Ionomeric Blends

Table 5.52 PO/PPE/st3a-ene copolymer blends ionomeric cross-linking mediated by metal cations ...

An interesting method to improve the S-PEEK performances is to prepare physically cross-linked membranes by blending ionomeric polymers with different mechanical properties. The blending technique makes the advantage of combining the positive features of each component with a very simple procedure. Better electrochemical characteristics are... 

Blends of ionomeric Zn-maleated EPDM mbber (Zn-mEPDM) and Zn-maleated PP (Zn-mPP) show behaviors typical of TPEs [74]. The composition ranges of 90-10 (Zn-mEPDM-Zn-mPP, wt%)... 

Different types of interaction in rubbery materials, which include PE, plasticised PVC, TPE, ionomeric polyblends, and blends of plastics and rubbers can be characterised by different types of IR spectroscopic techniques. 

EPDM, sulphonated Ionomeric elastomer Uniroyal PP/Acrylic rubber blends... 

Examples of some immiscible polyolefin blends that have been compatibilized through ionomeric crosslinking between ionomeric groups on each polyolefin are listed in Table 5.53. 

Compatibilized blends of 77 parts EPDM-SOjZn salt and 9 parts S-co-4-vinylpyridine with 4 parts ZnSt plasticizer were prepared in an internal mixer at 200°C [Lundberg et al., 1988 Agarwal et al., 1987 Peiffer et al, 1986]. The blends were characterized by FTIR, DMA, melt viscosity, DSC, and SEM. Mechanical properties were compared to blends containing unfunctionalized PS or containing EPDM-SOjNa or Mg salts. A copolymer linked by ionomeric crosslinks may form associations between sulfonate anion and pyridine nitrogen mediated by Zn cation. 

Carboxylated nitrile rubber Zn ionomer (90-50)/EAA Zn ionomer (10-50) Physical properties vs. blends of non-ionomeric polymers/FTIR/DMA/also use of recycle Antony et al. 2000... 

Some unusual ester cross-linking reactions have been proposed as copolymerforming processes for immiscible PO blends (Table 5.48). Alternative mechanisms include consideration of the possible contributions of simpler processes such as IPN formation, radical-radical coupling, or ionomeric cross-linking. 

Coran and Patel (1983b) have shown that the mechanical properties of dynamically vulcanized NBR-PP blends can be improved through copolymer formation between the two immiscible polymers concurrent with vulcanization. In the first example in Table 5.53, block copolymer resulted from reaction of amine-terminated NBR with anhydride-terminated PP. The latter was prepared through functionalization of PP with MA in the presence of radical initiator. In the second example, a block copolymer may have resulted from reaction of acid-terminated NBR with a primary amine-terminated PP. The latter was prepared in a prior reaction between maleic anhydride-terminated PP and triethylenetetramine. It is also possible that the block copolymer may be linked through ionomeric association resulting from protonation of PP-amine with NBR acid. 

In dynamic mechanical analysis (DMA), Tg is determined from loss modulus [438]. The results show that the blends are at least partially compatible because all blends exhibit a single Tg, which corresponds to both ionomeric forms although they shift as a function of blend composition [430]. Linares and coworkers proposed the following explanation for the discrepancies between DSC and DMA data [430]. These blends. 

From a topological point of view, the IPN s are closely related to polymer blends, block and graft copolymers, AB-crosslinked copolymers " and ionomeric blends. Some interesting hybrids exist between the IPN s and other polymer materials. The thermoplastic IPN s contain physical crosslinks rather than chemical (covalent) crosslinks. Physical crosslinks can be formed from block copolymers, ionomers or semi-crystalline polymers. When the temperature is raised above the softening point of the respective components, the material flows like a thermoplastic. At service temperatures, it behaves like an IPN, with thermoset behavior. Table 1 summarizes some of the terminology used to describe IPN structure and morphology. 

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