• Save
5
Upcoming SlideShare
Loading in...5
×
 

5

on

  • 969 views

 

Statistics

Views

Total Views
969
Views on SlideShare
969
Embed Views
0

Actions

Likes
0
Downloads
0
Comments
0

0 Embeds 0

No embeds

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

5 5 Presentation Transcript

  • Types of Structure
    • When a liquid cools it solidifies
    • The resulting solid may have an orderly structure CRYSTALLINE or POLY-CRYSTALLINE
    Orderly ‘Crystalline’ Structure Shows some irregularity or ‘Poly-Crystalline’ Structure
  • Cooling and Crystal Size
    • Quick cooling results in _________ crystals
    • Slow cooling results in ________ crystals
    SMALL LARGE
  • Non-Crystalline Structures
    • If no orderly structure is present, this is called AMORPHOUS.
    • It is a random structure and this gives it different properties – but what are they..?
  • Amorphous Structures
    • Molecules are arranged randomly – but some regions align…
      • For plastics this gives them extensibility (non reversible)
      • For elastic behaviour in things like rubber, the molecules rotate. This is reversible
  • Plastic behaviour of partly amorphous structure
  • Modelling Amorphous Structures
    • Use spaghetti to model amorphous structures
    • Does a yoghurt pot give any indication that it is made of long chain molecules?
  • Elastic (e.g. Rubber)
  • Young’s Modulus – Amorphous Structures
    • Draw the graph that you think you would get for Stress/Strain for a rubber band
    Strain Stress
  • Young’s Modulus – Amorphous Structures
    • Draw the graph that you think you would get for Stress/Strain for a rubber band
    Strain Stress Molecules ‘lining up’ Molecules fully extended – Less flexible
  • Making Rubber Stiffer
    • Why is some rubber stiffer than other rubber?
    • Would you use the same type of rubber for a car tyre as for a pencil eraser?
  • Vulcanisation
  • Types of Rubber
    • Natural Rubber Vulcanised Rubber
    Stretched Vulcanised Rubber