic materials Thermoplastics are resins that repeatedly soften when heated and hardened when cooled. Nylon, Acrylic, Acetal, Polystyrene, Polyvinyl chloride, Polyethylene, Cellulose acetate are some examples. Thermoplastic elastomers known as highly elastic and flexible resins. Thermosets(cross-linked plastics) Initially a liquid or a semisolid or a powder, which solidify on heating for first time, and then will only decompose on heating to a high temperature. Phenolic, Amino, Epoxy, Polyurethane are few examples. Vulcanization is process to convert from rubbers to thermoset plastics. Thermoplastics materials are major contribution to engg. applications
  10. 10. <ul><li>The thermal behavior of thermoplastics leads to </li></ul><ul><li>Melt processing techniques such as </li></ul><ul><li>Injection molding - suitable for precision & complex parts </li></ul><ul><li>Extrusion - suitable for single cross section parts </li></ul><ul><li>Thermoforming - suitable for complex big parts </li></ul><ul><li>Blow molding - suitable for bottle shape parts </li></ul><ul><li>Roto molding - suitable for big components like water tanks </li></ul><ul><li>The thermal solidification of thermosets leads to </li></ul><ul><li>Processing methods such as </li></ul><ul><li>Hot compression molding </li></ul><ul><li>Resin transfer molding </li></ul><ul><li>Pultrusion </li></ul><ul><li>Vacuum bagging , pressure bagging </li></ul>Classification of plastic materials Injection molding is the dominated process in plastics...
  11. 11. This is what happens to thermoplastics and thermosets, when we process them. Classification of plastic materials
  12. 12. Classification of plastic materials
  13. 13. Classification of plastic materials
  14. 14. <ul><li>Crystalline Materials : </li></ul><ul><li>the chemical structure allows the polymer </li></ul><ul><li>chains to fold on themselves and pack </li></ul><ul><li>together in an organized manner during </li></ul><ul><li>the melting and cooling process. </li></ul><ul><li>The structure the polymer is uniform and </li></ul><ul><li>Order. </li></ul><ul><li>Opaque material </li></ul><ul><li>Shrinkage is more(around 2%) </li></ul><ul><li>Shrinkage is non-uniform in both direcitons </li></ul><ul><li>Warpage is more </li></ul><ul><li>Sharp transition in the Melting phase </li></ul><ul><li>Very good Chemical resistance </li></ul><ul><li>Low gloss and dimensional stability </li></ul><ul><li>Acetal, Nylon, Polyethylene, Polypropylene, </li></ul><ul><li>Polyamides, Polyester(PET, PBT)Acrylic etc. </li></ul>Classification of thermoplastics <ul><li>Amorphous Materials: </li></ul><ul><li>the chemical structure of the Amorphous materials is random and not in order after the melting and cooling process. </li></ul><ul><li>The structure of the polymer is no-uniform and random. </li></ul><ul><li>Transparent material </li></ul><ul><li>Shrinkage is less (around 0.5%) </li></ul><ul><li>Shrinkage is uniform in both the directions </li></ul><ul><li>Warpage is less </li></ul><ul><li>Gradual transition in the Melting phase </li></ul><ul><li>Low Chemical resistance </li></ul><ul><li>High gloss and dimensional stability </li></ul><ul><li>Polystyrene, ABS, PC, SAN, PVC etc. </li></ul>Liquid crystalline materials are one having amorphous regions between and connecting the crystalline regions
  15. 15. Classification of thermoplastics
  16. 16. Classification of thermoplastics
  17. 17. Classification of thermoplastics
  18. 18. Classification of thermoplastics
  19. 19. Relative polymer properties Liquid crystalline materials are best...
