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Synthesis of 1,2-bis(2-oxazolinyl-2)ethane and its application as chain extender for poly(ethylene terephthalate) Loontjens, Ton; Belt, Wil; Stanssens, Dirk; Weerts, Pierre Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Loontjens, T., Belt, W., Stanssens, D., & Weerts, P. (1993). Synthesis of 1,2-bis(2-oxazolinyl-2)ethane and its application as chain extender for poly(ethylene terephthalate). Polymer Bulletin, 30(1), 13-18. DOI: 10.1007/BF00296228 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. SummaryThe reaction of ethanolamine (EA) with nitriles is a general route to prepare oxazolines. However, in case of vicinal nitrile groups, cyclic imidines are formed. It is shown, that succinonitrile gives with EA mainly l-(hydroxyethyl)-2,5-bis-(hydroxyethylimine) azacyclopentane (= triol). The corresponding 1,2 bis-(2-oxazolinyl-2) ethane (BOXE) is formed by heating the triol. BOXE can be used as chain extender of poly(ethylene terephthalate) (PET). If PET is heated with BOXE at 270 ~ the viscosity increases first. However, on prolonged heating the viscosity decreases again, which can not be ascribed to the normal degradation processes. Therefore, a mechanism is proposed ill which the chain scission takes place in the newly formed bridge.

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A synthetic method was found to prepare 1,2‐bis‐(2‐oxazolinyl‐2)ethane (BOXE) from succinonitrile and ethanolamine. Succinonitrile is a vicinal dinitrile, which forms with ethanolamine succinimidine. This imidine can be converted in good yield into the corresponding BOXE by heating it while stripping off the excess of ethanolamine. Bisoxazolines react with the carboxylic endgroups of PET, giving a strong increase in viscosity. The efficiency of this chain extension reaction depends on the structure of the bisoxazoline. BOXE gives a sharp rise in the viscosity of PET after 2.5 min at 270 °C. After prolonged heating the viscosity decreases again, even under the level of the blank. A mechanism is given which describes this unusual behaviour. It is proposed that chain scission takes places in the newly formed esteramide bridge.

Synthesis of α-hydroxy-ω-amino poly(ethylene oxide) and its use in reaction injection moulding (RIM)