Université de Lyon, INSA LYON, Ingénierie des Matériaux Polymères IMP-UMR CNRS 5223 F 69621, Villeurbanne, France.
Université de Lyon, Université Claude Bernard Lyon 1, ISARA Lyon, BioDyMIA (Bioingénierie et Dynamique Microbienne Aux Interfaces Alimentaires), Equipe Mixte d'Accueil n°3733, IUT Lyon 1, Technopole Alimentec, Rue Henri de Boissieu, 01000 Bourg en Bresse, France.
Carbohydr Polym. 2019 Feb 15;206:674-684. doi: 10.1016/j.carbpol.2018.11.030. Epub 2018 Nov 16.
In this study, we report a simple, non-degrading and efficient homogeneous acylation of cellulose diacetate (CDA) by using a large panel of commercially available acylating aliphatic moieties, differing in their structure (fatty, ramified, bulky, cycloaliphatic, aromatic, more or less spaced from the cellulose backbone), in view of generating a library of well-defined cellulose mixed esters with enhanced thermoplasticity. As reflected by a lowering of the glass temperature (Tg), the covalent grafting confers an improved mobility to the cellulose chains, by disrupting the initial H-bonds. In particular, it appears that the gain in free volume is tailored by the substituent structure and that acylating reagents consisting in a terminal bulky moieties spaced from CDA chains by a linear chain efficiently separate macromolecular chains without generating detrimental stiffening interactions (low Tg around 125 °C). Moreover, free-standing films easily prepared by solvent casting exhibit relevant water transport properties, which are closely dictated and tuned by the water solubility of the cellulose mixed ester.
在这项研究中，我们报告了一种简单、非降解和高效的均相乙酰化纤维素二醋酸酯（CDA）的方法，使用了大量商业可得的酰化脂肪族部分，它们在结构上有所不同（脂肪族、支化、庞大、脂环族、芳香族、或多或少与纤维素主链隔开），旨在生成具有增强热塑性的一系列具有良好定义的纤维素混合酯。通过降低玻璃化转变温度（Tg）可以反映出，通过破坏初始氢键，共价接枝赋予纤维素链更好的迁移性。特别是，似乎是取代基结构决定了自由体积的增加，并且由通过线性链与 CDA 链隔开的末端庞大部分组成的酰化试剂有效地分离大分子链，而不会产生有害的增硬相互作用（约 125°C 的低 Tg）。此外，通过溶剂浇铸轻松制备的独立薄膜表现出相关的水分传输性能，这些性能由纤维素混合酯的水溶性紧密决定和调节。
