Graduate Department of Forestry, John H. Daniels Faculty of Architecture, Landscape and Design, University of Toronto, 33 Willcocks Street, Toronto, ON M5S 3B3, Canada.
Department of Chemical Engineering & Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada.
Carbohydr Polym. 2020 Apr 15;234:115892. doi: 10.1016/j.carbpol.2020.115892. Epub 2020 Jan 19.
The limited reactivity of starch towards maleic anhydride (MA) affords maleate with a low degree of MA substitutions (CC and COOH groups). In this study, we investigated the relationship between the starch structure, controlled by its amylose (AM)/amylopectin (AP) ratio, and the DS of starch maleates using C[mim]Cl as the recyclable media, and catalyst. The results indicated that starches with varying AM/AP ratio produced maleates with comparable CC groups (DS = 0.06-0.07). Following dissolution, the high amylose (DS = 1.17, yield = 69.2 %) and regular starches (DS = 1.17; yield = 59.3 %) produced high DS maleates (COOH groups) at MA/AGU ratio of 12:1 (80 °C, 10 min). Comparatively, DS value of waxy starch maleates (DS = 0.88, yield = 59.3 %) was lower than AM-based starches, possibly due to the crosslinking tendency of AP branches consisting of carboxylic end-groups. Interestingly, DS value for EHCS (1.17) ranged between its bulk (DS: 0.06) and surface distribution of MA (DSS 1.7); therefore, we considered it reliable for future reference.
淀粉与马来酸酐（MA）的反应性有限，只能得到 MA 取代度较低的马来酸盐（CC 和 COOH 基团）。在这项研究中，我们研究了淀粉结构与淀粉马来酸盐的 DS 之间的关系，淀粉结构由其直链淀粉（AM）/支链淀粉（AP）的比例控制，使用 C[mim]Cl 作为可回收的介质和催化剂。结果表明，具有不同 AM/AP 比例的淀粉产生的马来酸盐具有相似的 CC 基团（DS=0.06-0.07）。在溶解后，高直链淀粉（DS=1.17，产率=69.2%）和常规淀粉（DS=1.17；产率=59.3%）在 MA/AGU 比为 12:1（80°C，10 min）的情况下产生高 DS 马来酸盐（COOH 基团）。相比之下，蜡质淀粉马来酸盐的 DS 值（DS=0.88，产率=59.3%）低于 AM 为基础的淀粉，这可能是由于羧酸端基的 AP 支链的交联倾向。有趣的是，EHCS 的 DS 值（1.17）介于其整体（DS：0.06）和 MA 表面分布（DSS 1.7）之间；因此，我们认为它是可靠的，可用于未来参考。
