The repeat unit for poly vinyl alcohol PVA is shown below Ca

The repeat unit for poly (vinyl alcohol) (PVA) is shown below: Calculate the repeat unit molecular weight for PVA. If the degree of polymerization of a particular PVA is 2,000. Determine the number-average molecular weight of this particular polymer.

Solution

a) Each repeat unit of PVA has 1 oxygen, 2 carbons and 4 hydrogens. Hence,

m = 1(O2) + 2(C) + 4(H)

= 15.9994 g/mol + 2(12.0107 g/mol) + 4(1.0079 g/mol)

= 44.0524 g/mol

b) Since, the degree of polymerization of a particular PVA is 2000, The number-average molecular weight of this particular polymer is

M = 2000 * 44.0524 g/mol

= 88104.8 g/mol