Semirigid polymer gels

Semirigid Polymer Gels for Size Exclusion Chromatography... 

A wide variety of commercial semirigid polymer gels exist for both organic and aqueous SEC. Following the introduction of smaller particle size packings. 

Belenkii et al. reported in 1975 (8) the SEC of PVP with unspecified molecular weight using Pharmacia Sephadex G-75 and G-lOO columns and a 0.3% sodium chloride solution as the mobile phase. Deviations from universal calibration behavior were noticed from PVP, dextran, polyethylene oxide (PEG), and polyvinyl alcohol. With the development of the important semirigid polymer gel, Toyo Soda TSK-PW columns for water-soluble polymers, Hashimoto et al. reported in 1978 (9) the SEC of PVP K-30 and K-90 using TSK-PW 3000 and two 5000 columns an 0.08 M Tris-HCl buffer (pH =... 

Support materials may be subdivided into two classes both of which are available in 5-10 pm particle size (a) semirigid cross-linked polymer gels, and (b) inorganic materials with controlled pore size, such as microporous silicas. 

Biopolymers by Guenet [3], which have been primarily concerned with thermoreversible gels in flexible polymer systems. The present review will focus on thermoreversible physical gels formed from rigid rod-like and semirigid polymers. 

Cytochrome c dissolved in a film of polyethyleneoxide (PEO) or polyacrylamide (PAA) and immobilized at the surface of carbon electrode in this way yields a well-defined cyclic voltammogram (Fig. 16). The parameters of the electrode process are almost identical to those of the process in an aqueous medium. This finding can be apparently related to a high content of water in the gel. This system can be used in investigations of electron transfer properties of semirigid polymers suitable for constructing biosensors and to study solid-state enzyme catalysis. [221]. 

Aqueous SEC was first reported in 1959 by Porath and Flodin [1]. They separated proteins and salts according to molecular size by using cross-linked dextran gels. Since then it has been widely employed, especially in the field of biochemistry, for various purposes such as purification of proteins and nucleic acids, estimation of molecular masses of proteins and determination of molecular mass distributions of polysaccharides. In addition, it has been a powerful tool for the determination of molecular mass distributions of water-soluble synthetic polymers since high-performance aqueous SEC was realized in 1978 by the development of semirigid microparticulate macroporous supports based on hydrophilic synthetic polymers [2-4]. 

The term sol-gel is used broadly to describe the preparation of ceramic materials by a process that involves the preparation of a sol, the gelation of the sol, and the removal of the liquid. A sol is a suspension of colloidal particles in a liquid or a solution of polymer molecules. The term gel refers to the semirigid mass formed when the colloidal particles are linked to form a network or when the polymer molecules are cross-linked or interlinked. Two different sol-gel processing routes are commonly distinguished the particulate (or colloidal) gel route in which the sol consists of dense colloidal particles (1 to 1000 nm) and the polymeric gel route in which the sol consists of polyma- chains but has no dense particles >1 nm. In many cases, particularly when the particle size approaches the lower limit of the colloidal size range, the distinction between a particulate and a polymeric system may not be very clear. 

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