Poly diblock ionomer

The physical properties of the acid- and ion-containing polymers are quite interesting. The storage moduli vs. temperature behavior (Figure 8) was determined by dynamic mechanical thermal analysis (DMTA) for the PS-PIBMA diblock precursor, the polystyrene diblock ionomer and the poly(styrene)-b-poly(isobutyl methacrylate-co-methacrylic acid) diblock. The last two samples were obtained by the KC>2 hydrolysis approach. It is important to note that these three curves are offset for clarity, i.e. the modulus of the precursor is not necessarily higher than the ionomer. In particular, one should note the same Tg of the polystyrene block before and after ionomer formation, and the extension of the rubbery plateau past 200°C. In contrast, flow occurred in... 

The novel reaction scheme which we had proposed for "blocky" ionomers through emulsion polymerization prompted us to prepare very well defined ion containing block copolymers through anionic polymerization. The initial system chosen for synthesis, modification, and characterization was the poly-styrene-poly(isobutyl methacrylate) diblock (PS-PIBM DB) copolymer. This particular system was chosen for the following reasons ... 

Figure 4. FT-IR spectra of (A) polystyrene/poly(isobutyl methacrylate) diblock copolymer and (B) carboxylated block ionomer obtained after hydrolysis with K0-.

Another example is a recent study of confinement effects in ionomers carried out at W-band. Electronic Tx and T2 relaxation as a function of temperature was measured at W-band for spin probes localized at the interface between the ionic clusters and the polymer. Excellent angular selection W-band EPR which resolves x-, y-, and z-orientations of the nitroxides in the magnetic field allowed authors to probe electronic relaxation along those orientations while the sample remained macroscopically disordered. Based on these measurements of the electronic relaxation as a function of the nitroxide orientation, it was concluded that reorientation of these spin probes has clear uniaxial features. Moreover, evidence was presented that the dynamic constraints on the poly(isoprene) chains in the diblock copolymer propagate over the whole chain consisting of approximately 170 monomer units. 

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