Synthetic hydrophilic polymers

RJ Meyer, L Cohen. Rheology of natural and synthetic hydrophilic polymer solutions and related to suspending ability. J Soc Cosmet Chem 10 1-11, 1959. 

These synthetic hydrophilic polymers hydrophobically modified can be good systems with which to try to establish relationships between chemical structure and interfacial characteristics. It was determined the surface pressure - area (tt - A) isotherms at the air - water interface for poly(4-vinylpyridine) quaternized as a function of the methylene group number of the alkyl lateral chains (n). The film formation of these polymers on aqueous subphase at constant pH and ionic strength... 

The structures of a number of synthetic hydrophilic polymers as a representative range of those commonly used are shown in Fig. 1. Many common hydrophilic polymers are based on methacrylate or acrylate backbones. One of the most common is polyacrylic acid, which forms the basis of many hydrogel materials (Fig. lA). Although simple polyacrylic acid is water soluble, it can be easily cross-linked to form an insoluble network polymer that still, however, retains high affinity for water and is capable of adsorbing large amounts of water to form hydrogels these are discussed later. Polymethacrylic acid-based polymers are similar in nature (Fig. IB). One of the most commonly used polymers for contact lenses, polyhydroxyethyl methacrylate, is based on a similar backbone (Fig. 1C). 

Fig. 1 Structures of some common synthetic hydrophilic polymers (A) poly aery lie acid, (B) polymethacrylic acid, (C) polyhydroxyethyl methacrylate, (D) polyvinyl alcohol, (E) polyvinyl acetate, (F) PEG/PEO, (G) polyacrylamide, (H) polyvinylpyrrolidinone, (I) Nylon 6, and (J) a simple polyurethane.

Many types of superabsorbents have been prepared from various materials, by various methods, and in different shapes. They are modified natural hydrophilic polymers such as starch, cellulose, alginic acids, etc. and synthetic hydrophilic polymers such as poly (acrylic acid) and poly(sodium acrylate). Most of them have anionic moieties such as poly(sodium acrylate) and poly(vinyl sulfonate). Now, many types of superabsorbents having not only anionic groups but also cationic groups such as ammonium groups, phospho-nium groups, or betaine have been prepared from both... 

Consequently, synthetic hydrophilic polymers such as polyvinyl alcohol, and polyvinylpyrrolidone, and polyvinylmethyl ester are interesting for two reasons i.e. (1) they coordinate with metal ions thereby decreasing the rate of metal reduction, and (2) they prevent aggregation of colloidal particles. The simplicity of preparation of colloidal metal dispersions, the feasibility of controlling particle sizes, and some other advantages place these polymers as promising catalytic systems [32,53, S3 a]. 

Supports based on synthetic hydrophilic polymers such as polyvinyl alcohol and polyacrylamide or natural polymers like agarose have been developed. 

A variety of synthetic hydrophilic polymers were tested as drug carriers, among them poly(ethylene glycoljs (PEG) playing probably the most important role. 

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