This chapter discusses the properties and characterization of polymers. The techniques most commonly used to determine polymer molar mass include end-group analysis, osmometry, light scattering, ultracentrifugation, sedimentation, viscometry, and chromatography. However, most of these involve rather lengthy procedures and in practice molar masses are obtained from high performance gel permeation chromatography (HPGPC) or viscosity measurements. It is important to recognize that the fundamental measurements of molar mass must be performed on dilute solutions so that intermolecular interactions can be ignored. The chapter then looks at polymer stereochemistry; structure-property relationships; and polymer processing. It also considers the thermal methods of polymer analysis, in which some physical property of a substance is measured as a function of temperature or time while the substance is subject to a controlled temperature programme. The most common techniques are differential scanning calorimetry, thermal gravimetry, dynamic mechanical analysis, dilatometry, heat-deflection temperature, and melt index.
Chapter
Polymer properties and characterization
Book
David J. Walton and J. Phillip Lorimer
Polymers gives a thorough introduction to polymer chemistry, ranging from a historical perspective, through the development of high-tonnage materials earlier in the twentieth century, to modern high-performance materials that have a range of useful additional properties. Polymers are the archetypal modern materials, used in every aspect of everyday life. Chapters cover polymers, polymer properties and characterisation, chain polymerisation, step-growth polymers, three-dimensional networks, and functional polymers. The text also includes discussion of practical industrial aspects in the technology of these materials.
Chapter
Introduction to aminoacids and proteins
This chapter introduces proteins as biological polymers that play important roles in the chemical processes of life and represent 15% of the total cell mass. It explains the chemistry of amino acids and how their properties change when they are polymerized in a protein, which are important in the analysis of the molecular basis of the is properties of proteins. It also describes proteins as linear polymers that are derived from α-amino acid monomers, noting that α-amino acids are carboxylic acid with an amino group, a hydrogen atom, and a further substituent attached to the α-carbon. The chapter looks at the distinguishing feature of proteins as they are composed of a variety of monomer units linked together in a defined sequence. It analyses the variety of possible proteins that underpins the diverse roles for which they are suited.
