Accessibility of Functional Groups

The inherent viscosity is a measure of the polymer molecular weight. Larger values of indicate higher molecular weights. Early precipitation of the polyurethane occurs in 

TABLE 2-4 Effect of Solvent on Molecular Weight in Polymerization of Bis(4-isocyauatophenyl)methane with Ethylene GlycoP  

Polymerization temperature 115°C. c Measured in dimethylformamide at room temperature. 

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Accessibility of functional groups for an immobilization reaction is further... 

Accessibility of functional groups for an immobilization reaction is further influenced by microenvironmental effects. Steric hindrance by neighbouring groups, interaction with neighbouring groups and solvent molecules, or alterations of pKa-values of dissociable groups can lead to a shifted reactivity. 

Thus, the investigation of the porous structure of polymeric sorbents and the determination of dependencies of the porous structure parameters on the synthesis condition (the eunount and the nature of the crosslinking agent, the amoxint and the nature of the porogenic agent and the molecular mass of polystyrene) make it possible to synthesize the porous polymers of certain structure. The established laws of the adsorption of acid gases by modified polymers of different structure make it possible to optimize their porosity at which the maximum accessibility of functional groups for the adsorbed molecules is attained. 

The result of this set of experiments may be used as an indication as to what to expect when solid surfaces are tried. The coupling efficiency will obviously be a function of the accessibility of functional groups—both carboxyl on the polymer and nucleophile on the collagen. 

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