PolymersPolymers

PolymersPolymers PA StandardsPA Standards

• 3.4.12.A: Physical Science, 3.4.12.A: Physical Science, Chemistry, and PhysicsChemistry, and Physics

• 3.2.12.B: Inquiry and Design3.2.12.B: Inquiry and Design• 4.8.12.C: Humans and the 4.8.12.C: Humans and the

EnvironmentEnvironment

“ “Paper or Plastic?”Paper or Plastic?”

Apply concepts about the Apply concepts about the structure and properties structure and properties of matter.of matter.

Evaluate experimental Evaluate experimental information for information for appropriateness and appropriateness and adherence to relevant adherence to relevant science processes.science processes.

Analyze how pollution has Analyze how pollution has changed in quality, changed in quality, variety and toxicity as the variety and toxicity as the United States developed United States developed its industrial base.its industrial base.

Key QuestionsKey Questions

What is a Polymer?What is a Polymer? What does a polymer look like on the What does a polymer look like on the

molecular level? molecular level? What are the characteristics of What are the characteristics of

polymers?polymers?

What is a Polymer?What is a Polymer?

History and Significance of History and Significance of PolymersPolymers

What is a polymer?What is a polymer?• A A polymerpolymer is something made is something made

of many units (ex. chain)of many units (ex. chain)• Each link is a Each link is a monomermonomer (“mer”) (“mer”)

or basic unitor basic unit Made of carbon, hydrogen, oxygen, Made of carbon, hydrogen, oxygen,

and/or siliconand/or silicon

• To make a chain, many “mers”, To make a chain, many “mers”, or links, are hooked, or or links, are hooked, or polymerizedpolymerized, together, together

History and Significance of History and Significance of PolymersPolymers

ExamplesExamples• NaturalNatural

Tar, tortoise shells, horns, tree saps that Tar, tortoise shells, horns, tree saps that produce amber and latexproduce amber and latex

Can be processed with heat and pressure Can be processed with heat and pressure Chemically altered beginning in the 1800sChemically altered beginning in the 1800s

• Vulcanized rubber, gun cotton, celluloidVulcanized rubber, gun cotton, celluloid

• SyntheticSynthetic First synthetic polymer produced was First synthetic polymer produced was

Bakelite in 1909Bakelite in 1909 First semi-synthetic fiber, rayon, developed in First semi-synthetic fiber, rayon, developed in

19111911 World War II cut off availability of natural World War II cut off availability of natural

sources of latex, wool, silksources of latex, wool, silk• Nylon, acrylic, neoprene, polyethylene, etc. Nylon, acrylic, neoprene, polyethylene, etc.

began to be usedbegan to be used

What does a polymer look What does a polymer look like on the molecular level?like on the molecular level?

The Structure of PolymersThe Structure of Polymers Composed of Composed of hydrocarbonshydrocarbons

• Carbon makes up the backbone of the moleculeCarbon makes up the backbone of the molecule• Hydrogen atoms bonded along backboneHydrogen atoms bonded along backbone• Simplest polymer structure is polyethyleneSimplest polymer structure is polyethylene

Polymers may only have carbon and Polymers may only have carbon and

hydrogenhydrogen• Ex. Polypropylene, polybutylene, polystyrene, and Ex. Polypropylene, polybutylene, polystyrene, and

polymethylpentenepolymethylpentene

The Structure of PolymersThe Structure of Polymers

Oxygen, chlorine, fluorine, nitrogen, Oxygen, chlorine, fluorine, nitrogen, silicon, phosphorous, and sulfur may also silicon, phosphorous, and sulfur may also be found in a polymerbe found in a polymer• Polyvinyl chloride (PVC) – chlorinePolyvinyl chloride (PVC) – chlorine• Nylon – nitrogen and oxygen Nylon – nitrogen and oxygen • Teflon – fluorine Teflon – fluorine • Polyesters and polycarbonates – oxygen Polyesters and polycarbonates – oxygen • Vulcanized rubber and thiokol – sulfurVulcanized rubber and thiokol – sulfur

May also have silicon or phosphorous May also have silicon or phosphorous backbone (inorganic polymer)backbone (inorganic polymer)• Ex. Silly PuttyEx. Silly PuttyTMTM is silicon based is silicon based

PolymerizationPolymerization

Addition PolymerizationAddition Polymerization • Ex. polyethyleneEx. polyethylene

1. 1. InitiationInitiation – “mers” begin to bond together – “mers” begin to bond together• a promoter or catalyst may be needed to start or a promoter or catalyst may be needed to start or

speed up a reactionspeed up a reaction 2. 2. PropagationPropagation – continued addition of monomers – continued addition of monomers

into chainsinto chains 3. 3. TerminationTermination – all monomers are used and the – all monomers are used and the

reaction ceasesreaction ceases Condensation PolymerizationCondensation Polymerization

• Ex. nylon, polyesters, urea, formaldehydeEx. nylon, polyesters, urea, formaldehyde As monomers join, a small molecule is eliminatedAs monomers join, a small molecule is eliminated

