Plasticization, high molecular weight macromolecule

To conclude this section on polymols, we should note that we have used the term polymer almost exclusively to refer to organic macromolecules. The term plastic refers not only to organic substances of high molecular weight, but also to such substances that at some point in their manufacture have been shaped by flow. Thus, the term plastic is more specific than the term polymer, and this term carries with it an indication of its processing history. As we will see in Chapter 7, there are many materials that can be considered polymers, yet are formed by routes other than melt processing. 

Polymeric macromoleculcs of types V-VII are needed for applications requiring enhanced molecular siite (see also Chap. III). Thus, linear polymers of type V are prepared by Mannich polymerization or from bis-Mannich bases by exchange reaction, for example, with bis-thiols, as in the case of poly(ketosulfide) 501, which is useful as a high-molecular-weight antioxidant in the processing of plastics.Macromolecules of type VI are generated by the functionalization of polymers, as shown by 502, which is obtained by aminomethylation of polyacrylamide and used as flocculant in water treatment." - ... 

Acetal homopolymer was the result of R. N. MacDonald s pioneering discovery in 1952 of a stable, high molecular weight poljnner of formaldehyde [4]. MacDonald s search and discovery has antecedents in Butlerov s description of formaldehyde polymers in 1859, Du Font s entry into the plastics industry in 1915 [5], Staudingers monumental work on macromolecules beginning in 1922, Carother s work which led to the discovery of nylon and its commercialization in 1938 and Barkdoll s work on the purification of monomeric formaldehyde and its chemistry in 1948. 

Most commercial plastics, also known as resins in North America, are based on the element carbon and are synthesized, or made, from simple, oil-based raw materials. These starting materials are called monomers and these simple, low molecular weight materials are put together, by a process known as polymerization (polymerisation), so as to form polymers. This term means that the final product consists of many identical, repeat units. Because the final molecular weight, or mass, is so large the material may also be referred to as a high polymer or, as a macromolecule . 

Polymerization, bulk Also called mass polymerization or step-growth polymerization. It is from undiluted low molecular weight starting materials. It is the simplest and oldest method for the synthesis of macromolecules. This method has a reaction, which is relatively simple, and rapid, plastics of high purity are formed, and the plastics obtained are immediately processable. Basically, the polymerization process involves only monomer and polymerization initiator or catalyst. It is carried out in the absence of a solvent or other dispersion media. This technique is applicable to both addition and condensation polymerization. Fundamentally differences exist. 

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