HS2004_2339 Week 3 Asyn_Plasticisers and Tg (copy) (copy)

Question 1

What are plasticisers used for

Answer 1

They are everywhere! Used within a lot of common polymers, because if we didn’t a lot of polymers would be too stiff, have less longevity.

Question 2

What are plasticisers

Answer 2

essentially a kind of solvent for polymers. large molecules. don’t dissolve into liquid, but when a polymer has strong side chains that make it stiff, a plasticiser is added, in order to get between the chains and disrupt some of the secondary bonding between chains.
- polymer becomes more flexible. increases in volume, and there is more specific volume, more space. it becomes easier for oxygen and water to access this space. Thalates are a common plasterciser.

Question 3

What is an internal plasticiser

Answer 3

• When a co- polymer is added which has a plasticising effect. makes it more flexible eg has a long side chain or a ring.
• advantages, as the co- polymer is part of the structure, the polymer retains its qualities
• an interference with packing, but unlikely to migrate out of the material, unlike other plasticisers.

Question 4

Disadvantage of added plasticisers

Answer 4

• although they have low volatility, they can migrate to the surface of the material and evaporate. this changes the properties of the plastic.

Question 5

Glass Transition temperature is a s____ o____ transition state, because…..

Answer 5

Tg- point at which a polymer, according to temperate, absorbs energy, begins to vibrate as temp increases, and the polymer softens
- upon cooling, the polymer returns to original state.
- second order transition, as it doesn’t melt, and doesn’t release energy when it returns to its original state.
- polymer structure influences Tg. Highly crystalline polymers, have a high Tg and will often decompose before they soften.

Question 6

Polymer Properties above and below Tg

Answer 6

Question 7

How Tg is influenced by polymer chemistry

Answer 7

Question 8

How the length of side chains on polymers impact Tg, with diagram

Answer 8

• Longer side chains, lower Tg

Question 9

How Tg influences polymers in product design and conservation decision making

Answer 9

Question 10

Paraloid B-72, how dust settles on surface, effect of continuous warm temperatures

Answer 10

Question 11

Particle retention on the surface of paraloid B-72 at room temp vs heated

Answer 11