Polymers Flashcards
Name some polymer characteristics
Toughness
Elasticity
Insulation (thermal and elasticity)
UV resistance
Ability to be moulded
Resistance to chemicals and liquids
Melting points
Suitability for food packaging applications
Biodegradability
Recyclability
Self finishing
Ability to be combined with other polymers and/or additives
Name some bio degradable plastics (bio plastics)
- corn starch polymer
- Potatopak
- Biopol
- PLA
- PHA
- Lactide
- Eco film
Degradation occurs in the presence of ….
Light - photodegradable
Oxygen - (oxy-degradable)
Water - degradable
What are the 2 bio plastics ?
Natural bio polymer , synthetic bio polymer
Whats another word for thermoplastics ?
Thermoforming plastics
What are the 3 types of plastics ?
Thermoplastics and thermosetting plastics and elastomers
What are thermoplastics ?
Thermoplastics are plastics that will return to their original shape when heated till soft. They have a thing called “plastic memory”.
At what temp do thermoplastics usually soften at ?
Thermoplastics generally soften at low temps ( as low as 100 degrees C ). This makes them inappropriate for products that involve relatively high temperatures. However thermoplastics are the most common type of plastic and are widely used for everyday products
What are thermosetting plastic ?
They are very different from thermoplastics. When they are being formed a chemical reaction occurs causing them to create strong in their structure which means that they are permanently formed and cannot be softened by reheating. Because they do not soften, they can take very high temps often in excess of 400 degrees C. This makes thermosetting plastics very good for kitchen tools as they wont melt. Also they usually just start burning if you heat them enough
What are elastomers ?
Elastomers have very good elasticity for e.g. they can be distorted under pressure but will return to their original shape when the pressure is removed. Elastomers have long chain molecules that can be considered to be coils - this is what causes them to be elastic. When the material is being distorted, the molecules distort, and then when the materials stop being distorted then they return to their original shape.
What are the 2 types of elastomers ?
Thermosetting - natural or synthetic rubbers, cannot be recycled or reshaped, e.g, liquid silicon rubber
Thermoplastic - can be reheated and reshaped therefore recycled, can be manufactured using conventional equipment such as injection moulding or blow moulding
Name some thermoplastics
- HDPE - high density polyethylene
- PMMA - Poly ( methyl methacrylate ) - acrylic
- HIPS - High impact polystyrene
- Nylon
- ABS - Acrylonitrile butadiene styrene
- LDPE - Low density polyethylene
- PVC - Polyvinyl Chloride
Name some thermosetting plastics
- Urea Formaldehyde
- Epoxy resin
- Melamine formaldehyde
- Resin
Name some elastomers
- Silicone
- Neoprene
- Buradiene Rubber
- Natural rubber - Polyisoprene
What plastic are kids blow up swimming pools made out of ?
PVC - flexible polyvinyl chloride
What are the car headlights made of ?
PMMA - acrylic
What plastic are sockets made of ?
Urea Formaldehyde - UF
What are gas canisters made out of ?
HDPE - High density polyethylene
What type of plastic would a folder be made out of ? ( something like an art folder )
Polypropylene - PP
Or
PVC - Poly-vinyl Chloride
What are polymer enhancements ?
Enhancing a polymers properties by using additives ( adder to a polymers stock form for a variety of reasons )
It is a way of improving a materials properties to better suit the requirements of the final product
What do fillers do to a polymer ?
Fillers improve performance and / or reduce production costs and fillers can also improve the plastics impact resistance
What are pigments ?
They are tiny particles that are mixed into the polymer in its molten state to give colour to the processed product
What does the biodegradable plasticiser do ?
These make the polymer more flexible, softer and easier to break down, which means faster degradation time
What are lubricants ( polymer enhancements ) ?
Lubricants as additives for polymers assist the movement of one object passing another object. Their primary role is to reduce friction, minimize wear and prevent overheating of parts.
What are thermal antioxidants ?
Antioxidants protect plastics and other materials against thermally induced oxidation. This process can lead to a number of undesirable effects, including discoloration, changes in melt viscosity, and deterioration of mechanical properties. As a result, the useful life of the polymer or final article is limited.
In short it gives thermal protection to plastics
