Ch. 13: Sustainability & Recycling

Biodegradable

Ability to break down into smaller and smaller pieces

Sustainability

Capacity to endure

Life-cycle assessment

• Also called cradle to grave analysis

• Tracks a product from raw material to its disposal

• Accounts for all energy and materials that go into making a product + disposing it

• Determines cost + environmental impact of a process

Steps in making plastic cups:

1. Crude oil obtained

2. Refine crude oil

3. Oil drilling + refining process requires energy

4. Petroleum byproducts used to make plastic transported to factory

5. Energy usage counted

6. Item made → packaging + raw materials to make + obtain

7. Transported to distribute

Cradle-to-grave design steps:

1. Raw materials harvested

2. Product made in a factor

3. Product sold

4. Take home for use

5. Discard

Cradle-to-cradle design

Plan for product reuse

Plastic

• Material capable of being shaped into any form

• Makes up 1/5 of average landfill

Lightweighting

Process of reducing mass of plastic used to make container to hold given volume of something

Polymer

• A molecule of high molecular weight formed by repeated chemical linking smaller organic molecules (monomers)

• Connected to form long chains

• Short or long, branched or straight structures

• Stretchy

• Extremely large / macromolecules

• Biodegradable

• Have various physical properties

Monomers

Individual structures linked to form a polymer

Polyisoprene

• Nonpolar carbon-carbon and carbon-hydrogen bonds

• Hydrophobic / water-proof substance

Polar polymers are…

Hydrophilic / water loving

Carbon-nitrogen bonds are….

Inflexible

Kevlar

Made from a rigid inflexible polymer

Benzene ring

Adds rigidity to a polymer

What makes a polymer stronger?

Closely packed strands that form cross-lining between strands

Crystallite

Highly ordered, crystalline region in a polymer

Thermoplastic polymers

• Melts upon heating, becoming moldable

• Stiffens to a solid upon cooling

  • ex. plastic forks, cell phones, pens

Thermosetting polymers

• Hardens permanently / does not melt

• May discolor

• Extremely tough

• Not moldable when heated

  • ex. jet engines

Resin ID code of 1

Polymer is easily recycled

• ex. polyethylene terephthalate (PET)

Resin ID code of 6

Polymer harder to recycle

• ex. Polystyrene

Resin ID code of 7

Plastic is a mixture of different polymers