The chapter "Polymer Chemistry" from the National Cancer Institute's NCI Thesaurus defines polymer chemistry as the study of the synthesis and application of polymers. Polymers are high molecular weight compounds, both natural and synthetic, consisting of millions of repeated units, each a relatively simple molecule.The chapter "Polymer Chemistry" from the National Cancer Institute's NCI Thesaurus defines polymer chemistry as the study of the synthesis and application of polymers. Polymers are high molecular weight compounds, both natural and synthetic, consisting of millions of repeated units, each a relatively simple molecule.