The engineering principles that apply to polymerization reactions are extensions of well-established principles
for the study of reactions that involve small molecules. Macromolecules are very attractive, because, through
changes in their molecular architecture, one can influence end-use properties that small molecules do not
have, such as melt strength, crystallinity, and clarity, to name a few. This additional degree of freedom comes
at a cost, however, because it introduces a level of complexity that requires careful consideration during
reactor design, analysis, and/or operation. There are many practical problems in polymer reaction engineering
that can be handled using traditional tools. Very little additional expertise is required from reaction engineers.
There are other problems that demand this expertise and, because they do, it becomes more difficult to avoid
empirical components and determine when an observation should be predicted by the model or handled as a
measurement artifact. This review attempts to define the borders that separate these two types of problems
and discusses the challenges and opportunities industry often faces. There are still practical problems to solve
in the area of commodity polymers, and there are many opportunities to apply the same engineering principles
to specialty polymers.