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Phthalate Plasticizers CE 435 Introduction to PolymersCE 435 Introduction to Polymers Brian AmatoBrian Amato Sarah KarlSarah Karl Carla NgCarla Ng Timeline (history) First Plasticizer 18601930 Phthalates Introduced 1980s DEHP Declared Carcinogenic 2001 IARC Re-classifies DEHP as non- carcinogenic 1998 European Parliament calls for alternatives to phthalates Outline nIntroduction nA Plasticizer Timeline nTheory nWhat are Phthalate Plasticizers (and why do we care)? nThe Plasticizer Market n n Health Health ConcernsConcerns n n Science and Science and Industry Industry ResponseResponse n n Government Government PositionsPositions n n Health or Health or Hype?Hype? n n Conclusions.Conclusions. Introduction nWhat is a plasticizer? nWhere are they commonly found? General Definition nA Plasticizer is a polymer additive. nEffect on polymer properties: an important distinction from other additives. nIncreases polymer flexibility, elongation or workability. Types of Plasticizer (I) nInternal vs. External nInternal plasticization occurs via chemical interactions. nCopolymerization is one type of internal plasticization. nExternal plasticization occurs via physical interactions. nExternal is the most common: cost, ease of processing. Types of Plasticizer (II) nPrimary vs. Secondary nPrimary Plasticizer affects resin properties. nSecondary is a “Plasticizer- plasticizer”: used to increase the effectiveness of the primary plasticizer. Plasticizers In PVC nCling-film for food packaging. nMedical devices: blood bags, IV bags, tubing. nVinyl floors. nSynthetic leather. nElectrical Cables. nToys: teethers for infants and Ernies favorite bath-time companion. Plasticizers All Around Us nNon-PVC Uses nLiquid plasticizers used in coating to protect car chassis. nPaints. nPrinting Inks. nAdhesives. Plasticizer Theory Three Mechanisms: Lubricity Theory Gel Theory Free-Volume Theory Lubricity Theory nAssumes the rigidity of the resin (pure polymer) arises from “intermolecular friction.” nPlasticizer molecules are introduced on heating. nAt room temperature, these molecules act as lubricants for the polymer chains. Gel Theory nResin-resin interactions occur at “centers of attachment.” nPlasticizer molecules break these interactions and masks the centers from each other, preventing re- formation. nThis theory is not sufficient to describe interaction should be combined with Lubricity Theory. Free-Volume Theory nFree volume: “internal space” available in the polymer for the chains to move. nThis volume increases sharply at the glass transition temperature, Tg. nPlasticizer is meant to decrease the glass transition temperature, imparting increased flexibility to polymer at room temperature. Choosing Your Plasticizer nEffectiveness Considerations nHow Much Plasticizer Necessary nInteraction Parameters: Our Friends Flory and Huggins. nApplication Considerations: nTemperature Range nDegree of Flexibility Desired nPhthalates: the #1 Choice for PVC Plasticizer Market nYearly Plasticizer Production nPlasticizers are the largest class of polymer additives produced. nGlobal volume of 10 billion lbs in 1999 n$5 billion value with 2-3% yearly market growth. n1% of Phthalates produced are used in childrens toys. n10% are used in medical applications. Phthalate Plasiticizers nWhat are they Chemically Speaking? A Phthalate ester derived from phthalic acid by an esterification reaction. Mechanism: phthalic acid to phthalate ester H Phthalate Plasiticizers nProperties Colorless Oily liquid ( like vegetable oil) Ester odor High boiling point Inert, and very stable over long periods Phthalate Plasiticizers Types: nDEHP (Di(2-ethylhexyl) phthalate) Structure Phthalate Plasiticizers Properties of DEHP Insoluble in H2o Soluble in mineral oil, hexane, most organic solvents Easily dissolved in bodily fluids, such as saliva and plasma. Boiling point: 386.9oc Density: 0.9732 g/L Molecular weight: 390.5618 g/mol Phthalate Plasiticizers Uses of DEHP: Used in medical devices Toys Pacifiers Vinyl Upholstery Food containers Table cloths Shower curtains Raincoats ( and the list goes on) Phthalate Plasiticizers nDINP (Diisononyl Phthalate) Structure Phthalate Plasiticizers Properties of DINP Insoluble in H2O Soluble in most organic solvents Boiling point: not available Density: not available Molecular weight: 418.6 g/mol Phthalate Plasiticizers Uses of DINP: Replaced DEHP in toys when initially determined to be carcinogenic. Uses of DEHP in Medical Devices qPhthalates (DEHP) in Medical Devices: Blood Storage Bags IV Bags Catheters Dialysis tubing qBenefits: nWhy is DEHP used? Cost efficiency Safety Resists kinking Uses of DEHP in Medical Devices Long shelf life Transparent Withstands high pressures without leaking Withstands both freezing and steam sterilization Collapse when empty, therefore they do not have to be injected with sterile air to replace the blood or fluid being withdrawn. Uses of DEHP in Medical Devices nOther convincing reasons DEHP contributes to the extended storage of red blood cells. Doubles shelf life compared to other plasitcizers. 