Molecular StructureMolecular Structure Molecular Structure:Molecular Structure:

Molecular StructureMolecular Structure

Example:Example:• Propylene is the monomer of Propylene is the monomer of

polypropylenepolypropylene• 90-95 percent of all polypropylene 90-95 percent of all polypropylene

polymers have this configurationpolymers have this configuration

Molecular Arrangement of Molecular Arrangement of PolymersPolymers

Amorphous ArrangementAmorphous Arrangement• No long-range order or form No long-range order or form

(think of how spaghetti noodles look on a plate)(think of how spaghetti noodles look on a plate)

• Generally TransparentGenerally Transparent Food wrap, Plexiglass, headlights, contact lensesFood wrap, Plexiglass, headlights, contact lenses

• Low melting pointsLow melting points Crystalline ArrangementCrystalline Arrangement

• Distinct pattern; higher degree of crystallinity, Distinct pattern; higher degree of crystallinity, the less light can pass throughthe less light can pass through

• Translucent and OpaqueTranslucent and Opaque• High melting pointsHigh melting points

What are the characteristics What are the characteristics of polymers?of polymers?

Characteristics of PolymersCharacteristics of Polymers Most polymers have the following general attributes. Most polymers have the following general attributes.

• 1. Polymers can be very resistant to chemicals. 1. Polymers can be very resistant to chemicals. Consider warning labels on cleaning fluids (ex. when chemical comes in contact Consider warning labels on cleaning fluids (ex. when chemical comes in contact

with skin or eyes)with skin or eyes)• 2. Polymers can be both thermal and electrical insulators.2. Polymers can be both thermal and electrical insulators.

Consider wiring in your house or handles of pots and pansConsider wiring in your house or handles of pots and pans• 3. Generally, polymers are very light in mass with varying degrees of 3. Generally, polymers are very light in mass with varying degrees of

strength.strength. Ex. Toy or structure of Space Station. Nylon Pantyhose or Kevlar Bulletproof Ex. Toy or structure of Space Station. Nylon Pantyhose or Kevlar Bulletproof

VestsVests• 4. Polymers can be processed in various ways to produce thin fibers or 4. Polymers can be processed in various ways to produce thin fibers or

very intricate parts.very intricate parts. Ex. Bottles or body of a car. Styrofoam and urethaneEx. Bottles or body of a car. Styrofoam and urethane

Identification TestsIdentification Tests• Melting point, burning properties, solubility, relative density, etc.Melting point, burning properties, solubility, relative density, etc.• Elasticity and flexibility Elasticity and flexibility 

Forms of PlasticsForms of Plastics Extrusion Extrusion

• Customarily designed to make a variety of objects (ex. Customarily designed to make a variety of objects (ex. straws, molding, hose and tubing, vinyl siding)straws, molding, hose and tubing, vinyl siding)

Sheeting Sheeting • Rollers produce sheets to a desired thickness (ex. food Rollers produce sheets to a desired thickness (ex. food

packaging)packaging) Fibers and Filaments Fibers and Filaments

• Create synthetic fibers that resemble natural fibersCreate synthetic fibers that resemble natural fibers Molded Molded

• Forced under pressured into a closed moldForced under pressured into a closed mold Blow molding Blow molding

• Air forces material against walls of a mold (ex. two-liter Air forces material against walls of a mold (ex. two-liter soft drink bottles)soft drink bottles)

Rotational molding Rotational molding • Powered plastic is placed into a mold and is heated and Powered plastic is placed into a mold and is heated and

rotatedrotated Adhesives Adhesives

• Bond materials togetherBond materials together

Did You Know?Did You Know?

It would take seven truckloads of It would take seven truckloads of paper bags to deliver the paper bags to deliver the equivalent of one truckload of equivalent of one truckload of plastic bags -- the fact that plastic bags -- the fact that plastic is lightweight helps lower plastic is lightweight helps lower transportation costs and transportation costs and conserve natural resources.conserve natural resources.

Common Plastic Resins Used in Common Plastic Resins Used in PackagingPackaging

Polyethylene Terephthalate (PET or Polyethylene Terephthalate (PET or PETE):PETE):

• Qualities:Qualities: Clarity, strength/toughness, barrier to gas, resistance to Clarity, strength/toughness, barrier to gas, resistance to grease/oil, stiffness, resistance to heat.grease/oil, stiffness, resistance to heat.

• Uses: Uses: Plastic soft drink bottles, mouthwash bottles, peanut butter and Plastic soft drink bottles, mouthwash bottles, peanut butter and salad dressing containers.salad dressing containers.

• Recycled Products: Recycled Products: Tote bags, dishwashing liquid containers, Tote bags, dishwashing liquid containers, clamshells, laser toner cartridges, picnic tables, hiking boots, lumber, clamshells, laser toner cartridges, picnic tables, hiking boots, lumber, mailbox posts, fencing, furniture, sweatshirts. mailbox posts, fencing, furniture, sweatshirts. 

