Reversible cross-linking by complex formation. Polymers containing 2-hydroxybenzoic acid residues

Braun, Dietrich; Boudevska, Hrisanta

doi:10.1016/0014-3057(76)90010-0

Cited by 16 publications

(5 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, polymers bearing dienes and dienophiles undergo reversible cross-linking reactions, 7 and nitrososubstituted polymers undergo gelation upon formation of nitroso dimers. 8 Other reactions that have been used as mechanisms for cross-linking include anhydride exchange, 9,10 complex formation, 11 and disulfide formation. 12 Photochemically labile interactions are also used to reversibly cross-link polymers.…”

Section: Introductionmentioning

confidence: 99%

Photochemical Cross-Linking of Poly(ethylene terephthalate-co-2,6-anthracenedicarboxylate)

et al. 2000

View full text Add to dashboard Cite

Poly(ethylene terephthalate) copolymers containing 2,6-anthracenedicarboxylate structural units are chain extended and cross-linked by irradiation at 350 nm. The cross-linked materials were characterized by NMR, UV−vis, DSC, and dilute solution viscometry. The cross-linking is attributed to face-to-face dimerization of the anthracene units and radical reactions. Model anthracene photodimers are cleaved in solid films of PET by irradiation at 254 nm, but polymeric anthracene photodimerization reactions are irreversible under these conditions. The combination of irreversible anthracene photodimerization and irreversible radical reactions renders the cross-links permanent.

show abstract

Section: Introductionmentioning

confidence: 99%

Photochemical Cross-Linking of Poly(ethylene terephthalate-co-2,6-anthracenedicarboxylate)

et al. 2000

View full text Add to dashboard Cite

show abstract

“…Coordination chemistry typically features bonds that are intermediate in bond energy between covalent bond energy and other non-covalent interaction energies (for example, van der Waals interactions and hydrogen bonding) 1 . Such bonds have been used extensively for the formation of supramolecular polymer networks/gels 2 – 17 , metal–organic cages (MOCs) 18 – 25 and metal–organic frameworks (MOFs) 26 – 28 ; these important classes of materials feature an array of exciting, complementary properties. Materials that incorporate structural features that blend these classes of materials not only capitalize on their individual positive qualities, but also, by way of synergy, potentially exhibit unprecedented and valuable properties 29 – 31 .…”

mentioning

confidence: 99%

Highly branched and loop-rich gels via formation of metal–organic cages linked by polymers

et al. 2015

View full text Add to dashboard Cite

Gels formed via metal–ligand coordination typically have very low branch functionality, f, as they consist of ∼2–3 polymer chains linked to single metal ions that serve as junctions. Thus, these materials are very soft and unable to withstand network defects such as dangling ends and loops. We report here a new class of gels assembled from polymeric ligands and metal-organic cages (MOCs) as junctions. The resulting ‘polyMOC’ gels are precisely tunable and may feature increased branch functionality. We show two examples of such polyMOCs: a gel with a low f based on a M2L4 paddlewheel cluster junction and a compositionally isomeric one of higher f based on a M12L24 cage. The latter features large shear moduli, but also a very large number of elastically inactive loop defects that we subsequently exchanged for functional ligands, with no impact on the gel's shear modulus. Such a ligand substitution is not possible in gels of low f, including the M2L4-based polyMOC.

show abstract

“…The distance between HA groups on the same chain, r(ring), is a function of the mole fraction of HA units in the copolymer and the dimensions of the copolymer as affected by the solvent. On the assumption that the polymer in solution is a random coil, the distance r(ring) can be calculated from eq 5 and 6, where r0 is the root-r02 = C"nl2 (5) / (ring) = r0a (6) mean-square distance between neighboring HA groups, n is the average number of chemical bonds separating the HA groups, l is the bond distance (0.154 nm), nl2 gives the dimension of the random walk model, C" is the characteristic ratio and corrects for the increase in size of a polymer over the random walk model as a result of short-range effects, and a is the expansion factor to take into account the increase in size due to polymer-solvent interactions.…”

Section: Resultsmentioning

confidence: 99%

Crosslinking of hydroxamic acid copolymers through iron chelation

Rosthauser¹,

Winston²

1981

Macromolecules

View full text Add to dashboard Cite

Polymers bearing widely spaced hydroxamic acid (HA) groups were synthesized by copolymerization of the iV-hydroxysuccinimide ester of iV-methacryloyl-d-alanine with acrylamide, followed by treatment with methylhydroxylamine. The HA content of the three copolymers was measured spectrophotometrically, using the 504 nm absorption of the 1:1 HA-Fem complex. The copolymers contained 0.749, 0.259, and 1.80 mol % HA units, and their intrinsic viscosities in water at 30 °C were 0.58,1.86, and 0.52 dL/g, respectively. The effect of the HA:Fe ratio and the overall polymer concentration on the intrinsic viscosity was studied. At high concentrations of polymer, addition of iron (III) caused [ ] to increase up to a maximum at an HA:Fe ratio of 3:1. Below the 3:1 ratio, [ ] decreased rapidly back to the value of the original solution. At low concentrations of polymer, addition of iron caused a decrease in [ ] to a minimum at an HA:Fe ratio of 3:1. Below 3:1, [ ] increased back to the values of the original solution. At higher concentrations, the probability of intermolecular complexation is high, resulting in cross-linking and increasing [??]. At lower

show abstract

Reversible cross-linking by complex formation. Polymers containing 2-hydroxybenzoic acid residues

Cited by 16 publications

References 4 publications

Photochemical Cross-Linking of Poly(ethylene terephthalate-co-2,6-anthracenedicarboxylate)

Photochemical Cross-Linking of Poly(ethylene terephthalate-co-2,6-anthracenedicarboxylate)

Highly branched and loop-rich gels via formation of metal–organic cages linked by polymers

Crosslinking of hydroxamic acid copolymers through iron chelation

Contact Info

Product

Resources

About