Chapter 9: Reaction Mechanisms, Pathways, Bioreactions and Bioreactors

Example 9.4: Calculate Xn for Monomers with the Same End Groups

Initially we have 10 polymer molecules of ARA and 10 polymer molecules of BR¢ B, for a total of 20 structural units (10 R and 10R¢ ), a total of 20 A functional groups and 20 B functional groups. At time t there are seven polymer molecules and the distribution of molecules at time t is shown in the table below. Calculate the fractional conversion of functional groups, p, and the number average chain length .

Molecules at time t
Structural Units(SU)
ARA
1
BR' B
1
ARR' B
2
ARR' RR' B
4
ARR' RR' RR' B
6
ARR' RA
3
BR' RR' B
   3   

20 SU

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Solution

MA0 = Number of functional groups of A initially = 20

MA = Number of functional groups of A remaining = 7

N0 = Number of polymer molecules initially.

N = Number of polymer molecules remaining at time t

or



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