Principles of Polymers and Polymerization

Polymeric materials are based on both precise control of molecular structure through polymerization and subsequent processing techniques. The necessary requirements for designing and processing of polymeric materials are functionality, composition, topology, and chain uniformity. The structure of polymer materials consists of designed architectures and this property helps accomplish various applications. 

Polymers are macromolecules built up by large numbers of much smaller molecules called monomers. Because of the increased reliability of polymeric materials, they are extensively used in many applications. 

Polymers can be classified according to one or more of the following criteria  

Chemical Nature of Monomers Monomers contain the following [1]  

One or more pairs of double bonds such as C=C and C=0 can form polymers by conversion of their double bonds into saturated linkages for example, vinyl chloride can undergo free-radical addition polymerization to form polyvinyl chloride. 

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Figure 15.8 Principle of synthesis and polymerization of difunctional benzoxazines, using the example of B-a and the resulting crosslinked polymer PB-a.

In this manuscript we review the principles of bulk and solution polymerization with particular emphasis on high conversion (high polymer concentrations) rate of polymerization and molecular weight development. 

ThF Tadros. Polymeric surfactants , stabilization of emulsions and dispersions. In E Desmond Goddard, JV Gruber, eds. Principles of Polymer Science and Technology in Cosmetics and Personal Care. New York Marcel Dekker, 1999, pp 73-112. 

In the 1940s and 1950s, random branching in polymers and its effect on their properties was studied by Stockmayer, Flory, Zimm and many others. Their work remains a milestone on the subject to this day. Flory dedicated several chapters of his Principles of Polymer Chemistry to non-linear polymers. Especially important at that time was the view that randomly branched polymers are intermediates to polymeric networks. Further developments in randomly branched polymers came from the introduction of percolation theory. The modern aspects of this topic are elaborated here in the chapter by W. Burchard. 

However, we shall first briefly consider the main kinetic principles of epoxy compound polymerization under the action of TA and the structural peculiarities of the resultant polymers. 

Other things that are particularly controlled in condensation polymerization are chain topology and cascade reactivity of monomers. In general condensation polymerization, not only linear polymers but also cyclic polymers can be produced because both ends of the polymer are reactive during polymerization. When cascade reactions selectively occur on a monomer, condensation polymerization proceeds in a way different from general polymerization behavior based on the principle of Carothers and Flory. Thus, in condensation polymerization of AA and BB monomers, if AA monomers successively react with both the functional groups on a BB monomer, a poly-... 

Mixing principles are relevant to many disciplines what makes mixing polymeric materials unique is their exceptionally high viscosity. There are numerous texts (1-5) that are entirely devoted to the complex problem of mixing of polymers and plastics, and we refer the reader to them for further reading. 

A number of terms unique to polymerization are discussed in Sec. 7 of this Handbook. A general reference on polymerization is Rodriguez (Principles of Polymer Systems, McGraw-Hill, 1989) and a reference guide on polymerization reactors is available by Gerrens [German Chem. Eng. 4 1-13 (1981) ChemTech, pp. 380-383, 434-443 (1982)] and Meyer and Keurentjes (Handbook of Polymer Reaction Engineering, Wiley VCH, 2005). 

It is from these perspectives that we have reviewed the pulse radiolysis experiments on polymers and polymerization in this article. The examples chosen for discussion have wide spread interest not only in polymer science but also in chemistry in general. This review is presented in six sections. Section 2 interprets the experimental techniques as well as the principle of pulse radiolysis the description is confined to the systems using optical detection methods. However, the purpose of this section is not to survey detail techniques of pulse radiolysis but to outline them concisely. In Sect. 3, the pulse radiolysis studies of radiation-induced polymerizations are discussed with special reference to the initiation mechanisms. Section 4 deals with applications of pulse radiolysis to the polymer reactions in solution including the systems related to biology. In Sect. 5 reaction intermediates produced in irradiated solid and molten polymers are discussed. Most studies are aimed at elucidating the mechanism of radiation-induced degradation, but, in some cases, polymers are used just as a medium for short-lived species of chemical interest We conclude, in Sect. 6, by summarizing the contribution of pulse radiolysis experiments to the field of polymer science. 

