Fraunhofer Institute for Applied Polymer Research, Division Biopolymers, Department Starch/Molecular Structure, Geiselbergstr. 69, 14476 Potsdam, Germany.
Carbohydr Polym. 2013 Oct 15;98(1):208-16. doi: 10.1016/j.carbpol.2013.05.086. Epub 2013 Jun 7.
Being completely bio-based, fatty acid starch esters (FASEs) are attractive materials that represent an alternative to crude oil-based plastics. In this study, two synthesis methods were compared in terms of their efficiency, toxicity and, especially, product solubility with starch laurate (C12) as model compound. Laurates (DS>2) were obtained through transesterification of fatty acid vinylesters in DMSO or reaction with fatty acid chlorides in pyridine. The latter lead to higher DS-values in a shorter reaction time. But due to the much better solubility of the products compared to lauroyl chloride esterified ones, vinylester-transesterification was preferred to optimize reaction parameters, where reaction time could be shortened to 2h. FASEs C6-C18 were also successfully prepared via transesterification. To determine the DS of the resulting starch laurates, the efficient ATR-IR method was compared with common methods (elementary analysis, (1)H NMR). Molar masses (Mw) of the highly soluble starch laurates were analyzed using SEC-MALLS (THF). High recovery rates (>80%) attest to the outstanding solubility of products obtained through transesterification, caused by a slight disintegration during synthesis. Particle size distributions (DLS) demonstrated stable dissolutions in CHCl3 of vinyl laurate esterified - contrary to lauroyl chloride esterified starch. For all highly soluble FASEs (C6-C18), formation of concentrated solutions (10 wt%) is feasible.
完全基于生物的脂肪酸淀粉酯（FASE）是一种有吸引力的材料，它是石油基塑料的替代品。在这项研究中，以月桂酸淀粉酯（C12）为模型化合物，比较了两种合成方法在效率、毒性，特别是产品溶解度方面的差异。通过脂肪酸乙烯酯在 DMSO 中的酯交换或脂肪酸氯化物在吡啶中的反应，可以得到 DS>2 的月桂酸酯。后者在更短的反应时间内可以得到更高的 DS 值。但是，由于产物的溶解度比月桂酰氯酯化产物好得多，因此优先选择乙烯酯酯交换来优化反应参数，其中反应时间可以缩短至 2 小时。还通过酯交换成功制备了 C6-C18 的 FASE。为了确定所得淀粉月桂酸酯的 DS 值，与常用方法（元素分析、（1）H NMR）相比，对高效 ATR-IR 方法进行了比较。使用 SEC-MALLS（THF）分析了高度可溶的淀粉月桂酸酯的摩尔质量（Mw）。高回收率（>80%）证明了通过酯交换获得的产物具有出色的溶解度，这是由于在合成过程中发生了轻微的崩解。动态光散射（DLS）表明，与月桂酰氯酯化淀粉相反，乙烯基月桂酸酯酯化的在 CHCl3 中稳定溶解。对于所有高水溶性的 FASE（C6-C18），都可以形成浓度为 10wt%的溶液。
