chapter  1
10 Pages

Polymers

A polymer is a chemical material, or materials, that consists of repeating structural components that are formed through the process of polymerization (Wikipedia, ‘Polymer’, 2013: 1). The word ‘polymer’ comes from the Greek words ‘poly’ to mean ‘many’ and ‘Zeros’ to mean ‘parts’ (Borchardt, 1997: 1230). Shapes of polymer chains, molecules linked together to form a sequence of connected molecules, have several types of geometries beyond the linear polymer chains (Hiemenz and Lodge, 2007: 7). Branched and cross-linked polymer chains are common and arise from the ‘backbone’ of a linear molecule (Hiemenz and Lodge, 2007: 7). The amount of such polymer branching structure is a branching upon branching of a molecule will result in a network type of geometry that is termed cross linked (Hiemenz and Lodge, 2007: 8). Some multi-branched molecules have discrete units and are termed hyper-branched polymers and other multi-branched polymers known as dendrimers, or tree-like molecules (Hiemenz and Lodge, 2007: 8). Co-polymers are repeating units of polymers that have more than one type of repeating polymer unit and a polymer chain that has only a single type of repeating polymer unit is termed homo-polymers (Hiemenz and Lodge, 2007: 9). Also a co-polymer is a series of monomers that repeat in a chain and are bounded by each of their original monomer states (Hiemenz and Lodge, 2007: 9). The tertiary structure of polymer is the ‘overall’ shape of a molecule, and formal polymer nomenclature uses the structure of the monomer or repeat

unit as a system of identification by the IUPAC or the International Union of Pure and Applied Chemistry (Hiemenz and Lodge, 2007: 18). Monomers and repeat units of monomers are the primary descriptive quality of polymers and are categorized in the nomenclature according to the type of structures involved in the monomers (Wikipedia, ‘Polymer’, 2013: 6). Single type of repeating monomers are known as homopolymers, while a mixture of repeat monomers are known as co-polymers (Wikipedia, ‘Polymer’, 2013: 6). The arrangement of monomers in co-polymers is as follows (Wikipedia, ‘Polymer’. 2013: 9-10): Alternating co-polymers: –A-A-A-A-A-A-A-A-A-A-A-A-Periodic co-polymers: –A-B-A-B-A-B-A-B-A-B-A-B-Statistical co-polymers: –A-B-B-B-A-B-A-B-A-A-A-A-Block co-polymers: –B-B-B-B-B-B-A-A-A-A-A-A-Graft co-polymers: –A-A-A-A-A-A-A-A-A-A-A-A-II

B-B-B-B-B-–B-B-B-B-B

Polymer architecture is the microstructure that develops the way the polymers branching points lead to a variation from a linear polymer chain (Wikipedia, 2013, “Polymer”: 7). A branched polymer molecule is composed of a main chain of polymers, and one or more branched sub-chains that form a geometric list of branched polymer forms as follows (Wikipedia, 2013, “Polymer”: 7-8). The physical properties of a polymer are dependent on the size and length of a polymer chain (Wikipedia, 2013, “Polymer”: 7-8) Polymerization is the length of the chain of polymers, and the physical size is also measured as a molecular weight.