Reactivity of poly(ethylene oxide) derivatives with various placements of functional groups in the polymer chain

✍ Scribed by I.N. Topchieva; N.V. Efremova; S.V. Osipova

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 250 KB
• Volume: 27
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(91)90133-9

✦ Synopsis

Reactivity of poly(ethylene oxide) (PEO) derivatives with different localization of functional groups in the polymer chain has been studied. The kinetics of alkaline hydrolysis of 2,4-dinitrophenyl PEO derivatives of different molecular masses having one or two nitroaromatic groups at the ends of the chain have been investigated. It has been shown that in all cases a first-order kinetic equation is satisfied. The reaction rate constant depends neither on the functionality of the dinitrophenyl derivatives nor on the molecular mass (within the range 3000--49,000); it is (9.6 + 1.3). 10 -3 min -~ at 50 ° in 0.1 M alkali solution. The functional PEO derivatives containing the reactive groups in the main chain are represented by hydroperoxy(HP)-derivatives. The reduction of HP-groups in the polymers with potassium iodide in an acid medium has been studied. It has been demonstrated that the reaction rate constant is (2.2 +_ 0.2) • 10 -~ min -t at 37 ° in 0.18 M KI and does not depend on the polymer molecular mass within the range 1500-15,000. Thus, using two types of PEO derivatives as examples, in which the reactive groups are either end or middle fragments of the polymer chain, we have derived simple kinetic laws governing the process of chemical modification and demonstrated agreement with the Flory principle.