Ionomer blends, morphological

Thermoplastic elastomers (TPE), 9 565-566, 24 695-720 applications for, 24 709-717 based on block copolymers, 24 697t based on graft copolymers, ionomers, and structures with core-shell morphologies, 24 699 based on hard polymer/elastomer combinations, 24 699t based on silicone rubber blends, 24 700 commercial production of, 24 705-708 economic aspects of, 24 708-709 elastomer phase in, 24 703 glass-transition and crystal melting temperatures of, 24 702t hard phase in, 24 703-704 health and safety factors related to, 24 717-718... 

Landis, F A. and Moore, R. B. 2000. Blends of a perfluorosulfonate ionomer with poly(vinylidene fluoride) Effect of counterion type on phase separation and crystal morphology. Macromolecules 33 6031-6041. 

In summary, I have discussed a semi-phenomenological elastic theory for ion clustering in ionomers. The theory is consistent with observed trends in perfluorinated ionomers. I have also demonstrated the percolatlve nature of ion transport in these ionomers and computed quantitatively their tensile modulus. Finally, I have discussed the Influence of morphology on ion selectivity in perfluorinated ionomer blends. In particular, I have pointed out that an universally preferred morphology beneficial to all blends does not exist the ideal morphology must be individually determined based on component properties. Most of the theories and conclusions here are very general and applicable to other composite polymer systems. 

Figure 15.6. Morphology of typical Polyamide/impact modifier blends — TEM., Phosphotungstic acid stain, top — PA-6/ethylene copolymer/ionomer blend (21,000X) bottom — PA-6/maleated EPR (3 1) blend (30,000X).

Su et al. (8) studied the mechanical properties and morphological structure relationship of blends based on sulfated EPDM ionomer and PP. They synthesized Zn neutralized low degree sulfated EPDM (Zn-SEPDM) ionomer and PP blends and studied their mechanical properties. They found that Zn + neutralized low degree sulfated EPDM ionomer and PP blends have better mechanical properties than those of PP/EPDM blend, as shown in Fig. 14.4. They explained the reason why mechanical properties are higher for Zn-SEPDM and PP than for PP and EPDM using scanning electron microscopy (SEM) (Fig. 14.5). Finer dispersed phase size and the shorter interparticle distances are the main reasons for the improved mechanical properties of the PP/EPDM blend. 

In general, VanOene s experimental studies support the conclusions of his theory. As shown in Figure 9.11, extrusion of blends of an ionomer with polypropylene gave complementary morphologies. When the blend (cursorily mixed) was rich in ionomer (90 10), the polypropylene stratified (phase p unstable in phase a) on the other hand, when polypropylene was the major component (10 90), the ionomer formed droplets [( 2)a > phase a always stable in j ]. It was shown that the morphology was not much affected by shear rate, residence time, or temperature. 

The second part, Chapters 2-9, is concerned with polymer blends, including mechanical blends, graft copolymers, block copolymers, ionomers, and interpenetrating polymer networks. The development of most chapters proceeds from synthesis to morphology, and then shows how morphology affects or controls the physical and mechanical behavior of the finished material. The most exciting development of the past decade, the electron microscope studies of the details of phase separation, is emphasized. 

Compatibihzed blends of 90 parts PBT and 10 parts oxidized PP or its corresponding Na ionomer were prepared in TSE at 240 °C (Dang et al. 2005). Blends were characterized by mechanical properties, morphology, and MFR compared to blends with unfunctionalized PP. 

Willis J M and Favis B D (1988) Processing-morphology relationships of compatibilized polyolefin/ polyamide blends. Part I The effect of an ionomer compatibilizer on blend morphology, Polym Eng 28 1416-1426. 

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