Polymer chemistry terminology

Polymer chemistry terminology The following is a very simplified explanation. Polymers can be made up of carbon (C), hydrogen (H), chlorine (Cl), fluorine (F), oxygen (O), and nitrogen (N). These six elements, either naturally or synthetically, first form rather simple... 

With the increased use of enzymes in polymer chemistry, the enzymology terminology to describe the reaction kinetics and the enantioselectivity of a reaction has become more and more common in polymer literature. The parameter of choice to describe the enantioselectivity of an enzyme-catalyzed kinetic resolution is the enantiomeric ratio E. The enantiomeric ratio is defined as the ratio of the specificity constants for the two enantiomers, R) and S) (1) ... 

As an example, for styrene at 0°C. the following data are typical (30) rate of polymerization = 14.5%/hour, dose rate = 2.2 X 103 rads/hour, average DP 103. Since 1 rad corresponds to the absorption of 100 ergs/gram of material, it can be demonstrated, on the basis of the above values, that approximately 6 X 105 monomer units are incorporated into polymer for each 100 e.v. of energy absorbed. In conventional radiation chemistry terminology this would be expressed as G(.m0nomer)... 

The held of sol-gel synthesis has blossomed with this approach of chemically modifying the monomers prior to their polymerizahon into a covalently bonded three-dimensional network. This chemistry is reminiscent of traditional organic polymer chemistry where the chemical changes are inflicted on the monomers, which are more labile than the polymer. Hence a polymer can be chemically modihed by constmchng it with modihed monomers. These monomers lend themselves to the usual chemical manipulahons of subshtuhon, elimination, extrachon, purihcation, and so forth. The sol-gel method can be performed at room temperature, another highly attractive synthehc feature. The various sol-gel procedures, terminology, and conditions are summarized in Figure 12.8. 

Many synthetic chemists are reluctant to use polymeric reagents and catalysts because they do not understand polymers, or because they have been educated to believe that polymer chemistry is not pure. The development of polymer chemistry does lag behind that of organic chemistry. But after all, the concept of the macromolecule was generally accepted only around 1930, whereas urea was synthesized first in 1828. Its relative youth helps make polymer chemistry an exciting field of research, wide open for further exploration. For the benefit of readers who lack a fundamental background in polymer chemistry, the overview chapter includes a short section of basic terminology and concepts that should help in understanding the up-to-date reviews of research that follow. 

Obviously, several double bond formation reactions should take place and these reactions should be catalytic ones. Therefore a scheme like scheme 2 is unable to represent adequately the transformation of l,2,3,3-tetraphenylprop-2-en-l-one into polydiphenylacetylene. The main skeleton of l,2,3,3-tetraphenylprop-2-en-l-one is C=C-C=0. If we name the olefin double bond head and the carbonyl double bond "tair (terminology used in polymer chemistry) we can presume three types of propagation steps - head to tail, head to head and tail to tail reactions (Chart 3). 

For polymer chemistry the so-called Purple Book is an important source of information when it comes to nomenclature and terminology in Polymer Science. It is more specific in terminology than the Gold Book, and some definitions may deviate from those given in the Gold Book for well-justified reasons. These are explained in notes to the definition. The (most probably) last hardcopy edition of the Purple Book collects all recommendations until the year 2008. Future editions of the Purple Book are to be expected in electronic form, online accessible, and... 

Before discussing the chemistry and technology of silicone polymers it is necessary to consider the methods of nomenclature of the silicon compounds relevant to this chapter. The terminology used will be that adopted by the International Union of Pure and Applied Chemistry. 

The Commission on Macromolecular Nomenclature of the International Union of Pure and Applied Chemistry has published a nomenclature for single-strand organic polymers Pure and Applied Chemistry, 48, 375 (1976)). In addition the Association for Science Education in the UK has made recommendations based on a more general lUPAC terminology, and these have been widely used in British schools. Some examples of this nomenclature compared with normal usage are given in Table 2. 

In the earlier of the original manuseripts, first published in Pure and Applied Chemistry, whieh make up the chapters of this book, it was the praetiee to cross reference definitions within parentheses as follows (see Definition xx). Whilst beneficial, this led to extensive interruption to the flow of definitions, so throughout this edition of the Compendium of Polymer Terminology and Nomenclature, a practice that is now adopted as standard in the preparation of doeuments under the auspiees of the Subcommittee on Polymer Terminology is used, i.e., terms defined elsewhere in the same chapter are italicized. 

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