Copolymers source-based method

Source-based Method. The source-based structural representation of a copolymer is in the format (A-B -)a , where A, B, etc, are monomers. Figures 6-8 illustrate the method. 

Over a period of about 50 years, representation of polymer structures, both on paper and in databases, has developed from a virtually random system to a highly organized and sophisticated one. Polyoners are represented sometimes by structure-based methods, sometimes by source-based methods, and sometimes by both. Both methods survive because each offers advantages and disadvantages. Both methods involve structural representation of polymers by a precisely defined set of rules developed over several decades by CAS, lUPAC, and the Committee on Nomenclature of the Division of Polymer Chemistry of the ACS. Areas still in need of improved representation are copolymers of imterminated SRU types aftertreated (post-treated) polymers, and dendritic (52), hyperbranched, hyper-cross-linked, star, and star-block polymers. Also needed are hierarchical relationships between intellectually related polymers (53). 

Structure-based Method. CAS does not generally index unterminated copolymers of SRUs by the structure-based method. Formats such as poly(oxyethylene)/poly(oxytetramethylene) or poly[(oxyethylene)/ (oxytetramethylene)] are not used. Instead, a source-based representation is used (see Fig. 9 below). 

Scheme 12.3 Preparation of a PEO-based azo triblock copolymer by a modified ATRP method. Source Reproduced from Yu et al., 2005c.

The polymers described in this chapter are industrial-grade materials, and consequently some of the examples may contain additives and/or may be chemically modified. Polymers in various morphological forms may be analyzed, and these include films, fibers, solid pelletized and powdered products, and dissolved/dispersed materials in liquids such as paints and latex products. Also, the same base polymer, such as a styrene-butadiene copolymer, for example, may exist in a rubber, a resin, or a plastic. In general, reference will not be made to the original source of the polymer samples. Because infrared spectroscopy is more widely used than the Raman method, the authors will focus more on the applications of this technique. However, the Raman method, which is complementary to the IR method, does have important and unique applications in the polymer analysis, especially with regard to the determination of the fundamental polymer structure and its... 

However, VDF-IDT-CRPs always require a free radical source (e.g., butyl peroxide (TBPO)), as direct metal catalyzed initiation from perfluoroiodides or any other halides is not available. This is a serious drawback with respect to the precise synthesis of block or graft copolymers based on FMs, as such systems would inevitably lead to mixtures of homo- and copolymers with the current technology. Therefore, the availability of an initiation method directly from halides, most likely mediated by transition metal catalysis, would be highly valuable. 

For this third generation of manufactured protein fibers, milk and soy beans are the two most important protein sources. Chicken feathers also are being widely used in the development. In addition to the common methods used in the first and second generations, many technical innovations have been applied to the production of these manufactured protein fibers. Examples include the use of biochemistry to modity the protein structure, the incorporation of synthetic polymers to improve the fiber strength and modulus, the formation of protein-based copolymers by chemical grafting, etc. 

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