Material Revolution Flashcards
What reagent will convert a ketone into a nitrile and what are the conditions
HCN in the presence of an alkali
What can be added to polyesters to make them more flexible
plasticisers
What is glass transition temperature
The point where the amorphous regions unfreeze/freeze
Describe the solubility of amines
Can dissolve in water as it can form hydrogen bonds, the smaller the molecule, the more soluable
What is a nucleophile?
A nucleophile is a species (either a negatively charged ion or a negative region in a polar molecule) which is attracted to a positive site in another substance. All nucleophiles contain an active lone pair of electrons
What is a proton acceptor known as
A base
How do amine’s lone pair affect it’s properties
Soluble in water, has base and nucleophile properties, ligand behavious
Do amines act as bases or acids and why
They are bases because they accept protons
What is a condensation reaction
Where two molecules have joined together to form a larger molecule with the elimination of a smaller molecule
Describe the process of recrystallisation
The chosen solvent dissolves salt well at higher temp but very little / none at room temp
method:
1. use hot solvent
2. dissolve in minimum amount of solvent
3. leave to crystallise/cool
4. filter off crystals, (soluble) impurities are left in filtrate /
solution
5. wash with (cold) solvent and dry
what is meant by Tg
the temperature below which a polymer turns glassy
Why would a polymer with less crystalline regions be more flexible
chains are further apart so has weaker intermolecular bonding so chains in can move over one another more easily
How should you describe the absorption peak made by an OH bond
Broad
Describe the properties of a polymer at temperatures above its Tm.
Where the polymer melts above that temp
Describe and explain the properties of a polymer at temperatures
below its Tg.
polymer becomes brittle
because chains cannot move over each other so break when a force is applied
