New materials

Question 1

Kevlar definition

Answer 1

artificial fibre which is very tough and high tensile strength due to its density. Strong and very light - can be used as bulletproof vests, planes

Question 2

Smart materials definition

Answer 2

responsive materials that are designed to react to external stimuli, the can alter the function or aesthetic properties in response to changing environment

Question 3

Smart materials examples

Answer 3

polymorph, shape memory alloy, thermochromic materials, photochromic materials, quantum tunnelling composite, kevlar

Question 4

Polymorph definition

Answer 4

can be shaped and reshaped many times, when warmed it becomes flexible and easy to mould, sets hard

Question 5

Shape memory alloy definition, pros, cons and uses

Answer 5

revert back to its original shape after being deformed.
Pros - super elasticity - can be bent without permanently deforming, immediately recovers original shape, lightweight and durable
Cons - not unbreakable, more expensive
Uses - braces, treating blocked arteries

Question 6

Quantum tunnelling composite definition and uses

Answer 6

flexible polymer with tiny metal particles embedded into it, when the material is squeezed the pressure forces the particles together and a current of electrons flows between the neighbouring particles, uses - microswitches, outdoor items that may be affected by water, touch sensitive pads, tools, medicine

Question 7

Thermochromic material definition, pros, cons and uses

Answer 7

temperature sensitive, change colour when exposed to different temperatures
Pros - immediate visual indication, safety feature, aesthetic appeal
Cons - limited colour range, could possibly indicate wrong temperature
Uses - inks, plastics to indicate temperature, baby stuff

Question 8

Photochromic materials definition and uses

Answer 8

change colours when exposed to different UV levels, over time will degrade from overexposure, uses - glasses lenses, inks, toys

Question 9

Smart glass definition, pros, cons and uses

Answer 9

it becomes clear when a current is flowing through it and opaque when no electricity.
Pros - controls the amount of heat passing through - saving energy costs, provides shade, privacy
Cons - expensive, requires constant electricity, speed of control
Uses: windows, welding shields

Question 10

Kevlar definion and uses

Answer 10

very impact resistant, tough with high tensile strenth. Uses: bulletproof vests

Question 11

Precious metal clay definition and uses

Answer 11

contains microscopic oarticles of metal so is pliable but when heated the particles fuse and leaves behind just the metal. Uses: jewellery, intricate parts

Question 12

Nanomaterials definition and uses

Answer 12

use of nanoparticles. Uses: medical and cosmtics, energy applications -> graphene

Question 13

Smart fluid definition, pros, cons and uses

Answer 13

contains metallic elements altering viscosity when a magnetic field is applied
Pros - improves handling as it adapts to road, better and faster control
Cons - more expensive
Uses: suspension

Question 14

Thermo ceramics definition, pros, cons and uses

Answer 14

made by combing ceramic and metallic powerders and then heated and put in a die under high pressue so the particles bond with each other.
Pros - very hard. very stable at high temperatures.
Cons - brittle, cracks in cermaics, more expensive
Uses - turbine blades, racing car parts

Question 15

Glass reinforced plastic definition, pros, cons and uses

Answer 15

made of epoxy resin reinforced by woven fibres of glass
Pros - good strength to weight ratio, resistant to corrosion and water, wide range of colours, can be repaired easily
Cons - expensive, specialised manufacturing process, mould needed
Uses - boats, canoes, vehicle bodies

Question 16

Process of making GRP

Answer 16

1. mould is made and checked
2. releasing agent is added
3. first layer of resin is applied to the mould and is left to set
4. layer of fibre glass is added and the resin in added and rolled into the fibres
5. this layer is then cured and the next layer is added and resin in rolled and this repeats
6. left to cure then removed from mould and finished to leave highly polished look

Question 17

Carbon fibre definition, pros, cons and uses

Answer 17

carbon composite made from carbon fibres mixed with polymer resin.
Pros - good strength to weight ratio, tensile strength, rigid, compression bearing, lightweight, load bearing
Cons - expensive, one colour, specialised manufacturing process, cannot be repaired easily
Uses - aircraft, sports equipment

Question 18

Liquid crystal displays definition, pros, cons and uses

Answer 18

organic, carbon-based compounds that have both liquid and solid crystal characteristics. Very little voltage is required so less power. Ideal for portable electronic devices

Question 19

Quantum tunelling composites definition, pros, cons and uses

Answer 19

when relaxed is a perfect electrical insulator but when is compressed is conducts electricity.
Buttons, sensors

Question 20

What are the other smart materials

Answer 20

thermochromic liquid crystals (similar to pigment - forehead thermometer), piezoelectric crystals (electric current applied = expands, or mechanical stress into electrical current), smart ink (mimics ordinary paper with ink - easier on the eyes and to read from all angles - kindles)