DT THEORY

➢ MAHOGHANY

________: rich, dark red in colour, wood is expensive, contains interlocking grain, nice surface finish.

PVC

______WEATHER_ resistant, chemical resistant, gas impermeable, however forms HCL when broken down- toxic to environment.

When reheated they can not soften due to the ________ forming rigid cross links which can not break.

polymer chains

ZINC

________: Low melting point, weak material Very resistant to corrosion Uses: a coating on screws, steel buckets and to galvanise steel.

thermoplastic

a material which can only be heated and shaped once.

ALUMINIUM

________: lightweight, ductile, malleable, corrosion resistant, electrical and thermal conductor Uses: drink cans, aircraft bodies, bike frames, window frames, saucepans, cooking utensils, etc.

Linen

________: cool to wear, breathable, lightweight, high durability, creases badly, etc.

Box Board

multiple layers of pulp, good printing surface, can be creased, embossed, etc.

Hardboard

compressed wooden fibres, similar to mdf but denser and stronger.

MILD STEEL

________: Ductile and malleable, high tensile strength, tough, poor resistance to corrosion.

LIQUID CRYSTAL DISPLAY

________: LCD change colour when an electrical voltage is applied to it- the cells turn from light to dark.

ALLOY

________: Metals made form two or more elements to achieve desirable traits such as aesthetic appearance, conductivity, strength, ductility, etc.

Polyester resin PR

________: rigid, heat resistant, brittle Uses: castings, used in layering process for GRP for boat hulls.

Urea formaldehyde

________: hard, heat resistant, good electrical insulator, brittle.

THERMO CERAMICS

________: A metal powder is placed within a mould or die under high pressure, causing particles to fuse and bond with each other.

JELUTONG

➢ ________: Fine texture, straight grain, easy to cut, sand and carve, brittle, white or straw coloured.

Cotton

________: good absorption, breathable, low elasticity, tends to crease.

Polypropene

________: Doesnt absorb moisture, good chemical resistance, lightweight, not very breathable, flammable, cant be ironed.

CARBON FIBRE

________: ________ filament woven into a fabric set into a polyester resin matrix.

▪ THERMOCHROMIC MATERIAL

________: changes colour according to the temperature its subjected to.

Wool

________: warm to wear, absorbent, dries slowly, can shrink, not durable, good flame resistance.

➢ OAK

________: A very strong, hard, tough wood, good weather resistance, open grain.

Display

________ for the user: digital clocks, watches, computer screen, etc.

Nylon

________: warm to wear, absorbent dries slowly, crease resistant, not very breathable, can create static electricity.

Polyester

________: non absorbent, dries fast, good elasticity, can be recycled, low warmth.

Epoxy resin ER

________: Rigid, clear, hard, tough, chemical resistant Uses: Adhesives, surface coatings, encapsulation of electrical components, cardiac pacemakers.

TIN

________: Ductile, malleable, low melting point, corrosion resistant Bright silver appearance Uses: coating on food cans, ________ foil, soft solder.

MEDIUM FIBREBOARD MDF

________: compressed wooden fibres /dust with PVA Advantages: Available in large sheets at variable thicknesses, MDF has no grain, cheaper than most materials, consistent strength in all directions.

O Neoprene

________: good thermal resistance, toughness, good oil and chemical resistance.

COPPER

________: Good conductor, ductile, malleable, creep resistant.

➢ BEECH

________: Tough, close grained, hard, light in colour, beech is also very easy to work with.

PLYWOOD

_____:thin layers of wood placed at 90 degree to each other and compressed with UF resin.

➢ CEDAR

________: A pale yellow colour, fine even texture, lightweight, low density, cant corrode metals.

O ELASTOMER

________: Materials which at room temperature can be deformed under pressure and then upon release will return to their original shape.

▪ PHOTOCHROMIC MATERIAL

________: changes colour with light intensity, photochromic paints contain pigments which change colour according to the uv it is subjected to.

HARDWOOD

________: A hardwood is a type of wood originating from a deciduous tree, generally much more expensive than softwoods due to them taking about 100 years to mature.

REACTIVE GLASS

________: ________ is a smart glass, changes in response to temperature fluctuations by changing the tint of the material.

➢ LARCH

________: hard, tough, attractive grain a pattern, resistant to rot when in contact with the ground.

❑ Foil

________ lined board: board with foil applied either one side or both sides, provide water resistant and heat insulating layer.

Flame resistance

________: dipped in chemicals to create a barrier between the fibre the flame.