Dynamic Melt Rheological Properties of Ionomers Based on Poly(Ethylene-<i>co</i>-Acrylic Acid) and Poly(Ethylene-<i>co</i>-Methacrylic Acid)

Kurian, Thomas; Nishio, Mihoko; Nishioka, Akihiro; Takahashi, Tatsuhiro; Koyama, Kiyohito

doi:10.1080/00914030600754842

Cited by 7 publications

(1 citation statement)

References 19 publications

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“…The slopes in the Arrhenius plots of the shift factor ( a T ) shown in the inset of Figure a correspond to the flow activation energy, E a , whose values are tabulated in Table . This increase in activation energy due to the ion group’s incorporation has been reported in other ionomers − and can be simply interpreted as a restriction to the flow caused by the ion clusters.…”

Section: Results and Discussionsupporting

confidence: 68%

One-Pot Synthesis of High-Melt-Strength Isotactic Polypropylene Ionomers

et al. 2021

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High melt strength (HMS), shear thinning, and extensional strain hardening (SH) are highly desirable properties in commercial polypropylene, which are typically achieved by the incorporation of long-chain branching (LCB). The current state-of-the-art approach to produce LCB involves post-reactor modification steps, which are not only costly but also generate undesirable side products as a result of polymer chain scission. We report a novel one-pot synthetic route to produce HMS isotactic polypropylene (iPP) ionomers bearing aluminum carboxylate groups. The synthesis of iPP ionomers is achieved by the direct copolymerization of an alkenyl aluminum comonomer and is facilitated by a novel C 1 -symmetric metallocene catalyst, producing highly isospecific iPP ionomers (T m > 157 °C) with high activity (>200 000 g-polymer mmol-Zr −1 h −1 ). X-ray scattering experiments conducted in the solid and melt states confirm the presence of ion clusters as independent entities from the crystalline lamellae. The ion content in the iPP ionomers is very low (<0.1 mol %), which results in insignificant effects on the crystallinity, melting point, and mechanical properties when compared to the iPP homopolymer. Remarkably, such a low level of ion content is sufficient to drastically improve the processability of the ionomers, as indicated by the increase in melt strength, shear thinning, and extensional SH.

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Section: Results and Discussionsupporting

confidence: 68%

One-Pot Synthesis of High-Melt-Strength Isotactic Polypropylene Ionomers

et al. 2021

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Contraction flow of ionomers and their corresponding copolymers: Ionic and hydrogen bonding effects

2019

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The contraction flow of several commercial ionomer melts and their corresponding copolymers was studied numerically using a viscoelastic integral constitutive model developed by Kaye and Bernstein, Kearsley, and Zapas, known as the K-BKZ model. First a detailed rheological characterization was performed to calculate the parameters of the K-BKZ model used in the flow simulations. The effects of ionic and hydrogen bonding associations have been studied on the entry pressure drop, on the corner vortex in the capillary contraction, as well as on the vortex strength. In all cases, the ionomers exhibit much more significant effects compared to their copolymers, the more so as the number of ionic associations present in their backbone increases. This is due to strong ionic associations present in the ionomers that give rise to strong strain hardening effects important in entry flows. Compared to ionic associations, the effects of hydrogen bonds are insignificant particularly at levels less than 5 mol. %.

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Rheology of sodium and zinc ionomers: Effects of neutralization and valency

et al. 2020

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Using a parallel-plate rheometer equipped with a partitioned plate and the Sentmanat extensional rheometer fixture, a full rheological characterization of several commercial ionomers (sodium and zinc) and their corresponding parent copolymers has been carried out. Particular emphasis has been placed on the distribution of the relaxation times to identify the characteristic times, such as reptation, Rouse, and lifetime of associations that are associated with entanglements, ionic and hydrogen bonding associations. As such, scaling laws have been used to calculate the order of magnitude of these characteristic times that are important parameters to gain a better understanding of their rheological behavior. To study the effects of ionic reversible associations, the commercial ionomers were completely un-neutralized and their rheological behavior was compared directly with their associative counterparts. The rheological comparison included the linear viscoelastic moduli, the damping function, and extensional rheology, demonstrating the significant effects of ionic interactions. Moreover, the rheological properties of sodium and zinc ionomers are also compared addressing the effect of valency of ions (Na+ vs Zn++).

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Dynamic Melt Rheological Properties of Ionomers Based on Poly(Ethylene-co-Acrylic Acid) and Poly(Ethylene-co-Methacrylic Acid)

Cited by 7 publications

References 19 publications

One-Pot Synthesis of High-Melt-Strength Isotactic Polypropylene Ionomers

One-Pot Synthesis of High-Melt-Strength Isotactic Polypropylene Ionomers

Contraction flow of ionomers and their corresponding copolymers: Ionic and hydrogen bonding effects

Rheology of sodium and zinc ionomers: Effects of neutralization and valency

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