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[koraltptp]

Hi,

 

I will do polymerisation of monomers via emulsion polymerisation method.

I went through many text books related to this procedure. And they all says the key ingredients are 

1) monomer, immiscible to water,

2) surfactant,

3) initiator, water-soluble and

4) water.

 

***********Steps in procedure:

1) First monomer and water is mixed and stirred to have small droplets of monomer dispersed within water.

2) Then, surfactant diluted in water.

It is mixed to monomer/water mix.

So, surfactant molecules, surround monomer droplets and form micelles (particles).

3) Then, initiator is dissolved in water, and is separated to its ions. 

Radicals of initiator diffuses in particles from water-phase, and starts polymerisation.

4) Simultaneously, more monomer diffuses in particle, and keeps polymerisation going on.

5) Another Initiator radical gets in particle, and terminates polymerisation.

*************

 

My other questions related to above procedure:

 

#1 : When I read an example procedure , they use one more ingredient, it is activator. 

What does activator exactly do during steps described above ?

How does it contribute to polymerisation ?

 

#2 : How all droplets (particles) can have uniform sizes ?

I guess this will effect mol. weight distribution in end polymer.

 

#3 : Why initiator terminates the polymerisation ?

 

#4 : Does Initiation/termination of polymerisation within particle is an indefinite switch on/off process ? 

 

Thanks for the answers in advance.

 

[breizh]

https://tel.archives...e_Delaittre.pdf

 

 

let you consider this thesis , unfortunately  in French !

 

Breizh