Question

answer the following questions:

a. how does the N,N,N',N'-tetramethylenediamine activate the radical initiator, the ammonium peroxodifulfate?

b. Describe briefly a generic mechanism for a radical polymerization?

Answer 1

(CH3)2NCH2CH2N(CH3)2 is Tetra methyl ethylene diamine(TMEDA).This compound is used in the polymerization process,while preparing gels like polyacrlamide,along with the catalyst Ammonium

persulphate.Initiation of acrylamide polymerization will begin with the help of free radical formed from

TMEDA along with the radical formed from persulphate. Thus TMEDA helps vinyl polymerization initiation and amino groups are present in

the polymer as endgroup.

2.Free radical polymeriztion is

a kind of chain

reaction.consists of the

following steps .
a.Initiation.it is done by the generation of monmer units with active centers,ie radicals most commonly found in vinyl compounds and carbonyl compounds eg;CH2=CH2----> .CH2-CH2.
b.Propagation
IN this step ,polymerization will continue,by increasing chain length.CH2-CH2+CH2-CH2-------->ch2-ch2-ch2-ch2. and the process will continue.
c.Termination
IF we keep initiator concentration at optimum level ,we can produce plymer of desired molecular weight.By combining to active long chain we can terminate the polymerization
n--(ch2-ch2)-- ----->---(ch2-ch2)--n
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