ABSTRACT
The first task in the description of a macromolecule is to enumerate all the atoms. The results can be summarized as a set: {
A
}. The molecular weight
M
for the polymer can be then be calculated as:
(2.1)
where the sum is over all
N
atoms in the molecule and
M
is the atomic weight for each atom. Although there are many macromolecules, especially biopolymers
,
for which the value of
N
is unique, many other macroscopic samples of polymeric material are characterized by a distribution of
N
and hence of
M
. The concept of a molecular weight distribution
,
ρ
(
M
), is central to the modern practice of polymer science. The consequences of such a distribution will be considered throughout this book.