5-7 billion patient days of exposure without any reported adverse health effects Health Concerns nDEHP is a Carcinogen? Studies in the early 1980s on the effects of DEHP on rodents by U.S National Toxicology Program and International Agency for Research show carcinogenic effect. Scientific papers give rise to concerns of reduced sperm counts from phthalates, due to the endocrine disruption theory. Health Concerns nConcerns Abated: The International Agency for Research on Cancer changes reverses its position on DEHPs Carcinogenic effects. Endocrine disruption theory in regards to DEHP disproved. Health Concerns nResearch with laboratory rats suggests sexual developmental issues by reducing fetal testosterone levels nTestosterone levels were reduced to female levels nHow does this relate to Humans? Or does it? Health Concerns nTests were performed on Monkeys who are primates like humans nDEHP & DINP were both used and yielded no noticeable biological or physical responses to treatment nSpecies specificity? Health Concerns nShould this give manufacturers of Phthalates a clear conscience? Not Necessarily nResearchers in Puerto Rico claim that premature breast development of young girls, thelarche, may be the result of Phthalate exposure n8 out of every 1000 girls suffer from this condition Other Health Concerns Aside From Medical nPlasticizers and Infants: Toys and Teethers nPlasticizers in Food: Packaging Film Industry/Science Response nIn response to concerns about the safety of plasticizers, industry and science worked together to study the effects and disseminate information. nToy manufacturers voluntarily replaced phthalates and, in some cases, PVC. nEuropean Chemical Industry Council (CEFIC) forms EMSG, ECPI. nECPI conducts joint research with Chemical Manufacturers Association (CMA) in the U.S. nThe EPA, the Vinyl Institute and NIH provide information to consumers about their rights and the safety of phthalate-containing products. Government Decisions nEurope nSeveral European nations banned the use of phthalates in toys. nInternational Agency for Research on Cancer classifies DEHP as carcinogenic, then reverses their decision in February of 2000. nAs late as April of this year, the European Parliament calls for the use of substitution products. Seek to eliminate environmental effects of phthalates. Government Decisions nUnited States nThe EPA regulates the amount of DEHP and DINP in the environment. They are listed as toxic chemicals subject to reporting requirements under the Pollution Prevention Act (PPA). nThe FDA has issued no warnings on phthalate plasticizers, and does not consider them to be carcinogenic. No action has been taken by the US government in issues outside of the environmental aspect of phthalates. Any consumer product industry response has been voluntary. Health or Hype? Evaluating the Positions of the Major Players nGreenpeace nHave come out against the Vinyl industry in general, due to their belief in the toxicity of chlorine. nThe Vinyl Institute nSeeks to disseminate information about the importance of vinyl products in our life and the evidence that they are not harmful to humans. Alternatives to Plasicizers qBenzoates qCitrates qDINA qEPZ (Edible Plasticizer) qTXIB Plasticizer (hard oil) q168 Plasticizer qDEHP is still used in medical devices although alternatives are being explored Conclusion nMichael Fumento of the Hudson Institute: “If your child eats toys, phthalates are the least of your worries!” nConflicting evidence about the effects of phthalates in humans and the environment. nPossible consequences for the food chain. nIn the end, it is up to consumers to educate themselves and make informed decisions. References 1./cher/minutes/plast1010 899.html 2./masspirg/enviro/sw/pv c 3.Abbott, Barbara D. (2000). “The Plasticizer Diethylhexyl Phthalate Induces Malformations by Decreasing Fetal Testosterone Synthesis during Sexual Differentiation in the Male Rat.” Toxicological Sciences 58, 339-349 4.Ackley, David C. (2000). “Effects of Di-isononyl Phthalate, Di-2-ethylhexyl Phthalate, and Clofibrate in Cynomologus Monkeys.” Toxicological Sciences 56, 181-188 5.Carraher, Charles E. Polymer Chemistry: an Introduction 4th Ed. (1996) Marcel Dekker, Inc. NY, Ne