Polymers - Thermosetting Plastics Flashcards
What are the two groups?
Ivan K
Thermoplastics and Thermosetting plastics
Examples of Thermoplastics
Ivan K
Acrylic Polythene Polypropylene PET ABS PVC
Properties of ThermoPlastics
Ivan K
Will soften when heated
Tend to be flexible
Impact resistant
can be coloured
Examples of Thermosetting plastics
-Ivan k
GRP- Glass Reinforced polyester
Bakelite
Phenol
Epoxy Resin(e.g Araldite)
What is an efficient way of producing large quantities of identical plastic items?
Ivan K
Injection Moulding
Where are thermoplastics used?
Mechanical parts or even plastic bags
Are thermoplastics expensive to process?
No
Are thermoplastics recyclable?
Yes
Is Teflon a thermoplastic?
Yes
Is PVC a thermoplastic?
Yes
What is needed to start Injection Moulding?
-Oscar Lawson
Thermoplastics in granulated or powdered for which are fed into the hopper.
What is the rotating screw in the steel barrel of an injection moulder called?
-Oscar Lawson
Archimedes screw. It carries plastic from barrel to mould whilst the material is heated.
What happens once the thermoplastics have heated up (in injection moulding)
-Oscar Lawson
The hot material builds up at the ends before being injected into the mould.
What is the entrance into the cavity of the mould called?
-Oscar Lawson
A spruce
What steps are taken to ensure successful injection moulding?
-Oscar Lawson
The mould is heated beforehand to avoid setting the plastic too rapidly
Pressure is kept to prevent shrinkage. This returns a better product quality.
What are the properties of thermoplastics?
- Krystian Shanahan
Will soften when heated
Flexible
Impact resistant
Can be coloured
What is a CIM?
-Krystian Shanahan
Computer integrated manufacture
How is plastic fed into the injection moulding machine ?
-Krystian Shanahan
Through a hopper
Through what device is plastic injected into the mould?
-Krystian Shanahan
A sprue
Why is pressure maintained during dwell time?
-Krystian Shanahan
To prevent the material creeping back during setting
What is another name for Plastics?
- Humphrey Marsh
Polymers
A plastic is made up of what?
- Humphrey Marsh
A long chain of molecules
What defines the properties of a material?
- Humphrey Marsh
How long chained molecules are linked together
The long chain molecules in thermosetting plastics are chemically tied by what and what links them?
- Humphrey Marsh
Covalent bonds and they are cross-linked
Thermosets have little plasticity and are what?
- Humphrey Marsh
Rigid
What is a downside of thermosetting plastics?
Yan K
They can only be formed once
What do thermoplastics have?
Yan K
Good heat resistance
What is UF used for?
Yan K
Electrical fittings, domestic appliance part, adhesives, coating paper, textile
What is MF used for?
Yan K
Tableware, decorative laminates for work surfaces, electrical insulation, buttons
What is PR used for?
Yan K
Casting, encapsulation, embedding, panels, boats, car bodies, chair shells, containers
In thermoplastics, what force holds the long chain molecules together?
-Oscar Mabon
Van der waals forces of attraction.
Is Acrylic a thermoplastic?
-Oscar Mabon
Yes
Is PVC a thermoplastic?
-Oscar Mabon
Yes
Is Polythene a thermoplastic?
-Oscar Mabon
Yes
Is Polypropylene a thermoplastic?
-Oscar Mabon
Yes
Can Melamine Formaldehyde sheets be printed and laminated onto Particle Boards?
Caspar Tyser
Yes
Compression Moulding requires………?
Caspar Tyser
Heat and Pressure
Can Thermosetting Plastics be re-heated and moulded after they have already been heated and moulded?
Caspar Tyser
No
Can Thermoplastics be re- heated and moulded once this cycle has already occurred?
Caspar Tyser
Yes
Thermosetting plastics are tied by covalent bonds and are…?
Caspar Tyser
Cross-linked
What is GRP short for?
-Oscar Lawson
Glass reinforced paper
What does a hardener do to epoxy resin?
-Oscar Lawson
Causes a reaction forming crosslinking between the long chain molecules
What is urea formaldehyde used for?
