spot the plastic orcan you think of the names of any polymers (except rubber)? polythene...
TRANSCRIPT
...RESISTANT MATERIALS
Spot the plastic or....
A LEVELTheory
AS
DT
Expanded Polystyrene Epoxy resin Polypropylene
Polythene PVC
...RESISTANT MATERIALS
Today
A LEVELTheory
AS
DT
Produce a 2-3 minute PowerPoint presentation about the following plastics:
•A B S •Acrylic •HDPE •LDPE •PET •PVC•PP •PS
It must include: Properties (advantages)Disadvantages Applications
Printed factsheets for your colleagues (8)Try to include an activity
Deadline – Tuesday
...RESISTANT MATERIALS
Thermosetting plastics
A LEVELTheory
AS
DT
What are they?
Plastics that cannot be reheated and reformed.
Epoxy Resin Polyester Resin Urea Formaldehyde
...RESISTANT MATERIALS
Plastics Quiz
A LEVELTheory
AS
DT
1. Name the type of plastic used for this product (1)
2. State three reasons why this material is used (3)
3. Name a disadvantage of this material (1)
4. Name another product made using this material (1)
a.
b.
c.d.
...RESISTANT MATERIALS
Polymers (plastics)
Describe the process of addition polymerisation (2)
Decribe the process of condensation polymerisation (2)
Sketch and label the microstructure of the following
-Thermoplastic (2)-Thermosetting plastic (2)
Name a polymer that is a modified natural material (1)
A LEVELTheory
AS
DT
...RESISTANT MATERIALS
Polymers (plastics)
A LEVELTheory
AS
DT
So what are polymers....Organic materials based on the carbon element
Are they natural, modified natural materials or synthetic?
Natural polymers include amber or shellac
Modified natural materials include cellulose or casein
Synthetic polymers include crude oil products
...RESISTANT MATERIALS
Polymers (plastics)
A LEVELTheory
AS
DT
There are three main groups of polymers, what are they?
Thermoplastics Thermosetting plastics
Elastomers
These are plastics that can be formed and then reheated and reshaped.
These plastics are mainly recyclable.
Once these plastics have been formed (more difficult than thermoplastics) they cannot be reshaped.
These plastics remain hard at high temperatures.
These are polymers with the property of elastic.
Think rubber and rubber mixed with other materials (adding sulphur to rubber – more rigid)
...RESISTANT MATERIALS
Polymers (plastics)
A LEVELTheory
AS
DT
Can you think of the names of any polymers (except rubber)?
Polythene (polyethylene)
Polyvinyl chloride (PVC)
Polystyrene
Polypropylene
Polymethyl methacrylate (acrylic...)
Polyester resin
Polyurethane
Epoxy resin
Plastic bottles
Records, guttering
Flower pots, packaging
Plastic chairs, DVD cases
Signs
Furniture, boats (w GRP)
Paint
Glue
...RESISTANT MATERIALS
Polymers (plastics)
A LEVELTheory
AS
DT
The basic building block of polymer is a monomer.
The process of polymerisation connects many of these monomers together to form a polymer chain.
These polymer chains entangle themselves to become a polymer structure.
...RESISTANT MATERIALS
Polymers (plastics)
There are two main types of polymerisation:
Addition polymerisation
-The chemical linking of thousands of small identical monomers to form a polymer
Condensation polymerisation – Two different monomers, which react to each other, are linked together
A LEVELTheory
AS
DT
...RESISTANT MATERIALS
Polymers (plastics)
A LEVELTheory
AS
DT
Addition polymerisation – the chemical linking of thousands of identical monomers to form a polymer
C = C
H H
HH
The Ethylene or Ethene Monomer
This may be ‘added’ to other ethylene monomers to form polyethylene or polythene
H – C – C – C – C – C – C – H
H H H HH H
H H H H H H
...RESISTANT MATERIALS
Polymers (plastics)
A LEVELTheory
AS
DT
Addition polymerisation – the chemical linking of thousands of identical monomers to form a polymer
Ethane CH3‐CH3 2 C atoms gas
Butane CH3‐CH2‐CH2‐CH3 4 C atoms liquid
Paraffin CH3(CH2CH2)10CH3 22 C atoms wax
Polyethylene CH3(CH2CH2)2000CH3 4002 C atoms solid
...RESISTANT MATERIALS
Polymers (plastics)
Condensation polymerisation – two different monomers (a catalyst + resin), which react to each other, link together
A LEVELTheory
AS
DT
C – C – C – C – C – C
HO H H HH O
O H H H H HO
N – C – C – C – C – N
H H H HH H
H H H H H H
+
The two monomers (adipic acid and hexamethylene) link together
With a by-product of water which is not present in the resulting polymer (not shown)....Nylon (polyamide)
Do you know how they came up with the name Nylon?
...RESISTANT MATERIALS
Polymers (plastics)
A LEVELTheory
AS
DT
The microstructure of thermoplastics
Thermoplastics are made up of long chains of strong covalent bonds along the carbon – carbon backbone.
