ABSTRACT
You will recall from your elementary organic chemistry that the physical state of members of a homologous series changes as the molecular size increases. Table 3.1 briefly outlines this for members of the alkane series with the general formula [C
H
]. From Table 3.1, it is obvious that moving from the low-to the high-molecular-weight end of the molecular spectrum, members of the series change progressively from the gaseous state through liquids of increasing viscosity (decreasing volatility) to low melting solids and ultimately terminate in high-strength solids. Polymers belong to the high-molecularweight end of the spectrum. In the following discussion, we will attempt to illustrate how the unusual properties of high polymers are developed. To do this, it will be convenient to consider the chemical and structural aspects of polymers at three different levels:
1. The chemical structure (atomic composition) of the monomer (primary structure) 2. The single polymer chain (secondary level) 3. Aggregation of polymer chains (tertiary structure)
But before we proceed into extensive discussion of these aspects, we must first consider the molecular forces operative in polymers. After all, this is fundamental to understanding polymer structures.
