Highly resistant polymers classes

Some examples of classes of highly resistant polymers are presented in Table 16.1 (Critchley et al., 1983). 

Carboxyhc acids react with aryl isocyanates, at elevated temperatures to yield anhydrides. The anhydrides subsequently evolve carbon dioxide to yield amines at elevated temperatures (70—72). The aromatic amines are further converted into amides by reaction with excess anhydride. Ortho diacids, such as phthahc acid [88-99-3J, react with aryl isocyanates to yield the corresponding A/-aryl phthalimides (73). Reactions with carboxyhc acids are irreversible and commercially used to prepare polyamides and polyimides, two classes of high performance polymers for high temperature appHcations where chemical resistance is important. Base catalysis is recommended to reduce the formation of substituted urea by-products (74). 

The polyimides are the best developed class of high temperature polymers with exceptional oxidation resistance. They are generally based on the condensation polymerization of aromatic dianhydrides with diamines forming a soluble polyamic acid, followed by intermolecular cyclodehydration to the insoluble polydiimide. Their maximum use temperature is 358 °C. Recently H. Reimschuessel prepared a polyimide... 

Recently, new classes of synthetic and natural polymers such as zwitterionic polymers [215-221], peptoids [222], carbohydrate and glycerol derivatives [223-225], and poly-L-lysine-graft-dextran [226] have anerged as candidate materials for the development of non-PEG protein-resistant surfaces. For example, Jiang and coworkers danonstrated that zwitterionic materials such as poly(sulfobetaine methacrylate) were not only highly resistant to nonspecific protein adsorption [227-230] but also able to significantly decrease bacterial adhesion and biofilm formation [231]. 

Hasegawa, M. etal. (1995) A new class of high strength, water and heat resistant polymer-cement composite solidified by an essentially anhydrous phenol resin precursor. Cement and Concrete Research 25,1191-1198. 

Another interesting polymer type is the class of polyvinyl saccharides. These polymers display a high resistance to microbial attack because of an all carbon backbone. In addition, they exhibit a stable solution structure in the presence of salts.(32,33) Yet their viscosification efficiency could still be improved. ... 

Aromatic polyimides are an important class of high-performance polymers with interesting properties such as good chemical and solvent resistance, high thermal and mechanical properties, and high optical transparency. These excellent properties make them suitable for engineering plastics to be used in... 

Besides these excellent characteristics, one major limitation associated with common classes of epoxy resins is their poor durability in exterior conditions. Nevertheless, epoxy resins have been the workhorse of high performance polymers for protective coatings where high corrosion and chemical resistance are important. 

Brominated copolymer of isobutylene and para-methylstyrene (DIMS) is the latest new class of synthetic rubber that has been developed for the rubber industry. The sole producer of this new class of elastomer is ExxonMobil, which commercialized it successfully under the trade name Exxpro in the first decade of this new century. The advantage of this new polymer class vs. bromobutyl rubber is that this new elastomer possesses a completely saturated backbone and possesses more reactive benzylic bromine functionality than the bromine sites on the conventional bromobutyl backbone. This means that DIMS reportedly gives superior performance in service vs. BUR. This superiority is shown as better high-temperature resistance, better aging stability than either BUR or EPDM, better weathering resistance, and better ozone resistance. Also, BIMS provides the potential of imparting superior air permeability resistance. 

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