Specialty Polymer Applications

Comparatively little attention has been directed to other specialty polymer uses for condensed tannins over the past 10 years, possibly due to the strong focus on their application as wood adhesives (88, 186). This seems unfortunate because condensed tannins offer excellent opportunities for use as specialty polymers due to the high degree of nucleophilicity of the phloroglucinol or resorcinol A-rings, the excellent potential for complexation to the catechol or pyrogallol B-rings and, in the procyanidins or prodelphinidins, the comparative ease with which the in-terflavanoid bond can be cleaved to permit the formation of derivatives substituted at the C-4 carbon. 

Taking advantage of the many aromatic hydroxyl functions in conifer bark tannins, Hartmann (83) used ground bark as a polyol for reaction with isocyanates to prepare urethane foams with particularly good flammability resistance. Most uses for conifer bark tannins that involve reactions with the hydroxyl functions center on their complexation with cations. When sulfonated, condensed tannins can also be used as water-soluble heavy metal complexes. One of the more interesting of these applications is the development of water-soluble heavy-metal micronutrient complexes that have been used to correct iron deficiency in citrus 

Condensed tannins are excellent clay dispersants. Sulfite extracts from conifer tree barks are very effective in reducing the viscosity and increasing the gel strength of muds used in well drilling (72, 92, 145, 246, 248). Condensed tannins still face strong competition from lignosulphonates for this application, particularly because of the comparatively low thermal stability and salt tolerance of the tannin (96). However, reaction of tannins with chromium increases their thermal stability considerably to permit their use in muds for wells drilled as deep as 6000 feet (208). Sulfonated condensed tannin derivatives have found use as dispersants in other specialty applications, such as ceramic clays, pigments, carbon black, and pesticides (93, 96). 

Acknowledgements. RWH is indebted to Ginger Rutherford who assisted in gathering reference materials, Julia Wilson, Nancy Greene, and Sue Moore who typed a number of drafts, and Drs. L. Y. Foo, G. W. McGraw, J. J. Karchesy, and P. E. Laks who made helpful suggestions. 

1 Allan G G 1969 Reaction products of lignin and bark extracts and process for same. U S Pat No 3470148 

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Applications of Polymers. Uol 7, Specialty Polymers and Polymer Processing, Pergamon Press, New York, 1989. 

Ruthenium-NHC complexes exhibit activity in a very wide field of applications. Due to their unique ability to break and reassemble olefin bonds under reaction conditions very favourable to design simple processes, applications in nearly any chemical discipline can be foreseen. This field may span from manufacturing of specialty polymers and rabbers to pharmaceuticals, pharmaceutical intermediates, agrochemicals, fragrances, dyes, specialty chemicals for electronic applications or fine chemicals from natural feedstock and many more. Below are described Ru-NHC catalysed reactions applied from pilot to full commercial scale. 

Suzuki cross-coupling has found applications in the preparation of specialty polymers, too. Rigid rod polymers may have very useful properties (the well-known Kevlar, poly(p-phenyleneterephtalamide) belongs to this family, too) but they are typically difficult to synthetize, characterize and process. Such materials with good solubility in organic solvents [38] or in water [39] were obtained in the reactions of bifunctional starting compounds under conventional Suzuki conditions with [Pd(PPh3)4] and [Pd(TPPMS)3] catalysts, respectively (Scheme 6.15). 

Examples of applications in eight areas, ranging from adhesives to specialty polymers, are listed in Table 11.11. 

Significant developments have occurred in recent years in the fields of biopolymers and biomaterials. New synthetic materials have been synthesized and tested for a variety of biomedical and related applications from linings for artifical hearts to artifical pancreas devices and from intraocular lenses to drug delivery systems. Of particular interest in the future is the development of intelligent polymers or materials with special functional groups that can be used either for specialty medical applications or as templates or scaffolds for tissue regeneration. 

The other isomer, 1,2-butadiene, a small by-product in 1,3-butadiene production, has no significant current commercial interests. However, there are a number of publications and patents on its recovery and applications, particularly in the specialty polymer area (8,9) and as a gel inhibitor (10). 

A large number of compounds related to styrene have been reported in the literature, Those having the vinyl group CH2=CH—attached to the aromatic ring are referred to as styienic monomers, Several of them have been used for manufacturing small-volume specialty polymers. The specialty styreme monomers that arc manufactured in commercial quantities arc vinyl toluene, /r, -methylstyrene, or-methylstyrene. and divinylbenzene. In addition, 4-fert-butylstyrene (TBS) is a specialty monomer that is superior to vinyltoluene and pnra-methylstyrene in many applications. Other styrenic monomers produced in small quantities include chlorostyrene and vinylbenzene chloride. With the exception of a-methylstyrene, which is a by-product of the phenol-acetone process, these specialty monomers are more difficult and expensive to manufacture than styrene... 

Super absorbent polymers. These cross-linked acrylic polymers are used in baby diapers. Copolymer versions are used in agriculture and other specialty absorbent applications. 

Fermentation-derived organic acids and their esters are potentially important chemical feedstocks for polymers and specialty polymers, but most significantly as alternative solvents for industrial and consumer applications. For example, lactate esters are derived from renewable carbohydrate raw materials such as cornstarch. They exhibit much lower toxicity compared with halogenated hydrocarbons and ethylene glycol ethers and are environmentally benign. Some studies suggested that lactate ester solvents have the potential of replacing petroleum-based solvents... 

The most common polymers used in FR wire and cable applications are PVC, polyolefins, fluoropolymers, and silicone polymers. Thermoplastic polyurethanes (TPUs) and other specialty polymers such as chlorosulfonated polyethylene also serve niche applications in wire and cable. The approaches to achieve flame retardancy in each of these polymer systems along with issues unique to wire and cable application are discussed in the following sections. 

Classification by End Use Chemical reactors are typically used for the synthesis of chemical intermediates for a variety of specialty (e.g., agricultural, pharmaceutical) or commodity (e.g., raw materials for polymers) applications. Polymerization reactors convert raw materials to polymers having a specific molecular weight and functionality. The difference between polymerization and chemical reactors is artificially based on the size of the molecule produced. Bioreactors utilize (often genetically manipulated) organisms to catalyze biotransformations either aerobically (in the presence of air) or anaerobically (without air present). Electrochemical reactors use electricity to drive desired reactions. Examples include synthesis of Na metal from NaCl and Al from bauxite ore. A variety of reactor types are employed for specialty materials synthesis applications (e.g., electronic, defense, and other). 

Louis Hegedus Coming from the specialty chemicals applications, I would like to further emphasize what Sheldon Isakoff said. Take polyethylene, which our company uses extensively for a variety of applications. What do we do with it We fill it, modify it, functionalize it, formulate it, compound it, extrude it, laminate it, and end up with such vastly different products as battery separators, membranes, construction materials, insulation materials, battery electrodes, and microfilters. It is amazing what you can do with any given polymer. Much research emphasis today is on the properties of bulk polymers themselves. There is a whole science associated with com-... 

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