Applications for Synthetic Polymers

Many important fibers, including cotton and wool, are naturally occurring polymers. The first commercially successful synthetic polymers were made not by polymerization reactions but through the chemical regeneration of the natural polymer cellulose, a condensation polymer of the sugar glucose that is made by plants  

In the viscose rayon process, still used today, cellulose is digested in a concentrated solution of NaOH to convert the —OH groups to —O Na ionic groups. Reac- 

FIGURE 23.4 Filter paper (cellulose) will dissolve in a concentrated ammonia solution containing [Cu(NH3)4] ions. When the solution is extruded into aqueous sulfuric acid, a dark blue thread of rayon (regenerated cellulose) precipitates. 

FIGURE 23.5 Hexamethylenedi-amine is dissolved in water (lower layer), and adipyl chloride, a derivative of adipic acid, is dissolved in hexane (upper layer). At the interface between the layers, nylon forms and is drawn out onto the stirring bar. 

Rayon is a semisynthetic fiber because it is prepared from a natural polymeric starting material. The first truly synthetic polymeric fiber was nylon, developed in the 1930s by the American chemist Wallace Carothers at DuPont Company. He knew of the condensation of an amine with a carboxylic acid to form an amide linkage (see Section 7.6) and noted that, if each molecule had two amine or carboxylic acid functional groups, long-chain polymers could form. The specific starting materials upon which Carothers settled, after numerous attempts, were adipic acid and hexamethylenediamine  

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Apart from paints, electrokinetic separations find limited application for synthetic polymers [905], mainly because of solvent compatibility (CE is mostly an aqueous technique) and competition of SEC (reproducibility). Reasons in favour of the use of CE-like methods for polymer analysis are speed, sample throughput and low solvent consumption. Nevertheless, CE provides some interesting possibilities for polymer separation. Electrokinetic methods have been developed based on differences in ionisation, degree of interaction with solvent constituents, and molecular size and conformation. 

The principal field of application for synthetic polymers as art materials is that of paint binders, which developed in the second half of the twentieth century when manufacturers of artists paints and varnishes realized the potential of synthetic resins used in the decorative household and industrial paint market [81]. The most important families of synthetic artists paints are the acrylics, the vinyl acetate resins, and the alkyds, and Py-GC/MS has been used to identify all these types of modem paints. 

Some important everyday items that are made from polymers with widely different properties Include billiard balls, plastic dishes, soda bottles, barrier and decorative films, egg cartons, polymeric drinking glasses, foam seats, and automotive tires. These applications for synthetic polymers have developed over about 150 years. As shown in Table 2.1, modern polymer material science and technology can be traced back to as early as 1770 [1]. Some Important advances In the understanding of polymer production were developed before World War II. 

For synthetic macromolecules, NMR has been the most powerful method to characterize and to investigate the relationship between the structure and the physical properties. In the field of synthetic macromolecules, NMR is used not only as the routine analytical method but also as the method that has the infinite possibility. In this chapter, NMR applications for synthetic polymers are reviewed. 

MatriCGS for th MALDI Process. The matrix is crucial to the MALDI process. It is generally believed that how the pol5mier is situated in the matrix has a significant influence on the success of the MALDI process. Liquid matrices have been used in a number of applications for biopol5miers but only a few applications for synthetic polymers. Solid matrices are most common for both biopolymers and synthetic polymer work. The earliest experiments (11) that described the MALDI technique employed solid matrices. 

Certain interesting applications for synthetic polymers in the life sciences are unfortunately not treated in this short book. The use of hybrid molecules (bioconjugates) for drug delivery and other purposes is one example, and the use of polymers in bioseparation by aqueous two-phase systems is another. However, the authors nevertheless hope to have given some indication of the importance of polymeric materials for the life sciences and look forward to future results of the continuous research in this area. As an editor, I would like to thank all contributors to this book for their work and their patience with my sometimes sporadic editing efforts. Last but not least, 1 would like to thank Ms. Francoise Wyssbrod, who has read and reread (and sometimes retyped) the chapters making sure that they adhered in every detail to the House Style Manual provided by the publisher. Without her help, this book would not have been possible. 

Electrically conductive polymers are just one of a number of esoteric possible uses for synthetic polymers. These materials are now being considered for a variety of applications. 

