Delayed-onset Polymer Cross-linking using Functional Nitroxyls

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Authors

Hyslop, David

Date

2012-06-11

Type

thesis

Language

eng

Keyword

tempo , crosslink , polyethylene , cross-link , cure , delayed action , dicumyl peroxide , radical , nitroxyl , scorch

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Abstract

New polymer cure chemistry is described, wherein the onset of free radical cross-linking is delayed without compromising cure yields. The addition of an acrylate-functionalized nitroxyl, 4-acryloyloxy-2,2,6,6-tetramethylpiperidine-N-oxyl (AOTEMPO), to a peroxide-cure formulation quenches free radical activity during the initial stages of the cross-linking process, trapping alkyl radicals as alkoxyamines that bear acrylate functionality. Polymer cross-linking by macro-radical combination is suppressed until all nitroxyl is consumed, at which point radical oligomerization of polymer-bound acrylate groups generates the desired covalent network. As a result, cross-link density losses incurred during radical trapping are recovered during the oligomerization phase of the process. The effectiveness of this approach is demonstrated for a range of polymers, peroxide initiators, reaction temperatures and reagent loadings. Furthermore, AOTEMPO formulations are compared directly to other delayed-onset additives that are used in commercial practice.

Description

Thesis (Master, Chemical Engineering) -- Queen's University, 2012-06-11 10:09:20.848

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This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.

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