scroll to top
Stuck on your essay?
Get ideas from this essay and see how your work stacks up
Word Count: 1,141
Addition Polymerisation The joining of two or more simple molecules or monomers to form a new compound a polymer which has the same empirical formula Mechanism of the Polymerisation of Ethene Thousands of ethene molecules join up to form a type of polyethene known as low density polythene CH2CH2n CH2-CH2 n number of joining molecules can vary from 200-2000 fig 1 The mechanism is known as a free radical reaction as it is the radicals which initiate the three stage process of polymerisation Stage 1 Initiation by free radicals R l H2CCH2 R CH2 CH2 l where r is the radical new radical Fig 2 Stage 2 Propagation Each time a radical hits an ethene molecule a new longer radical is formed R CH2 CH2 l H2CCH2 R CH2 CH2 CH2 CH2 l R H2 CH2 CH2 CH2 l H2CCH2 R CH2 CH2 CH2 CH2 CH2 CH2 l Fig 3 Stage 3 Termination Eventually two radicals combine and the process stops as no new radicals are formed 1 As the chains grow by radical mechanism it is possible for a radial exchange to occur to give a radical within the chain 2 By this mechanism the chains can become more
@Kibin is a lifesaver for my essay right now!!
- Sandra Slivka, student @ UC Berkeley
Wow, this is the best essay help I've ever received!
- Camvu Pham, student @ U of M
If I'd known about @Kibin in college, I would have gotten much more sleep
- Jen Soust, alumni @ UCLA