✦ LIBER ✦

Cyclization dynamics of polymers, 26. End-to-end cyclization of polystyrene in mixed solvents. Effect of chain length

✍ Scribed by Martinho, José M. G. ;Martinho, Maria Helena ;Winnik, Mitchell A. ;Beinert, Gérard

Publisher: Wiley (John Wiley & Sons)
Year: 1989
Weight: 520 KB
Volume: 15
Category: Article
ISSN: 0025-116X
DOI: 10.1002/macp.1989.020151989112

No coin nor oath required. For personal study only.

✦ Synopsis

Cyclization rate measurements were carried out on polystyrene chains of different molecular weights and labelled at both ends with I-pyrenyl groups, using as solvents cyclopentane (a thetasolvent), acetone (a poor solvent), and their mixtures. These mixtures exhibit a cosolvency effect for polystyrene. The results show that the rate constants for cyclization and ring-opening are solvent-and chain-length-dependent. This was interpreted in terms of the influence of excluded volume effects on these processes. The results indicate that the solvent giving the largest excluded volume effect is an equimolar mixture of cyclopentane and acetone, which agrees with the light scattering and viscometry results for polystyrene in cyclohexane/acetone mixtures.

📜 SIMILAR VOLUMES

Cyclization dynamics of polymers: 10 Syn

Cyclization dynamics of polymers: 10 Synthesis, fractionation, and fluorescent spectroscopy of pyrene end-capped polystyrenes

✍ Mitchell A. Winnik; A.E.C. Redpath; Katherine Paton; Jarda Danhelka 📂 Article 📅 1984 🏛 Elsevier Science 🌐 English ⚖ 1008 KB

Polarity effects of solvent mixtures in

Polarity effects of solvent mixtures in exciplexes formed on cyclization of polystyrene chains

✍ M.A. Winnik; H. Xu; J.M.G. Martinho 📂 Article 📅 1991 🏛 Elsevier Science 🌐 English ⚖ 347 KB

The effect of chain length on the mean v

The effect of chain length on the mean value of the end-to-end distance of a random-flight polymer chain adsorbed on a surface

✍ Anil Kumar; Santosh K. Gupta; Ratan Mohan 📂 Article 📅 1977 🏛 Elsevier Science 🌐 English ⚖ 415 KB

A general solution of the onedimensional random-walk probIem with an adsorbing barrier has been devefoped. For a given adsorption energy, 8, as the chain length is incx\*sed, the mean position of the free end of the molecule with respect to the surface, z, approaches the asymptotic values predicted

Cyclization dynamics of polymers: 9. The

Cyclization dynamics of polymers: 9. The effect of polymer concentration on the slowest internal relaxation mode of a labelled polystyrene chain

✍ A.E.C. Redpath; Mitchell A. Winnik 📂 Article 📅 1983 🏛 Elsevier Science 🌐 English ⚖ 558 KB

NMR Self-Diffusion of Associative Polyme

NMR Self-Diffusion of Associative Polymers in Aqueous Solution: The Influence of the Hydrocarbon End-Chain Length on the Polymer Transport Dynamics in Single- and Two-Component Mixtures

✍ S. Abrahmsén-Alami; P. Stilbs 📂 Article 📅 1997 🏛 Elsevier Science 🌐 English ⚖ 144 KB

tonian behavior at low shear rates with shear thinning only This paper presents diffusion studies of two ''model'' associative at relatively high shear rates. ## polymers (hydrophobically end-capped poly(ethylene oxide)) (AP) Numerous investigations with various techniques have differing in end-g