The chains become entangled.
Where the chains are close, weaker Van der Waals forces hold the structure together. (held together by mutual attraction)
Van der Waals forces & water molecules
...RESISTANT MATERIALS
Polymers (plastics)
A LEVELTheory
AS
DT
The microstructure of thermosetting plastics
Adjacent polymer chains are held together after the chemical reaction by strong cross-linking covalent bonds
Giving the polymer a more rigid 3D structure in which the atoms cannot move easily (linked side to side and end to end)
Note: A covalent bond is a chemical bond formed by the sharing of one or more electrons, especially pairs of electrons, between atoms.
...RESISTANT MATERIALS
Epoxy Resin (polyepoxide)
A LEVELTheory
AS
DT
Thermosetting polymerResin (epoxide) and a hardnener (polyanime) – a copolymer
Needs time to cure (dependent on ratio of above) Cured by UV light Heating can speed up the process
Applications
•Adhesives •High performance flooring •Finishes•Moulded Objects – can be used in carbon fibre
Adv Disadv
Corrosion resistant Electrical resistant Good bond qualities Good heat resistance
Can cause allergic reactionsSuspected of health problems
Used on a surfboard
...RESISTANT MATERIALS
Urea formaldehyde
A LEVELTheory
AS
DT
A non transparent thermosetting resin or plasticUrea and formaldehyde heated with ammonia as a base
Applications Electrical fittings /casing Domestic appliance componentsLargely used in timber industry – MDF/laminatingButtons
Adv Disadv
High tensile strength High surface hardness Heat resistant Relatively low price Scratch/stain resistant
Can emit toxic vapours during manufacturing Brittle
...RESISTANT MATERIALS
Polyester resin
A LEVELTheory
AS
DT
Used in sheet moulding compound and bulk moulding compound
Cures with a catalyst – cures exothermically (generates heat as it cures)
Adv Disadv
Good electrical insulator Heat resistant Good resistance to water
Brittle Can crack Contracts on curing
ApplicationsGlass reinforced plastic – boats + carsGarden furniture Casting
...RESISTANT MATERIALS
Acrylic
A LEVELTheory
AS
DT
Used in
Adv Disadv
Good Impact strength Lightweight Good electrical insulator Durable StiffHard
Poor chemical resistance Scratches easilyBrittle – can break
ApplicationsOrnamental Fish tanksBaths/Bathroom furnitureCar indicator covers Lighting
...RESISTANT MATERIALS
HDPE
A LEVELTheory
AS
DT
Used in
Adv Disadv
Good electrical insulatorExcellent Chemical resistant Impact resistant Flexible Soft Tough
Colour fades over time Can break under stress
ApplicationsToysWashing up bowls Buckets Shampoo bottle s
...RESISTANT MATERIALS
LDPE (low density polyethylene)
A LEVELTheory
AS
DT
Used in
Adv Disadv
Good B
ApplicationsCarrier bagsPackaging film
Adv Disadv
Good electrical insulatorChemical resistant Flexible Soft Tough
Colour fades over time Can break under stress
...RESISTANT MATERIALS
PET (polyethylene terephthalate)
A LEVELTheory
AS
DT
Used in
Adv Disadv
Good alcohol and oil barrierChemical resistant High impact resistance High impact strength
Can discolour When used with foodstuffs needs to be treated to prevent taste problems
ApplicationsDrinks bottles
...RESISTANT MATERIALS
PVC (Poly vinyl chloride)
A LEVELTheory
AS
DT
Used in
Adv Disadv
Good chemical resistanceWeather resistant LightweightGood electrical insulatorHardTough Waterproof Durable
Can be recycled Relatively cheap to manufacture Becomes brittle over time UV light causes degradation
ApplicationsElectrical wiring insulation Pipes Guttering Floor covering
...RESISTANT MATERIALS
PP (polypropylene)
A LEVELTheory
AS
DT
Used in
Adv Disadv
Impact resistantFlexible – resistant to fatigue LightHardChemical resistant
UV light causes degradationOxidation can be a problem during manufacture
ApplicationsChairs Rope Carpets Kitchenware
...RESISTANT MATERIALS
PS (polystyrene)
A LEVELTheory
AS
DT
Expanded
Adv Disadv
BuoyantLightweight Good insulator
Crumbles and breaks Easily ignites
ApplicationsPackaging Buoys
Compressed/Rigid or HIPS
Adv Disadv
LightHardStiff Brittle Low impact strength
WeakIgnites easily
ApplicationsWater tanks CD cases Disposable cups
...RESISTANT MATERIALS
ABS (Acrylonitrile butadiene styrene)
A LEVELTheory
AS
DT
Used in
Adv Disadv
Chemical resistant Hard Tough Scratch resistant LightweightGood resistance to chemicals
Relatively expensive compared with polystyrene UV light causes degradation
ApplicationsKitchenware Camera cases Toys Car components Phone cases
...RESISTANT MATERIALS
Quiz
A LEVELTheory
AS
DT
Bath, shampoo bottles, bath board