Alkyne Creation in Aliphatic Polymers: Influence of Side Groups

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• 作者：Yvette Ngono-Ravache ; Dominique Corbin ; Christophe Gaté ; Micka&euml ; l Mé ; lot ; Emmanuel Balanzat
• 刊名：Journal of Physical Chemistry B
• 出版年：2007
• 出版时间：March 22, 2007
• 年：2007
• 卷：111
• 期：11
• 页码：2813 - 2819
• 全文大小：111K
• 年卷期：v.111,no.11(March 22, 2007)
• ISSN：1520-5207

文摘

In this article, we focus on the influence of side groups on terminal alkyne creation, in aliphatic polymerssubmitted to swift heavy ions, under vacuum. Terminal alkyne creation was compared in polyethylene andin substituted polymers. We selected two classes of side groups: alkyl groups, which differed in their length(polypropylene and polybutene) and allyl groups, which were linear (EPDMh) or cyclic (EPDMn). Irradiatedsamples were analyzed using Fourier transform IR spectroscopy, in the transmission mode, at room temperature.Alkynes are created when the electronic stopping power, (dE/dx)_e, exceeds a threshold value. This thresholdvalue was moderately influenced by the presence of an alkyl side chain but was clearly reduced in the presenceof C=C bonds on the side chain. Nevertheless, in all-saturated polymers, below the (dE/dx)_e threshold, terminalalkyne formation is observed after a latent dose, rather independently of the side-chain length and directlyrelated to the formation of radiation-induced double bonds prior to alkyne formation. Under S ion irradiation,the radiation chemical yield G₀ value obtained in EPDMh was 4 times the value of G₀ in PE. This effect isunderstandable only if important energy transfers, from the backbone to C=C double bonds, are considered.