Common Plastic Resins Used in Common Plastic Resins Used in PackagingPackaging

High Density Polyethylene (HDPE): High Density Polyethylene (HDPE):

• Qualities: Qualities: Stiffness, strength/toughness, low cost, ease of forming, Stiffness, strength/toughness, low cost, ease of forming, resistance to chemicals, permeability to gas, ease of processing.resistance to chemicals, permeability to gas, ease of processing.

• Uses:Uses: Milk, water and juice containers, grocery bags, toys, liquid Milk, water and juice containers, grocery bags, toys, liquid detergent bottles.detergent bottles.

• Recycled Products: Recycled Products: Recycling bins, benches, bird feeders, retractable Recycling bins, benches, bird feeders, retractable pens, clipboards, fly swatters, dog houses, vitamin bottles, floor tile, pens, clipboards, fly swatters, dog houses, vitamin bottles, floor tile, liquid laundry detergent containers.liquid laundry detergent containers.

Common Plastic Resins Used in Common Plastic Resins Used in PackagingPackaging

Vinyl (Polyvinyl Chloride or PVC):Vinyl (Polyvinyl Chloride or PVC):

• Qualities: Qualities: Versatility, ease of blending, strength/toughness, resistance Versatility, ease of blending, strength/toughness, resistance to grease/oil, resistance to chemicals, clarity, low cost.to grease/oil, resistance to chemicals, clarity, low cost.

• Uses: Uses: Clear food packaging, shampoo bottles.Clear food packaging, shampoo bottles.• Recycled Products: Recycled Products: Air bubble cushioning, flying discs, decking, film, Air bubble cushioning, flying discs, decking, film,

paneling, recycling containers, roadway gutters, snowplow deflectors, paneling, recycling containers, roadway gutters, snowplow deflectors, playground equipment.playground equipment.

Common Plastic Resins Used in Common Plastic Resins Used in PackagingPackaging

Low Density Polyethylene (LDPE): Low Density Polyethylene (LDPE):

• Qualities: Qualities: Ease of processing, barrier to moisture, strength/toughness, Ease of processing, barrier to moisture, strength/toughness, flexibility, ease of sealing, low cost.flexibility, ease of sealing, low cost.

• Uses: Uses: Bread bags, frozen food bags, grocery bags.Bread bags, frozen food bags, grocery bags.• Recycled Products: Recycled Products: Shipping envelopes, garbage can liners, floor tile, Shipping envelopes, garbage can liners, floor tile,

furniture, film, compost bins, paneling, trash cans, landscape timber, furniture, film, compost bins, paneling, trash cans, landscape timber, mud flaps.mud flaps.

Common Plastic Resins Used in Common Plastic Resins Used in PackagingPackaging

Polypropylene (PP): Polypropylene (PP):

• Qualities: Qualities: Strength/toughness, resistance to chemicals, resistance to Strength/toughness, resistance to chemicals, resistance to heat, barrier to moisture, low cost, versatility, ease of processing, heat, barrier to moisture, low cost, versatility, ease of processing, resistance to grease/oil.resistance to grease/oil.

• Uses: Uses: Ketchup bottles, yogurt containers and margarine tubs, medicine Ketchup bottles, yogurt containers and margarine tubs, medicine bottles.bottles.

• Recycled Products:Recycled Products: Signal lights, battery cables, brooms and brushes, Signal lights, battery cables, brooms and brushes, ice scrapers, oil funnels, landscape borders, bicycle racks.ice scrapers, oil funnels, landscape borders, bicycle racks.

Common Plastic Resins Used in Common Plastic Resins Used in PackagingPackaging

Polystyrene (PS):Polystyrene (PS):

• Qualities: Qualities: Versatility, insulation, ease of processing, low cost, clarity.Versatility, insulation, ease of processing, low cost, clarity.• Uses: Uses: Videocassette cases, compact disc jackets, coffee cups, knives, Videocassette cases, compact disc jackets, coffee cups, knives,

spoons and forks, cafeteria trays, grocery store meat trays and fast-spoons and forks, cafeteria trays, grocery store meat trays and fast-food sandwich containers.food sandwich containers.

• Recycled Products: Recycled Products: Thermometers, light switch plates, insulation, egg Thermometers, light switch plates, insulation, egg cartons, vents, desk trays, rulers, license plate frames, concrete.cartons, vents, desk trays, rulers, license plate frames, concrete.

ResourceResource

http://www.americanchemistry.com/shttp://www.americanchemistry.com/s_plastics/hands_on_plastics/intro_to__plastics/hands_on_plastics/intro_to_plastics/teachers.htmlplastics/teachers.html

Review Key QuestionsReview Key Questions

What is a Polymer?What is a Polymer? What does a polymer look like on the What does a polymer look like on the

molecular level? molecular level? What are the characteristics of What are the characteristics of

polymers?polymers?

LabLab

Complete the Polymer Lab.Complete the Polymer Lab.

Mini-ProjectMini-Project

Complete the “Are Plastics Complete the “Are Plastics Dangerous” project?Dangerous” project?