Chemical Modification of Starch via Etherification with Methyl Methacrylate

Raman imaging: An indispensable technique to comprehend the functionalization of lignocellulosic material

With the increasing demands on sustainability in the material science and engineering landscape, the use of wood, a renewable and biodegradable material, for new material development has drawn increasing attentions in the materials science community. To promote the development of new wood-based materials, it is critical to understanding not only wood's hierarchical structure from molecule to macroscale level, but also the interactions of wood with other materials and chemicals upon modification and functionalization. In this review, we discuss the recent advances in the Raman imaging technique, a new approach that combines spectroscopy and microscopy, in wood characterization and structural evolution monitoring during functionalization. We introduce the principles of Raman spectroscopy and common Raman instrumentations. We survey the use of traditional Raman spectroscopy for lignocellulosic material characterizations including cellulose crystallinity determination, holocellulose discrimination, and lignin substructure evaluation. We briefly review the recent studies on wood property enhancement and functional wood-based material development through wood modification including thermal treatment, acetylation, furfurylation, methacrylation, delignification. Subsequently, we highlight the use of the Raman imaging for visualization, spatial and temporal distribution of wood cell wall structure, as well as the microstructure evolution upon functionalization. Finally, we discuss the future prospects of the field.

Catalytic Transesterification of Starch with Plant Oils: A Sustainable and Efficient Route to Fatty Acid Starch Esters

The transesterification of maize starch with olive oil or high oleic sunflower oil was studied under homogeneous conditions in the presence of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as catalyst. Most importantly, this method used two renewable resources directly, without any pretreatment or derivatization, for the synthesis of polymeric materials with desirable properties. Moreover, the solvent, oils, and catalyst could be recovered through facile work-up and reused for further modifications. The obtained fatty acid starch esters (FASEs) were highly soluble in common organic solvents and were thoroughly characterized. Degrees of substitution (DS) were calculated using ³¹ P NMR spectroscopy, and DS values of approximately 1.3 were obtained. Differential scanning calorimetry analysis revealed thermal transitions of the modified starches at approximately 80-90 °C. Films were produced from these FASEs, and their hydrophobic surfaces were characterized using contact-angle measurements. Furthermore, mechanical properties were examined using tensile strength measurements and showed approximately 40 and 80 % elongation at break for modified maize starch and modified amylose from maize, respectively.