This extensive hydrogen bonding bears on several aspects of the chemistry and applications of cellulose. For instance, being a semi-crystalline polymer, cellulose cannot be processed by the techniques most frequently employed for synthetic polymers, namely, injection molding and extrusion from the melt. The reason is that its presumably lies above the temperature of its thermal... 

The range of applications of CE-MS is still rather limited [899]. Few real unknown samples have been analysed by CE-MS. In particular, CE-MS activities for synthetic polymer additive analysis purposes are not abundant. On the other hand, ITP and ITP-CE separations of food additives on a chip have been reported [900]. 

Natural feedstocks must serve many human purposes. Carbohydrates are valuable raw materials due to their actual or potential value. For example, protein plants are already utilizing rapidly reproducing reengineered bacteria that metabolize cellulose wastes converting it to more protein-rich bacteria that are harvested and then used as a protein source feed-meal for animals. Further, natural materials can be used in applications now largely reserved only for synthetic polymers. Sufficient natural materials are available for the supply of both food and polymer needs. 

Physically, there is no difference in the behavior, study, or testing of natural and synthetic polymers. Techniques suitable for application to synthetic polymers are equally applicable to the study and behavior of natural polymers. 

The attentive reader will realize that we have strayed rather far from the hard spheres of the Einstein theory to find applications for it. It should also be appreciated, however, that the molecules we are discussing are proteins that-through disulfide bridges and hydrogen bonding —have fairly rigid structures. Therefore the application of the theory —amended to allow for solvation and ellipticity —is justified. This would not be the case for synthetic polymers, which are best described as random coils and for which a different formalism is employed. This is the topic of Section 4.9. 

As Th-FFF is the technique of choice for synthetic polymers in organic solvents, there are many studies reported in the literature. Th-FFF has been found applicable to virtually every type of lipophilic polymer in the range M=104-107 g/mol using AT-10-100 K,but only to a very limited amount of hydrophilic polymers where Fl-FFF has its traditional strengths. Exceptions include polyfvinyl pyrro-lidone) and polyfethylene glycol) [222]. 

Geotextiles have become one of the most important fields of application for synthetic polymeric fibers. In view of their great importance, we describe them in a separate section. Textiles made of synthetic polymer fibers are used in various applications to address a variety of solids-related problems in civil engineering such as soil support, stabilization, separation and filtration, reinforcement of... 

Polyhydroxyalkanoic acids (PHAs) have been extensively researched since the 1970s because of the potential applications of these compounds as biodegradable substitutes for synthetic polymers. The most successful PHA products are the polyhydroxybutyrates (PHBs). The bacterium... 

Such applications have been commonly related to the analysis of certain gases such as CO2, CO, CH4, NH3, etc, where the MS analysis is less successful. Py-GC/FTIR has been applied In several studies of plant materials [92] and in analysis of peat [93]. Py-GC/FTIR was utilized, for example, for the analysis of humic substances and their metal derivatives [94], starch derivatives [94a], and for synthetic polymer analyses [38aj. 

More recently, in the 1980s and 1990s new series of fused phenothiazine derivatives, the benzo[a,b or c]phenothiazines (BPHTs), were synthesized [3, 21 and references therein] and have received a great deal of attention, mainly because of their potential applications and their important biomedical properties [12-24]. Indeed, some BPHTs are coloured compounds and have been applied as polycyclic dyes or pigments for synthetic polymers, and also in optical recording media ([21] and references therein). Moreover, certain benzo [a or c]phenothiazine derivatives are potential anti-helmintics, possess an antiviral activity, for example inhibiting the multiplication of encephalomyocarditis viruses in tissue cultures ([21,22], and refer-... 

It is well known that nmr is a powerful means for the study of the dynamics of polymer chains both in solution and in the solid state. The relaxation of 13C nuclei has been extensively employed for this purpose in this and other laboratories. I illustrate here a dilferent and particularly intriguing approach which as yet has seen only very limited application to synthetic polymers. This is deuterium quadrupolar echo spectroscopy, as employed in our laboratory by Dr. Lynn Jelinski and her collaborators (20). The presence of the nuclear electric quadrupole lifts the degeneracy of the two deuterium Zeeman transitions, and in the solid state produces a very broad (ca 200 kHz) powder pattern of transitions which can be interpreted to yield very specific motional information for those carbons labelled with deuterium. In Figure 7 are shown spectra of poly (butylene terephthalate) deuterated on the central carbons of the aliphatic chains ... 

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