Chapter 1 - Plastics Flashcards
Long-chain molecule
The main constituent part of a polymer. The long-chain molecule is made up of a series of atoms - in the case of the hydrocarbons, these would be made up of hydrogen and carbon along with elements such as oxygen
Polymer
The proper term of a plastic material
Cellulose
A constituent part of timber. Approximately 55% of a tree is made up of cellulose. NB. This material can be used to produce a cellulose-based polymer.
Heat treatment
A term given to a range of processes using heat to cause a change in a metal’s properties by making changes to the internal structure of the material. Annealing, hardening, tempering and normalising are the more common heat treatments
Biodegradable
A term given to materials that will break down with the aid of natural processes such as sunlight and rain
Renewables
Materials that are extracted from managed sources, such as Scandinavian pine taken from forests where trees are replaced by saplings as they are felled.
Biopol
A polymer made from natural cellulose, which can be used to make biodegradable packaging.
Degradation
The deterioration of polymers
Injection moulding
A method of processing thermoplastic materials. Products generally have complex 3-D shapes.
Blow moulding
A process of manufacturing thermoplastic materials into re-entrant shapes with a single opening. Examples include soft drinks bottles, detergent bottles, etc.
Parison
The extruded tube of thermoplastic material used in the process of blow moulding
Rotational moulding
A method of moulding thermoplastic polymers that involves plastics in powder form taking the shape of a fully enclosed mould as the mould passes through a heating section. The material becomes rigid as the mould is cooled.
Cycle time
The time it takes to complete an operation within a production process
Texture
The ‘feel’ of the surface of the material; can range from extremely smooth through patterned, to very rough, e.g. for grip.
Thermoforming
A form a vacuum forming. The main differences are that air pressure and an additional female mould assist the forming process to enable greater detail to be achieved.
