A study of structure and dynamics of poly(aspartic acid) sodium/poly(vinyl alcohol) blends by 13 C CP/MAS NMR

Poly-α,β-DL-aspartyl-L-cysteine: a novel nanomaterial having a porous structure, special complexation capability for Pb(II), and selectivity of removing Pb(II)

Poly-α,β-DL-aspartic acid is known as a green chelant of various metal ions. To provide a novel nanochelant for treating Pb(II) poisoning, poly-α,β-DL-aspartic acid was modified with L-Cys to form poly-α,β-DL-aspartyl-L-cysteine (PDC; MW, 27273). DL-Asp was converted into polysuccinimide through a thermal polycondensation, and the amidation of polysuccinimide with L-Cys provided PDC. In water, PDC formed various porous nanospecies. In the mouse lead intoxication model, both intraperitoneal and oral administration of PDC (0.1, 1.0, and 10.0 nmol/kg) dose dependently removed Pb(II) accumulated in the organ, bone, and blood. PDC did not remove the essential metals including Cu(2+), Fe(2+), Mn(2+), Zn(2+), and Ca(2+) of the treated mice. The porous feature and size of the pH- and concentration-dependent nanospecies of PDC benefited the removal of Pb(II).

Study of a binary interpenetrated polymeric complex by correlation of rheological parameters with zeta potential and conductivity

The interpenetrated macromolecular chains complexation between poly(aspartic acid) and poly(vinyl alcohol) in aqueous solution it was investigated. The interpolymer complexation process was evaluated through dynamic rheology. The aspects concerning the stability of the tested homopolymers and the prepared interpolymeric complex there were achieved from the evaluation of the aqueous solutions'zeta potential and also by determining the pH influence upon the zeta potential and the conductivity. The data obtained through the rheological dynamic measurements were correlated with the composition of the polymeric mixture, the dependence of zeta potential and conductivity. The study reveals the conditions for the formation of interpenetrated polymeric complex as being a ratio of 70wt.% PAS to 30wt.% PVA at 22 degrees C and 50/50 PAS/PVA ratio at 37 degrees C temperature. From the pH influence upon the zeta potential values it was evidenced the PAS aqueous solution does not reach the isoelectric point. At the same time, PVA solution and the complex PAS/PVA reaches the isoelectric point at strongly acid pH. The better stability of PAS, PVA and their mixture in solution is recorded in the alkaline domain (7.5<or=pH>or=12). The conductivity increases with the rising of the PAS content, pH and temperature. Other characteristics of the prepared interpenetrated polymeric structure, as for example thermal stability, there are also presented.