Flashcards in Mr Oliver F334 - Material Revolution Deck (27)
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1
What is the word used to describe the reactvitiy of a polyalkenes carbon skeleton?
Intert
2
True or false? Polyalkenes are biodegradable?
False
3
What is a nylon?
A Polyamide
4
Why are Polyamides soluble in water?
As they can hydrogen bond as a result of the Nitrogen atom with a lone pair of electrons
5
Why do Polyamides get less soluble the bigger the alkyl group gets?
As this disrupts the hydrogen bonding in the water
6
What is produced in condensation reactions, and is the atom economy 100%?
A small molecule such as HCl or H2O
No
7
What are needed to form a nylon (Polyamide)?
Diamine + Dicarboxylic acid
8
What is the formula of an acyl group?
C=OCl
9
What is created when an amide link is broken by hydrolysis in alkaline conditions?
A carboxylate anion / salt
10
What are the conditions needed to from a Polyester?
Concentrated Sulfuric acid
Heat under reflux
11
What two molecules need to be reacted to form a Polyester?
Carboxylic acid and diols
12
What must the solvent be in recrystallisation?
Soluble in warm tempretures
Insoluble in cold tempretures
13
Describe how recrystallisation occurs
Select a solvent in which the solvent is soluble in warm tempretures, and is insoluble in cold tempretures
Dissolve the mixture in a minimum quantity of hot solvent
Filter the mixture to remove any insoluble impurities
Collect the formed crystals by vaccum filltration and wash them
Dry the crystals in an oven
14
True or false? All apparatus in recrystallisation must be warm
True
15
What, in terms of polymers, does crystalline and amorphous mean?
Crystalline = Ordered regions
Amorphous = Random regions
16
Why do longer polymer chains mean stronger polymers?
As the more tangled they become
The more / stronger the intermolecular bonds are between the chains, and so the chains are less likely to slide over each other, so they are less flexible
17
True of false? The more crystalline a polymer is, the stronger it is?
True
18
What type of poly(ethene) have side branches?
Low density (LD)
19
What conditions are needed to form high density poly(ethene)?
60 degrees, low pressure, TiCl3 catalyst
20
What conditions are needed to form low density poly(ethene)?
200 degrees, 2000atm, no catalyst
21
What is cold-drawing?
A way of increasing crystallinity by stretching polymers
This forms two necks at either side of the polymer
22
What type of bond are made between chains of a thermosetting polymer?
Covalent
23
Can thermosoftening polymers be reshaped / melted
Yes
24
Define a glassy region
If a polymer is cooled to a low tempreture the amorphous regions becomes glassy, and becomes very brittle
25
What is the glass transition tempreture (Tg)?
The point at which when a polymer (with glassy regions) is heated they will be able to move again relative to one another
26
How can the Tg point be reduced?
Co-polymerising PVC (chloroethene) with small amounts of ethenyl ethanoate
27
