Properties of polyamic acid ionomers

Abstract

SYNOPSISPolymers containing amic acid units were produced by reacting an oligomer based on polytetramethylene oxide (PTMO) with 1,2,4,5-benzenetetracarboxylic dianhydride (BTDA) .Neutralization by a metal salt produced amic acid ionomers. Similar to other ionomer systems, neutralization from the acid to the ionomer led to the formation of a separate ionic phase as determined by dynamic mechanical analysis. Phase separation resulted in a substantial increase in mechanical properties. The effect of neutralization level, cation, soft-segment molecular weight, and soft-segment end group on mechanical and thermal properties was investigated. 0 1993 John Wiley & Sons, Inc.

Single nucleotide polymorphism in fibroblast growth factor receptor 4 at codon 388 is associated with prognosis in high‐grade soft tissue sarcoma

“…The results of elemental analysis were in good agreement with the calculated ones (Table I). The ionic chlorine content of the polymers shows that the polycations have a small concentration of ammonium quaternary groups (PUC–T‐1: 29.56 mequiv./100 g polymer; PUC–T‐2: 30.11 mequiv./100 g polymer), specifically to the ionomeric field 23. This provides an interesting system to study the formation of aqueous dispersions with film‐forming ability, which makes them suitable as special adhesive and coating materials 24.…”

Hydrophobic and hydrophilic aggregation of tailor-made urethane acrylate anionomers in various solvents and their network structures

“…Even though the UAA networks were prepared with the same UAA chains, these networks, prepared in different solvents, had very different tensile properties. In general, the mechanical property of ionomers mainly depends on the ionic content per chain, the molecular weight of the chain, the type and nature of the ions, and the property of the nonpolar main chain 36–43. In this work, however, all of the UAA networks were prepared with the same precursor chain with the same ionic content per chain and molecular weight, so these different tensile properties for the UAA networks can be explained in terms of the differences in the network structures formed in the various solvents.…”

“…In general, the ionic aggregation in ionomers is enhanced with an increase of the hydrophobicity of the matrix polymer and solvent used in casting and synthesis 10–18. Also, it is well established that the aggregation of ionic groups into microdomains acting as physical crosslinks gives rise to an increase of the mechanical property of ionomers 37, 38, 40. Therefore, ionic groups of UAA chains are aggregated with one another by the presence of toluene during the crosslinking reaction because of the nonpolarity of toluene; as a result, UATG networks have a greater modulus than UASG networks even though UATG networks have a greater elongation than UASG networks.…”

Preparation of PMDA/ODA polyimide membrane for use as substrate in a thermally stable composite reverse osmosis membrane

“…These divalent cations may act as cross-linkers so that these ionomers behave as thermoplastic elastomers [22]. Immersion of PAA films or fibers into aqueous solutions of transition metal salts leads to chelation of a certain amount of metals onto the PAA, confirming the strong interaction between the PAA and the metal ions [23].…”