question
What is a monomer
small atoms or molecules that bond together to form polymers
what is polymerization
process of forming polymers from monomers
What are the 2 types polymerization?
Addition and condensation polymerization.
What are the examples?
polyethene, polypropene, nylon and cellulose
what are plastics
synthetic polymers
What are the 5 desirable properties of plastics?
Strength and durability, flexibility, lack of reactivity, thermal and electrical insulation.
who produces plastics and how
they are produced in vast quantities by the petrochemicals industry, and come from organic chemicals derived from crude oil
where are plastics used(in everyday items), and name the plastic (there are 3 different plastics mentioned)
polyethene is used in plastic bags, plastic bowls, and plastic bottles
polychloroethene is used in insulation for electrical cables or in window frames
polypropene is used in car bumpers and carpet fibres
what are the two types of structures of plastics
amorphous and semi crystalline
why can't thermosets be remoulded
What is thermoplastic and example?
When there is only intermolecular forces between the plastics, called thermoplastic. PVC and polyethene.
Which plastic has good strength and durability and flexbility?
HDPE, PVC, Polychloroethene, nylon and perpex.
LDPE
explain the amorphous structure of plastics
amorphous means it's a random structure with chains arranged like in a plate of spaghetti
explain the semi-crystalline structure of plastics
semi crystalline means they're amorphous, but have some regions that are more ordered and packed more closely together
what are thermosets
polymers with extensive cross linking that cannot be remoulded
what are cross-links
covalent bonds
explain an example of synthetic thermosets
what is vulcanization
process of treating crude or synthetic rubber or similar plastic material chemically to give it useful properties
examples of thermosets
bakelite and polyurethanes
do cross-links occur naturally or synthetically
Both. Cross links can form synthetically (like natural rubber turning stronger and more rigid) or naturally (like collagen)