Polymer science involves several scientific disciplines—organic chemistry, colloidal science, and biochemistry. Polymer molecules, including plastics, resins, proteins, lattices, and nucleic acids, fall into the category of high-molecular-weight species composed of repeating units of smaller molecules. These substances have in common an origin of natural or synthetic organic sources.
Plastics and Particle Size Measurement discusses how all of the materials termed plastics have in common a process whereby a small molecule (monomer) under proper conditions can be linked to identical or similar molecules to produce a very large molecule (polymer). In some applications, the polymer is produced in the form of pieces, or pellets. The particle size of the pellets contributes significantly to processibility of the polymer. Flowability from the hopper and melting rate when heated, have a direct effect on process speed.