percentages of head to- tail and head-to-head linkages in the poly(vinyl acetate).

1. Poly(vinyl acetate) of number-average molecular weight 100,000 is hydrolyzed to
poly(vinyl alcohol). Oxidation of the latter with periodic acid to cleave 1,2-diol
linkages yields a poly(vinyl alcohol) with X n = 200. Calculate the percentages of head-
to-tail and head-to-head linkages in the poly(vinyl acetate).
Solution:




Repeating Unit: = 86.09 g/mole

100,000
 PVA initial X n =
86.09

n oxidation generates n + 1 fragments

1162
Thus Number of oxidation = −1
200

= 4.81

In other hand, the initial X n drops to 200 with addition of acid. On average, the present

molecule is cleaved to form 5.81 smaller molecules, so it is cleaved at 4.81 diol linkages.


 The percent head-to-head: = 4.81 100% = 0.41%
1162