Lecture 1: Pharmaceutical Polymers 1

Question 1

Define polymers

Answer 1

Polymers are composed of molecules which have long sequences of one or more species of atoms or groups of atoms linked to each other by covalent bonds.

Question 2

What is functionality?

Answer 2

TWhe number of bonds that a monomer’s repeating unit forms in a polymer with other monomers.

Question 3

What is the minmum functionality that a monomer has in a polymer?

Answer 3

2

Question 4

What happens if you try to polymerise a unifunctional monomer?

Answer 4

Two monomers will react once and not react anymore, so there will be no polymerisation

Question 5

What happens when you try to polymerise bifunctional monomers?

Answer 5

Forms a linear polymer

Question 6

What happens when you try to polymerise bifunctional and trifunctional monomers?

Answer 6

Branched or crosslinked polymers

Question 7

How would you control whether a branched or crosslinked polymer is formed?

Answer 7

By controlling the ratio of bifunctional to trifunctional monomers

More tri = more cross linking

Question 8

What are the main methods of polymerisation?

Answer 8

1. Addition/ freeradical/ chain-growth polymerisation
2. Condensation/step polymerisation

Question 9

What are the 2 main kinds of addition polymerisation?

Answer 9

1. Homogenous polymerisation
2. Heterogenous polymerisation

Question 10

What are the types of homogenous polymerisation?

Answer 10

1. Bulk
2. Solution

Question 11

What are the types of heterogenous polymerisation?

Answer 11

1. Suspension
2. Emulsion
3. Inverse suspension
4. Inverse emulsion

Question 12

What are the different classes of condensation polymers?

Answer 12

It depends on the functional group formed by the heteroatom.
polyETHER
polyESTER
polyCARBONATE -O-CO-O-
polyAMIDE
polyURETHANE -NH-CO-O-

Question 13

How are condesation polymers produced?

Answer 13

Through condensation reactions with monomers containing heteroatoms
The links contain the heteroatoms

Question 14

What is interfacial polymerization?

Answer 14

1. Used in condesation polymerisation
2. Two immiscible solutions poured into a container –> they form separate layers
3. They react at the interface to produce the polymer which is pulled out
4. Used to synthesize nylon

Question 15

Explain the process of addition polymerisation.

Answer 15

1. An initiator molecule is cleaved by UV/ heat/ chemical/ high energy radiation to form a radical
2. The free radical attacks the monomer by breaking the C=C to form a radical.
3. The monomer radicals react and get joined tgt
4. The bigger polymer molecules also form radicals, which allows the polymer to grow.
5. The plolymerisation reaction is terminated by combination or disproportionation.

Question 16

How to differentiate between a head and tail radical?

Answer 16

Head & tail is determined by the stability of the radical that gets formed. The part that forms the more stable radical (the one with more functional groups) is called
the head.

Question 17

Which kind of propagation is more stable and why?
Head to Head
Head to Tail
Tail to Tail

Answer 17

Head to Tail propagation is more probable due to steric factor & greater stability of the subsequent radical.