Tailoring the ionic association and microstructure of ionomers with various metal salts

Abstract

In this work, we investigated the effects of metal stearate salts on the structure, morphology, and properties of poly(ethylene-acrylic acid) neutralized by zinc salts (PI). The samples were characterized in detail with spectroscopic [Fourier transform infrared (FTIR) spectroscopy], microscopic (hot-stage optical microscopy), thermal [thermogravimetric analysis, modulated differential scanning calorimetry, and dynamic mechanical analysis], mechanical, and scattering (small-angle neutron scattering and small-angle X-ray scattering) techniques. The melt rheological properties of the samples were also investigated. The structure of the ionic domains was determined by the type of cations and the salt proportion (FTIR). The predominant interaction was found to exist between the metal stearate and the ionic group. Na þ cation exhibited a unique behavior, whereas Zn 2þ showed a coordinated structure and, hence, properties. The ionic groups in the Na and Zn stearate systems existed as multiplets and clusters, but multiplets were the main structure in the Al salt system. The salts acted as plasticizers above their melting points (mp's) but as fillers below their mp's. The melt flow properties of PI were significantly affected by the metal cation and salt proportion and were improved greatly by the introduction of the salts. V C 2012 Wiley Periodicals, Inc. J Appl Polym Sci 126: E130-E141, 2012 Figure 8 Effect of metal stearates on the stress-strain behavior of PI. E140 GAO, CHOUDHURY, AND DUTTA Journal of Applied Polymer Science

Tailoring the Viscoelasticity of HEMA-Functionalized Styrene-Acrylate Copolymers Using Coagulants

“…This ratio is a measure of the strength of ion pairs. Additionally, T g and rubbery modulus for ionomers reportedly increase with increased q / a . , Accordingly, the change in viscoelasticity of the copolymers was due to the functional groups of HEMA and MAA because the cations of metal salts as counterions may form cross-links with these momoners. , …”

“…18,19 Accordingly, the change in viscoelasticity of the copolymers was due to the functional groups of HEMA and MAA because the cations of metal salts as counterions may form cross-links with these momoners. 17,18 3.2. Effects of HEMA Content.…”

“…15,16 Ionic associations can act as physical cross-links and thus significantly increase melt viscosity, rubbery modulus, and glass-transition temperature (T g ). 17 −22 Meanwhile, multiple interactions including cross-linking reactions play a great role in polymer viscoelastic properties. Craig et al 23,24 showed that dynamic viscosity and storage modulus could be regulated by incorporating transient crosslinks with different dissociation rates within the P4VP-based network using various organometallic cross-linkers.…”

“…Thus, regulating polymer viscoelastic properties over a wide temperature range is difficult. Ionomers are polymers containing small amounts of ionic groups in nonionic backbone chains. , Ionic associations can act as physical cross-links and thus significantly increase melt viscosity, rubbery modulus, and glass-transition temperature ( T g ). − …”