-Oscar Lawson
Electrical fittings like plug sockets, wood adhesives and laminating particle boards such as MDF
What would you use melamine for?
-Oscar Lawson
Plastic plates and cups as it is very heat resistant and can be printed and coloured
How does compression moulding work?
-Oscar Lawson
Powder is measured out and placed into a mould. The mould is closed under pressure and heat, curing the plastic.
What are long chain molecules held together by?
Nathan P
Forces of attraction called van der waals
What allows thermoplastics to be reformed and moulded?
Nathan P
The fact that they soften when heated
Properties of thermoplastics:
Nathan P
Soften when heated
Tend to be flexible
Impact resistant
Can be coloured
How many times can thermosetting plastics be moulded?
Nathan P
Only once, then they are permanently rigid.
Injection moulding uses what kind of plastics?
Nathan P
Thermoplastics
What are the two groups of plastics?
Torsai K
Thermoplastic and Thermosetting plastics
What is injection moulding?
Torsai K
The process is used to produce large quantities of identical plastic items
What are examples of thermoplastics?
Torsai K
Acrylic, Polythene, Polypropelene, PET, ABS, PVC
What are the characteristics of thermoplastics?
Torsai K
Thermoplastics soften when heated, tend to be flexible, are impact resistant, and can be coloured.
Why is injection moulding only reserved for volume production?
Torsai K
Moulds can be quite expensive. Due to the high cost, moulding should be reserved for volume production
What is epoxy resin used for?
-Ssnehnil G
It acts like a glue
Use of Urea Formaldehyde?
-Ssnehnil G
Electrical fittings, plugs and sockets
What does GRP stand for?
-Ssnehnil G
Glass Reinforced Polyester
What is Phenol Formaldehyde also known as?
- Ssnehnil G
Bakelite
Are thermosetting plastics rigid?
-Ssnehnil G
Yes
What is plastic?
Torsai K
Plastics are a group of materials which are ‘plastic’ at some point in the manufacturing process
What are examples of thermosetting plastics?
Torsai K
GRP, Melamine, Bakelite, Urea Formaldehyde, and Epoxy resin (Araldite).
How are thermoplastics different from thermosetting plastics?
Torsai K
A thermoplastic will soften when heated; a thermosetting plastic will not.
Characteristics of thermosetting plastics.
Torsai K
Thermosetting plastics withstand higher temperatures without losing rigidity and are good insulators.
How do thermosetting plastics form?
Torsai K
Thermosetting plastics begin as long-chain molecules but become chemically tied and are cross-linked when polymer cures.
What is compression moulding?
Torsai K
A precise amount of powder is placed in a mould, closed under pressure with heat applied, and plastic cures.
Are thermosetting plastics recyclable?
No
What type of molecular structure do thermosetting plastics have?
Rigid
How are the What type in thermosetting plastics linked?
Cross-linked
What process are thermoplastics made through?
Cross-linked
Do thermosetting plastics soften under heating?
No
What is a plastic?
-Lucas M
A material that is ‘plastic’ at some point in the manufacturing process.
What force of attraction holds thermoplastics together?
-Lucas M
Van Der Waals forces of attraction.
Why can thermoplastics be reformed multiple times?
-Lucas M
It softens when heated.
Which thermosetting plastic resists heat to 250 degrees Celsius?
-Lucas M
Epoxy resin
Which thermosetting plastic is scratch resistant and comes in a wide range of colours?
-Lucas M
Melamine-formaldehyde
What are plastics also known as?
Nathan P
Polymers
Melamine can be…
Nathan P
Printed, coloured and is resistant to heat
Laminating can make a particle board…
Nathan P
Hard, coloured and heat resistant
GRP stands for…
Nathan P
Glass reinforced polyester
What is required for epoxy resin to set?
Nathan P
Resin and hardener
How many times can thermosetting plastics be formed?
-Alfie Turner
once
Do thermosetting plastics have good resistance to heat?
-Alfie Turner
YES
Thermoplastics have little plasticity and are …?
-Alfie Turner
rigid
What does epoxy resin require to set?
-Alfie Turner
A hardener
How can melanin be used?
-Alfie Turner
Printing, colouring and its resistant to heat