Chemical Reactivity of Copolymers

Diad, triad, and pentad sequence‐distribution analysis of acrylonitrile–vinylidene chloride model copolymers by 13C‐NMR

“…In the area of chain-growth copolymerization measured copolymer sequence distributions have been interpreted in terms of the relative rates of the various propagation steps in terminal, penultimate, and other copolymerization mode l~.~-~ Relationships between sequence distribution and copolymer properties, both physical and chemical, have also been identified; for example, the effect of sequence distribution on the glass transition temperatures of a wide range of materials was the subject of a recent review a r t i~l e .~ Also, a number of studies have demonstrated that the reactivity of functional groups in polymer modification reactions are strongly affected by the arrangement of monomer units in the chain. [6][7][8] NMR spectroscopy has been an especially helpful tool in the determination of sequencing and tacticity in polymers. Although chain microstructure has a wide-range effect on the physical and chemical properties of polymers, few analytical techniques other than nuclear magnetic resonance (NMR) can be used to measure tacticity or sequencing quantitati~ely.~J~ Most sequence studies by NMR have involved the lH nucleus as a result of its relatively high sensitivity.…”

Enhanced Site Isolation in Cross-Link-Functionalized Polystyrene Networks: Mobility Studies Using Steady-State Fluorescence and ESR Techniques

“…Copolymers of styrene and DVB are known to be heterogeneously cross-linked, and unless C·Tr is similar in this respect, it is likely that the structures of the networks will differ. Such differences are known to have profound effects upon site accessibility and reactivity . We attempted to address these potential differences by adding a small aliquot of methanol to compete with 3 for sites.…”