M4 - Non-metals, Plastics Flashcards
plastic
synthetic or semi-synthetic organic solids that are moldable
two classes of plastics
thermoplastics
thermosetting plastics
thermoplastics
can be softened by heating and hardened by cooling without changing the properties; reusable
thermosetting plastic
can be softened by heating then hardens permanently
properties of plastics
light good chemical resistance insulators resists corrosion moldable can be transparent or colored
types of plastics
PET HDPE PVC LDPE PP PS Miscellaneous
polyethylene terephthalate (PET)
absorbs odor and flavors from foods and drinks that are stored in them;
commonly recycled
high-density polyethylene (HDPE)
- It is very safe and not known to transmit any chemicals into foods and drinks.
- NEVER safe to reuse HDPE for things they weren’t originally used for.
- commonly recycled
polyvinyl chloride (PVC)
- commonly used for tiles and pipes
- should not come into contact with food
- sometimes recycled
low-density polyethylene (LDPE)
- very healthy plastic that tends to be both durable and flexible
- used as plastic bags, cling film
- sometimes recycled
polypropylene (PP)
- strong and can withstand higher temperature
- occasionally recycled
polystyrene (PS)
- used for packing items/food, disposable cups
- commonly recycled, but hard to do
Miscellaneous types of plastics (Code 7)
- plastics that did not fall under the other categories
- plastics that are difficult to recycle
- Ex. polycarbonate (PC) and polylactide (PLA)
production processes of plastics (9)
compression molding transfer molding injection molding extrusion molding blow molding calendering thermoforming rotational forming laminating
compression molding
pressure is applied so the compound flows and hardens into the shape of the mold