  20. 20. Plastic fillers, Reinforcing fibers & Additives <ul><li>Fillers </li></ul><ul><li>Glass spheres </li></ul><ul><li>Carbon black </li></ul><ul><li>Metal powders </li></ul><ul><li>Silicon sand </li></ul><ul><li>Wood flour </li></ul><ul><li>Ceramic powders </li></ul><ul><li>Mica flakes </li></ul><ul><li>Molybdenum Disulfide </li></ul><ul><li>Reinforcing fibers </li></ul><ul><li>Glass fibers </li></ul><ul><li>Carbon fibers </li></ul><ul><li>Aramid fibers </li></ul><ul><li>Jute </li></ul><ul><li>Nylon fibers </li></ul><ul><li>Polyester fibers </li></ul><ul><li>Additives </li></ul><ul><li>UV Stabilizers </li></ul><ul><li>Plasticizers </li></ul><ul><li>Loubricants </li></ul><ul><li>Colorants </li></ul><ul><li>Flame retardants </li></ul><ul><li>Antioxicants </li></ul><ul><li>Antistatics </li></ul>“ Fillers/Fibers/Additives” maybe any substances that is added to the polymer in small concentration in order to alter their physical properties either to facilitate processing or to change physical, chemical or electrical properties of the material. Fillers/fibers/additives improves the properties by 30-40% <ul><li>Preservatives </li></ul><ul><li>Processing aids </li></ul><ul><li>Fungicides </li></ul><ul><li>Smoke suppressants </li></ul><ul><li>Foaming agents </li></ul><ul><li>Viscosity modifiers </li></ul><ul><li>Impact modifiers </li></ul>
  21. 21. <ul><li>Blends are mechanical mixtures of chemically different polymers or </li></ul><ul><li>co- polymers. </li></ul><ul><li>What is expected of a blend? </li></ul><ul><li>High performance at reasonable price. </li></ul><ul><li>Modification of performance as market develops. </li></ul><ul><li>Extending the performance of expensive resins. </li></ul><ul><li>Generation of unique materials. </li></ul><ul><li>They should be economical, competitive and should not affect other needed properties. </li></ul><ul><li>They should be easy to process. </li></ul>Plastic Blends <ul><li>Most commonly used blends: </li></ul><ul><li>ABS/PVC Blends </li></ul><ul><li>PC/ABS Blends </li></ul><ul><li>PBT/PC Blends </li></ul><ul><li>EPDM/PP </li></ul>Blending of plastics is innovative in the competitive market
  22. 22. Plastic Material Selection <ul><li>Identify application requirements - mechanical (load, impact, stiffness, etc.), thermal (temperature range, maximum use temperature, etc.), environmental considerations </li></ul><ul><li>Identify the chemical environment - define the chemical stress, temperature, contact time and type </li></ul><ul><li>Identify specific loads - regulatory (UL, FDA, etc.), outdoor or UV exposure, light transmission (clear or opaque), fatigue and creep requirements </li></ul><ul><li>Define processing considerations - Injection molding, blow molding, extrusion, thermoforming, foam molding etc. </li></ul><ul><li>Assembly - painting, plating, shielding, adhesion, snap fit, welding etc. </li></ul><ul><li>Finish & gloss </li></ul><ul><li>Cost </li></ul><ul><li>Availability </li></ul>Material section is the key factor in the design phase
  23. 23. Plastic Material Selection <ul><li>Material performance </li></ul><ul><li>Modulus </li></ul><ul><li>Strength/Ductility </li></ul><ul><li>Thermal Conductivity </li></ul><ul><li>Viscosity </li></ul><ul><li>Material Cost </li></ul><ul><li>Part Performance Requirements </li></ul><ul><li>Load/Deflection </li></ul><ul><li>Time/Temperature </li></ul><ul><li>UV Stability, Transparency, </li></ul><ul><li>Chemical Compatibility, etc. </li></ul><ul><li>Part design </li></ul><ul><li>part Stiffness </li></ul><ul><li>Optimal Ribbed Geometry </li></ul><ul><li>Wall Thickness </li></ul><ul><li>Part Volume/Weight </li></ul><ul><li>Manufacturing </li></ul><ul><li>Maximum Flow Length </li></ul><ul><li>Minimum Wall Thickness </li></ul><ul><li>Cycle Time </li></ul><ul><li>Manufacturing Cost </li></ul>Material Selection Goal: Minimize System Cost = (Material Cost) x (Part Volume) + (Machine Cost) x (Cycle Time) Design based material selection
  24. 24. Plastic Material Abbreviation
  25. 25. Common properties of plastic materials <ul><li>Physical properties </li></ul><ul><li>Density </li></ul><ul><li>Specific gravity </li></ul><ul><li>Refractive index </li></ul><ul><li>Water absorption </li></ul><ul><li>Mold shrinkage </li></ul><ul><li>Rheology </li></ul><ul><li>Transparency </li></ul><ul><li>Elasticity </li></ul><ul><li>Plasticity </li></ul><ul><li>Ductility, Toughness </li></ul><ul><li>Brittleness </li></ul><ul><li>Notch sensitivity </li></ul><ul><li>Lubricity </li></ul><ul><li>Coefficient of linear expansion </li></ul><ul><li>Mechanical properties </li></ul><ul><li>Tensile strength </li></ul><ul><li>Flexural Modulus </li></ul><ul><li>Elongation </li></ul><ul><li>Creep </li></ul><ul><li>Impact strength </li></ul><ul><li>Fatigue resistance </li></ul><ul><li>Hardness </li></ul><ul><li>Coefficient of friction </li></ul><ul><li>Electrical properties </li></ul><ul><li>Conductivity </li></ul><ul><li>Volume resistivity </li></ul><ul><li>Surface resistivity </li></ul><ul><li>Dielectric strength </li></ul><ul><li>Arc resistance </li></ul><ul><li>Thermal properties </li></ul><ul><li>Melting point </li></ul><ul><li>Glass transition temp </li></ul><ul><li>Thermal conductivity </li></ul><ul><li>Aging at elevated temp </li></ul><ul><li>Flammability </li></ul><ul><li>Environmental conditions </li></ul><ul><li>Stress level </li></ul><ul><li>Temperature </li></ul><ul><li>Chemical compatibility </li></ul><ul><li>Weathering resistance </li></ul><ul><li>Chemical Properties </li></ul><ul><li>Molecular weight </li></ul><ul><li>Melt viscosity(MFI) </li></ul><ul><li>Glass transition temperature </li></ul><ul><li>Heat distortion temperature(HDT) </li></ul>
  26. 26. Commonly used plastics and properties

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