The Time Project Lesson 4: Plastics (Thermoplastics)
Home Thermoplastics Thermosetting plastics Plastic Memory Table of plastics Programmes of study	Thermoplastics Thermoplastics are made up of lines of molecules with few cross-linkages. This allows them to soften when heated and to be bent into a variety of shapes and forms. They become stiff and solid again when cold. This process can be repeated many times. Long chain molecules The molecules of thermoplastics are in lines or long chains with very few entanglements. When heat is applied the molecules move apart, which increases the distance between them, causing them to become untangled. This allows them to become soft when heated so that they can be bent into all sorts of shapes. When they are left to cool the chains of molecules cool, take their former position and the plastic becomes stiff and hard again. The process of heating, shaping, reheating and reforming can be repeated many times.	Useful links Introduction Situation & Brief Orthographic Drawing Brain Storming Plastics Theory Woods Theory Metals Theory Drawing Styles Tools used Flowcharts Vacuum Forming Quality Control Finishes Teacher's Rationale Programmes of Study

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