Volumetric Properties

This chapter discusses the densimetric and volumetric properties of polymers, especially density and its variations as a function of temperature and pressure. Density is defined as the ratio of mass to volume. This chapter begins with a description of fundamental quantities of mass and volume. Under this, it considers the molar mass of polymeric structural units and of structural groups and Van der Waals volumes of structural units and structural groups. The concept of zero point density based on the extrapolation of densities of crystalline and liquid substances to 0 K is also explained. Following this, the chapter deals with standard molar volume and density (at room temperature), based on which, it describes molar volumes of organic liquids at room temperature, molar volumes of rubbery amorphous polymers, molar volume of glassy amorphous polymers, molar volumes of crystalline polymers, and molar volumes of semi-crystalline polymers at room temperature. Furthermore, it explains the phenomenology and theory of thermal expansion, also shedding light on the general expressions for the molar volumes as a function of temperature. Finally, it deals with isothermal expansion.