Phthalate Plasticizers CE 435 Introduction to Polymers Brian

Phthalate Plasticizers CE 435 Introduction to Polymers Brian Amato Sarah Karl Carla Ng

Timeline (history) First Phthalates Plasticizer Introduced 1860 1930 European IARC Re-classifies Parliament calls DEHP as nonfor alternatives Declared carcinogenic to phthalates Carcinogenic 1980’s 1998 2001

Outline Introduction n A Plasticizer Timeline n Theory n What are Phthalate Plasticizers n (and why do we care)? n The Plasticizer Market n. Health Concerns n. Science and Industry Response n. Government Positions n. Health or Hype? n. Conclusions.

Introduction n What is a plasticizer? n Where are they commonly found?

General Definition Plasticizer is a polymer additive. n Effect on polymer properties: an important distinction from other additives. n Increases polymer flexibility, elongation or workability. n. A

Types of Plasticizer (I) n Internal vs. External n Internal plasticization occurs via chemical interactions. n Copolymerization is one type of internal plasticization. n External plasticization occurs via physical interactions. n External is the most common: cost, ease of processing.

Types of Plasticizer (II) n Primary vs. Secondary n Primary Plasticizer affects resin properties. n Secondary is a “Plasticizer-plasticizer”: used to increase the effectiveness of the primary plasticizer.

Plasticizers In PVC n n n Cling-film for food packaging. Medical devices: blood bags, IV bags, tubing. Vinyl floors. Synthetic leather. Electrical Cables. n Toys: teethers for infants and Ernie’s favorite bath-time companion.

Plasticizers All Around Us n Non-PVC n Liquid Uses plasticizers used in coating to protect car chassis. n Paints. n Printing Inks. n Adhesives.

Plasticizer Theory Three Mechanisms: Lubricity Theory • Gel Theory • Free-Volume Theory •

Lubricity Theory n Assumes the rigidity of the resin (pure polymer) arises from “intermolecular friction. ” n Plasticizer molecules are introduced on heating. n At room temperature, these molecules act as lubricants for the polymer chains.

Gel Theory n Resin-resin interactions occur at “centers of attachment. ” n Plasticizer molecules break these interactions and masks the centers from each other, preventing re-formation. n This theory is not sufficient to describe interaction– should be combined with Lubricity Theory.

Free-Volume Theory n Free volume: “internal space” available in the polymer for the chains to move. n This volume increases sharply at the glass transition temperature, Tg. n Plasticizer is meant to decrease the glass transition temperature, imparting increased flexibility to polymer at room temperature.

Choosing Your Plasticizer n Effectiveness Considerations n How Much Plasticizer Necessary n Interaction Parameters: Our Friends Flory and Huggins. n Application Considerations: n Temperature Range n Degree of Flexibility Desired n Phthalates: the #1 Choice for PVC

Plasticizer Market n Yearly Plasticizer Production n Plasticizers are the largest class of polymer additives produced. Global volume of 10 billion lbs in 1999 $5 billion value with 2 -3% yearly market growth. <1% of Phthalates produced are used in children’s toys. n 10% are used in medical applications. n

Phthalate Plasiticizers n What are they Chemically Speaking? ØA Phthalate ester derived from phthalic acid by an esterification reaction. Ø Mechanism: phthalic acid to phthalate ester H

Phthalate Plasiticizers n Properties Ø Colorless Ø Oily liquid ( like vegetable oil) Ø Ester odor Ø High boiling point Ø Inert, and very stable over long periods

Phthalate Plasiticizers Ø Types: n DEHP (Di(2 -ethylhexyl) phthalate) Ø Structure

Phthalate Plasiticizers Ø Properties ü Insoluble of DEHP in H 2 o ü Soluble in mineral oil, hexane, most organic solvents ü Easily dissolved in bodily fluids, such as saliva and plasma. ü Boiling point: 386. 9 oc ü Density: 0. 9732 g/L ü Molecular weight: 390. 5618 g/mol

Phthalate Plasiticizers Ø Uses of DEHP: ü Used in medical devices ü Toys ü Pacifiers ü Vinyl Upholstery ü Food containers ü Table cloths ü Shower curtains ü Raincoats ( and the list goes on……. . )

Phthalate Plasiticizers n DINP (Diisononyl Phthalate) Ø Structure

Phthalate Plasiticizers Ø Properties ü Insoluble of DINP in H 2 O ü Soluble in most organic solvents ü Boiling point: not available ü Density: not available ü Molecular weight: 418. 6 g/mol

Phthalate Plasiticizers Ø Uses of DINP: ü Replaced DEHP in toys when initially determined to be carcinogenic.

Uses of DEHP in Medical Devices q Phthalates (DEHP) in Ø Blood Storage Bags Ø IV Bags Ø Catheters Ø Dialysis tubing q Benefits: n Why is DEHP used? Ø Ø Ø Cost efficiency Safety Resists kinking Medical Devices:

Uses of DEHP in Medical Devices Ø Long shelf life Ø Transparent Ø Withstands high pressures without leaking Ø Withstands both freezing and steam sterilization Ø 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 n Other convincing reasons Ø DEHP contributes to the extended storage of red blood cells. Ø Doubles shelf life compared to other plasitcizers. Ø 5 -7 billion patient days of exposure without any reported adverse health effects

Health Concerns n DEHP is a Carcinogen? Ø Ø Studies in the early 1980’s 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 n Concerns Ø The Abated: International Agency for Research on Cancer changes reverses its position on DEHPs Carcinogenic effects. Ø Endocrine disruption theory in regards to DEHP disproved.

Health Concerns n Research with laboratory rats suggests sexual developmental issues by reducing fetal testosterone levels n Testosterone levels were reduced to female levels n How does this relate to Humans? Or does it?

Health Concerns n Tests were performed on Monkeys who are primates like humans n DEHP & DINP were both used and yielded no noticeable biological or physical responses to treatment n Species specificity?

Health Concerns Should this give manufacturers of Phthalates a clear conscience? Not Necessarily n Researchers in Puerto Rico claim that premature breast development of young girls, thelarche, may be the result of Phthalate exposure n 8 out of every 1000 girls suffer from this condition n

Other Health Concerns Aside From Medical n Plasticizers Ø Toys and Teethers n Plasticizers Ø and Infants: in Food: Packaging Film

Industry/Science Response n In response to concerns about the safety of plasticizers, industry and science worked together to study the effects and disseminate information. n n Toy manufacturers voluntarily replaced phthalates and, in some cases, PVC. European Chemical Industry Council (CEFIC) forms EMSG, ECPI conducts joint research with Chemical Manufacturer’s Association (CMA) in the U. S. The EPA, the Vinyl Institute and NIH provide information to consumers about their rights and the safety of phthalate-containing products.

Government Decisions n Europe n n n Several European nations banned the use of phthalates in toys. International Agency for Research on Cancer classifies DEHP as carcinogenic, then reverses their decision in February of 2000. As 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 n United States n n The 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). The 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 n Greenpeace n n Have come out against the Vinyl industry in general, due to their belief in the toxicity of chlorine. The Vinyl Institute n Seeks 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 q Benzoates q Citrates q DINA q EPZ (Edible Plasticizer) q TXIB Plasticizer (hard oil) q 168 Plasticizer q DEHP is still used in medical devices although alternatives are being explored

Conclusion Michael Fumento of the Hudson Institute: “If your child eats toys, phthalates are the least of your worries!” n Conflicting evidence about the effects of phthalates in humans and the environment. n Possible consequences for the food chain. n In the end, it is up to consumers to educate themselves and make informed decisions. n

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