Cationic grafting of olefins from PVC: The effect of reaction conditions |
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Authors: | Zhengjie Pi J P Kennedy |
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Institution: | Institute of Polymer Science, The University of Akron, Akron, Ohio 44325-3909 |
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Abstract: | The cationic grafting of isobutylene, styrene, α-methylstyrene, and β-pinene from a poly(vinyl chloride) (PVC) backbone was investigated. Grafting-from was induced by Et2AlCl in 1,2-dichloroethane and methylene dichloride solutions from 20 to ?70 °C. The effects of temperature and proton trap 2,6-di-tert-butylpyridine (DtBP)] on grafting-from efficiency (Geff), extent of grafting, branch length (molecular weight), and number of branches per PVC molecule were determined. Reducing the temperature invariably increased the Geff and the molecular weight of polyisobutylene, polystyrene, poly(α-methylstyrene), and poly(β-pinene) branches attached to PVC. The magnitude of the effects was different with the various olefins and depended on the reaction conditions. The effect of DtBP was examined in the 5 × 10?4–4 × 10?3 mol/L range. By increasing the DtBP concentration the Geff increased; however, the number-average molecular weight of the grafted branches decreased. The lengths of the grafted branches can be controlled, and Geff's close to 100% were obtained. The fact that the proton trap reduced the molecular weights of grafted branches suggests that besides proton scavenging, DtBP may also abstract protons from the growing carbenium ion site. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1675–1680, 2001 |
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Keywords: | functionalized poly(vinyl chloride) cationic grafting from PVC PVC grafts effect of proton trap temperature/molecular weight effects in cationic grafting |
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