Page 13 - POLYMER TECHNOLOGY

1.8 Molecular Weight

The molecular weight of a polymer is the total atomic weight of the individual atoms
that make up the molecule. This indicates the average length of the bulk resin
polymer chain. All polymer molecules with a certain grade do not have the same
molecular weight. There is a range or distribution of molecular weights because
during polymerization process not all chains in a polymer grow to the same length.
The molecular weight distribution in a polymer describes the relationship between
the number of moles of each polymer and the molar mass of the polymer.

Molecular Weight, M=Mass of a mole of chains.

1.9 Degree of Polymerization

The degree of polymerization (DP/n), is the number of monomer unit in a polymer
molecule.

Degree of polymerization provides the indirect method to determine the molecular
weight.

1.10 Polymerization Process

Polymerization process is a chemical reaction process to combine monomers unit to
form a long chain molecule (macromolecule) called polymer. There are two type of
polymerization, Additional Polymerization and Condensation polymerization.
a. Additional Polymerization (Chain Growth Polymerization)

An additional or chain growth polymerization is a polymer formed by chain addition
reactions between monomers that contain a double bond. During polymerization
process there is no by-product produced.

9 | P a g e