ISSN:
1435-1536
Keywords:
Key words Periodic copolymer
;
ionomer
;
alkali-soluble poly-electrolyte
;
poly(ethylene-per-ethylene-per-acrylic acid)
;
conformational transition
;
hydrophobically modified polyelectrolyte
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract A sequence-ordered, periodic copolymer of ethylene, ethylene, and acrylic acid, poly (ethylene-per-ethylene-per-acrylic acid) (PEEA), with M w=1.44×105 has been synthesized by alternating copolymerization of 1,3-butadiene and methyl acrylate, followed by hydrogenation and hydrolysis. Aqueous solution and dissociation properties of the alkali-soluble PEEA were explored by potentiometric titration and intrinsic viscosity at 25 °C. The pH values of PEEA were almost constant (pH = 6.48 ∼ 6.55) with an increasing degree of dissociation (α) from 0.3 to 0.8 at C s=50 mN NaCl. Correspondingly, the plots of negative logarithm of apparent dissociation constant (pK a) against α showed a reversed S-shape curve over the whole α, indicating an extensive precipitation and subsequent tran-sition from compact to coiled conformation. The intrinsic viscosity steeply increased with α above 0.4 up to 9.97 dl/g at α = 1.0. Good agreement between the observed electrostatic potential and that calculated from the rod model with a smeared charge density was observed in the region of α higher than 0.9. The dissociation and dissolution processes of PEEA with neutralization in water were described.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003960050344
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