A new bifunctional polymer-supported extractant for use in metal ion recovery has been synthesized incorporating primary phosphinic acid/secondary phosphine oxide, as well as primary and secondary phosphinic acid ligands, depending on the method of synthesis. Emphasis is on polystyrene in bead form as the polymer support at various divinylbenzene cross-link levels and either with or without macroporosity. Functionalization is with PC13 and various levels of A1C13 as catalyst at temperatures ranging from -78 to +73 °C. From a study of the resin properties as a function of the synthetic variables, we make the following mechanistic conclusions: (1) under mild conditions (<0 °C), 20% substitution to primary phosphinic acid groups occurs; (2) with increasing temperature (23 °C), the extent of reaction increases to 50% with a combination of primary acid and triarylphosphine oxide groups which arise from Friedel-Crafts secondary cross-linking;(3) under forcing conditions (73 °C, high A1C13 level), 100% substitution occurs with dichlorophosphine groups followed by a disproportionation reaction giving rise to primary acid and secondary oxide groups; (4) secondary phosphine oxide groups can be further hydrolyzed to secondary phosphinic acid with strong base. Macroporosity has an influence at higher cross-link levels on both extent of functionalization and reagent accessibility: complete functionalization and reagent accessibility is maintained only with macroporous resins when more than 8% divinylbenzene is utilized for cross-linking.

Softening of thermoplastic polyurethanes (TPU) in a simulated body environment (37°C n-saline) was studied as a function of composition, structure and resultant morphology of these ( AB) n type block copolymers. The structural variations were attempted by changing chemical composition and molecular weight of both hard A and soft B segments and their weight ratio in the polymer. In addition, the influence of bulk and/or surface modifiers, such as "reacted-in" polysiloxanes and fluorinated polyalkylether glycols, was also investigated. The degree of softening, expressed as a percentage decrease of the elastic modulus (5% tensile modulus) upon two hours exposure to the testing environment, is significant, reversible and depends on the ratio of hard to soft segment and the extent of microphase separation. Since these parameters can be selected during the polymer synthesis and processing into desirable shapes, the degree of softening can thus be controlled. This softening at body temperature represents one of the most notable performance advantages of these biomaterials.

In this equation and in all other representations of secondary sites, adjacent units are used only for convenience in drawing; indeed, a large number of the secondary sites must involve interchain cross-linking as the linear polystyrene experiments show (Table V).

The synthesis of an interpenetrating polymer network (IPN) comprised of aliphatic polymers with metal ion complexing ligands within an inert support network is presented. Conditions are defined that permit a maximum entanglement for minimum loss of the polymer from its support network upon continuous elution conditions. The synthesis of the polymerizable metal ion extractant diundecenyl phosphate (DUP) is detailed as well as its incorporation as a toluene solution at a given concentration into macroporous polystyrene beads. The performance of the system after polymerization to give the IPN is compared to that of an unpolymerized control wherein the DUP/toluene solution is simply absorbed into the network (polymer-absorbed extractant, PAE) and to the analogous polymer-trapped extractant (PTE) in which the styrene is polymerized around the extractant. With 50% aqueous ethanol as the eluting solvent, 0.5 M DUP was determined to be the critical entanglement concentration, i.e., the minimum concentration of polymerizable extractant that permits a degree of polymerization high enough so that disentanglement from the support is noticeably hindered relative to the unpolymerized PAE control. Under conditions where the IPN loses 30 % of its extractant, the PAE loses 60% and the comparable PTE loses 71%. Evidence is presented that the key variable in determining monomeric extractant loss is the porosity of the support network, with porosities over 60 vol % losing more than 90% of their extractant. The PTE syntheses show that the extractant acts like a diluent during the formation of the polystyrene chains, leading to high degrees of porosity and, hence, large extractant loss rates. While the DUP/IPN and DUP/PAE absorb fewer mercury ions from aqueous solutions than a DUP/toluene solution, probably due to a loss in extractant ligand mobility within a polymer network, both still perform as well as the PAE made from the conventional liquid extractant bis(2-ethylhexyl) phosphate. Extension of this research into membrane supports is proposed.