Chem 3/4


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  • Over time, these additives leach out of vinyl products. Phthalates are typically present in indoor air at much higher concentrations than outdoor air due to their high concentrations in consumer products and building materials.
  • 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)
    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
    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