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Chem 3/4

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Chem 3/4

  1. 1. PolyVinyl Chloride (PVC) LAM Kwok Tung Kenny(52610985) Ngai Sau Man Carmen (52621860) Lee Wing Man (52569943) Chow Lai Yin Kevin (52621822)
  2. 2. INTRODUCTION
  3. 3. Plastic Molecular unit (Carbon, Hydrogen) repeated and formed chains Man-made “first plastic” :celluloid In1860s’ To replace Ivory
  4. 4. Types of plastic Resin identification code Lots of types of plastic Different molecular unit Different chemical and physical feature♵ PVC
  5. 5. PolyVinyl Chloride (PVC) Molecular unit  Light and High Toughness Colorless Not easy to be corrode by acid or base Fire Retardant Add Plasticizer to change its hardness Vicat softening point : 65- 100
  6. 6. PolyVinyl Chloride (PVC) Cheap Easy to produce Wildly used Add Plasticizer to change its hardness Plastic Wrap, tube…
  7. 7. PVC Production In HongKong Sunny Hose Company Limited In Tai Po Produce Tubes For water supply or sprinkle
  8. 8. MANUFACTURINGPVC(POLYVINYLCHLORIDE) PRODUCT
  9. 9. Processes Cracking and Polymerizatio Molding Chlorination n VCM(Vinyl PVC(PolyvPetroleum chloride inyl Products monomer) chloride)
  10. 10. Cracking and Chlorination Petroleum heated with catalyst, high pressure and without air Produce Ethene and “light” hydrocarbons Chlorination to ethene Thermal cracking Chloroethene Vinyl chloride monomer
  11. 11. Polymerization of PVC Condition : UV light or heat and pressure Organic peroxide compounds(initiator) Monomer(VCM) Addition polymerization Free radical addition
  12. 12. Mechanism Chain initiation : Chain propagation : Chain termination :
  13. 13. Polymerization of PVC Molecule masses vary with the temperature Exothermic reaction Strong intermolecular force Dipole-dipole between polymer chains
  14. 14. Adding additive Plasticizer(塑化劑) DEHP(di-2-ethyl hexyl phthalate) Filler Stabilizer Dyes or coloring C6H4(C8H17COO)2 Bis(2- ethylhexyl)phthalate(BEHP)
  15. 15. Molding Using heat to soft the plastic, pressure to squeeze and place to a mold, then cool down Injection molding(a) Compression molding(b) a b
  16. 16. Beyond your imagination !!!DANGER OF PVC
  17. 17. Environment & human Wholeproduct life cycle: production use  disposalProduction: Releases of EDC and VCM carcinogensduring process; Release of heavy distillate material
  18. 18. Use: Release of toxicants in PVC productsDisposal: landfill cause leachates incinerated generate dioxin
  19. 19. Productionvinyl chloride monomer (VCM) & ethylene dichloride (EDC) are by-products of PVCOn human: highly volatile VCM jeopardise workers’ health ( risk of liver / brain cancer) colourless EDC , inhalation/ direct contact may have toxic effect
  20. 20.  VCM & EDC are genotoxic  cause irreversible damage to DNA (e.g. Birth defects/ genetic diseases of descendants) On environment:  improper treatment of VCM & EDC or other by-products contaminate (underground)water and sediment (e.g. alluvial soil)Case study:In Japan, consumption on rice irrigated by
  21. 21. Use the use of PVC products threaten human healthOn human: PVC additives phthalate plasticizers increase risk of asthma PVC flooring  persistent wheezing, pneumonia, prolonged cough… etc metal stabilizers (e.g. lead) leach into potable water
  22. 22. Disposal discarded PVC materials are hazardousOn human: phthalates and metals leach out of disposed products into landfill leachate groundwater contamination accidental PVC fire  permanent respiratory disease fire release dioxin  reproductive disorders, immune suppression
  23. 23. On environment: burning of chloride (major component of PVC) during combustion of incinerationRelease of toxic dioxin regarded as persistent organic pollutants (POPs), dioxin accumulate in atmosphere recycling of PVC is extremely difficult

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