UiO-67 Metal-organic framework immobilized Fe3+ catalyst for efficient Morita-Baylis-Hillman reaction

A solvothermal technique was used to prepare UiO-67, a metal-organic framework based on Zirconium; immobilized Fe3+ active sites were added using a facile post-synthetic modification method. The as-synthesized catalyst UiO-67@Fe...

Moisture- and mould-proof characteristics of surface modified wood for musical instrument soundboards

Wood is the main material used for musical instrument soundboard fabrication, for practical and cultural reasons. As a natural material, however, wood is easily degraded due to moisture or fungal corrosion. Most traditional wood protection methods were devised for structural materials, and may thus not be suitable for application in musical instrument soundboard materials. In the current study, a novel nanomaterial-based modification method was applied to wood. The surface of wood was coated with polyurethane and MgAl-layered double hydroxide nanosheets after a convenient impregnation process. The modified wood exhibited improved hydrophobicity and mould-resistance, while maintaining its acoustic properties. This modified wood may facilitate the construction of soundboards with longer lifespans.

Effect of Acetylation, Hydroxypropylation and Dual Acetylation-Hydroxypropylation on Physicochemical and Digestive Properties of Rice Starches with Different Amylose Content

Four rice (Oryza sativa L.) starches widely differing in amylose content were subjected to acetylation, hydroxypropylation, and dual modification involving acetylation followed by hydroxypropylation. The starches showed a higher affinity to hydroxypropyl substitution. However, acetylation caused a significant alteration in the glycosidic matrices. The changes in physicochemical properties were most prominent in the dual-modified samples. Hydroxypropylated and dual-modified granules showed greater swelling power with structural retention. Degrees of acetylation were high in the amorphous regions of waxy and low amylose starches (0.04 and 0.05). Minor granular swelling was observed under SEM. Substitution partially dissociated side-chain superhelices, lowering crystallinity values by 3.12-4.58%, however retaining the native A-type XRD patterns. Glycosidic dissociation and enhanced hydrophilicity caused a significant lowering of gelatinization temperature (To, Tp, Tc), enthalpy (H), and cooking time as observed from DSC and RVA results. Low setback viscosity and low syneresis during freeze-thaw cycles indicated the decreased tendency of modified starch chains to realign. Dual modified starches could be cooked to thinner and more precise pastes, which are highly resilient to retrogradation. Significant increases in enzyme-resistant RS and SDS (up to 20% of each) were recorded. The dual modification method could suitably alter the properties of starches for food use.