Schoon Ina, Kluge Marcel, Eschig Steven, Robert Tobias
Fraunhofer Institute for Wood Research⁻Wilhelm-Klauditz-Institut WKI, Bienroder Weg 54E, 38108 Braunschweig, Germany.
Polymers (Basel). 2017 Dec 9;9(12):693. doi: 10.3390/polym9120693.
Bio-based unsaturated polyester resins derived from itaconic acid can be an alternative to established resins of this type in the field of radical-curing resins. However, one of the challenges of these polyester itaconates is the somewhat more elaborate synthetic process, especially under polycondensation conditions used on an industrial scale. The α,β-unsaturated double bond of the itaconic acid is prone to side reactions that can lead to the gelation of the polyester resin under standard conditions. This is especially true when bio-based diols such as 1,3-propanediol or 1,4-butanediol are used to obtain resins that are 100% derived from renewable resources. It was observed in earlier studies that high amounts of these aliphatic diols in the polyester lead to low conversion and gelation of the resins. In this work, a catalytic study using different diols was performed in order to elucidate the reasons for this behavior. It was shown that the choice of catalyst has a crucial influence on the side reactions occurring during the polycondensation reactions. In addition, the side reactions taking place were identified and suppressed. These results will allow for the synthesis of polyester itaconates on a larger scale, setting the stage for their industrial application.
源自衣康酸的生物基不饱和聚酯树脂可在自由基固化树脂领域替代此类现有树脂。然而，这些衣康酸聚酯面临的挑战之一是合成过程略显复杂，尤其是在工业规模使用的缩聚条件下。衣康酸的α,β-不饱和双键容易发生副反应，在标准条件下可能导致聚酯树脂凝胶化。当使用诸如1,3-丙二醇或1,4-丁二醇等生物基二醇来获得完全源自可再生资源的树脂时，情况尤其如此。早期研究观察到，聚酯中大量的这些脂肪族二醇会导致树脂转化率低和凝胶化。在这项工作中，进行了一项使用不同二醇的催化研究，以阐明这种行为的原因。结果表明，催化剂的选择对缩聚反应过程中发生的副反应有至关重要的影响。此外，识别并抑制了发生的副反应。这些结果将使大规模合成衣康酸聚酯成为可能，为其工业应用奠定基础。