McCrum NG, Read BE and Williams G, "Anelastic and Dielectric Effects in Polymeric Solids", Wiley, New York, 1967. McCrum NG, Buckley CP and Bucknall CB, Principles of Polymer Engineering", Oxford University Press, Oxford, 1988, 2nd Ed, 1997. 

FIGURE 4-17 Graph of Rp versus [M][/],/z (plotted from the data listed in P. J. Rory s book, Principles of Polymer Chemistry, for the polymerizations involving methyl methacrylate and styrene). 

As in so many things in this field, if you want to work through the arguments yourself, you cannot do better than go to Flory— see Principles of Polymer Chemistry, Chapter EX. Stockmayer s equation illustrates the point we wish to make with dazzling simplicity as f the number of branches, increases, the polydispersity decreases. Thus for values of/equal to 4, 5 and 10, the polydispersity values are 1.25, 1.20 and 1.10, respectively. Note also that for / = 2, where two independent chains are combined to form one linear molecule (Figure 5-28), the polydispersity is predicted to be 1.5. Incidentally, an analogous situation occurs in free radical polymerization when chain termination is exclusively by combination. 

Chapter 14 provides the basic principles of polymer science, and addresses the importance of this subject. This chapter aims to give a broad and imified description of the subject matter—describing the polymerization reactions, structures, properties, and applications of commercially important polymers, including those used as plastics, fibers, and elastomers. This chapter focuses on synthetic polymers because of the great commercial importance of these materials. The chemical reactions by which polymer molecules are synthesized are addressed along with the process conditions that can be used to carry them out. This chapter also discusses topics on degradation, stability, and environmental issues associated with the use of polymers. 

We begin with a description of the high-pressure polymerization process since it is an authentic example of how the principles of thermodynamics and kinetics can be combined with creative engineering to develop an economically viable high-pressure process. These principles can be generalized and extended to other high-pressure processes. After describing the polyethylene process, we move on to more recent work on polyethylene and ethylene copolymers, followed by a discussion of other recent SCF studies with a variety of other polymers and monomers. 

G., Principles of Polymerization, John Wiley, New York, 1991 Rertipp, P. and Merrill, E. W., Polymer Synthesis, Hiithig Wepf, Basel, 1986 Rbdriguez, F., Principles of Polymer Systems, Tata McGraw-Hill, New Delhi, 1974 Rudin, A.,... 

The previously discussed principles of grafting-to and grafting-from can also be applied for the modification of polymer surfaces with polymer brushes. However, the binding of linkers and polymerization initiators to polymer surfaces is not as straightforward as it is for oxidic inorganic materials. Thus, dedicated pretreatments are usually necessary. These may include rather harsh reaction conditions due to the chemical inertness of many polymers (see Chapter 3). Alternatively, radiation treatment of polymers (to form radicals) followed by exposure to air may be used to form peroxides and hydroperoxides, which can be directly used as initiators for thermally or ultraviolet-induced graft polymerizations [16,17] (see Chapter 2). 

Zhang, M., June, S.M., Long, T.E., 2012. Principles of step-growth polymerization (polycondensation and polyaddition). In Matyjaszewski, K., Moller, M. (Eds.), Polymer Science A Comprehensive Reference, vol. 5. Elsevier, Amsterdam, pp. 7-47. 

P.J. Flory, Principles of Polymer Chemistry, Chapters 2,3,8, and 9, Cornell University Press, Ithaca, New York, 1953 P.EA1. Allan and C.R. Patrick, Kinetics and Mechanism of Polymerization Reactions, Chapter 5, Wiley-Interscience, New York, 1974. 

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