Synthesis, characterization, and catalytic oxidation of styrene, cyclohexene, allylbenzene, and cis-cyclooctene by recyclable polymer-grafted Schiff base complexes of vanadium(IV)

Functionalization of chitosan and its application in flame retardants: A review

In recent years, bio-based flame retardants have gained significant attention as sustainable alternatives, achieving important breakthroughs in flame retardancy and becoming a key focus for future development. Derived from biomass, chitosan (CS) has been widely used in the field of advanced functional materials. However, in the field of flame retardancy, chitosan alone shows limited effectiveness, leading researchers to explore its reactive functional groups for creating multifunctional flame retardant chitosan composites (FRCC). This review examines FRCC modifications, focusing on how physical and chemical techniques enhance flame retardancy based on combustion mechanisms. Particular emphasis is placed on the impact of embedding flame-retardant elements. Additionally, this paper outlines FRCC performance characteristics, addressing operational requirements in varied environments, and discusses key challenges. This study offers researchers a comprehensive overview of FRCC, serving as a valuable resource for ongoing research and development.

Preparation and characterization of the bonding performance of a starch-based water resistance adhesive by Schiff base reaction

Starch is one of the important raw materials for the preparation of biomass adhesives for its good viscosity and low-cost properties. However, the drawbacks of poor water resistance and bonding performance seriously restrict its application in the wood industry. To resolve those problems, an environment-friendly renewable, and high water resistance starch-based adhesive (OSTH) was prepared with oxidized starch and hexanediamine by Schiff base reaction. In order to optimize the adhesive preparation process, the effect of different oxidation times and oxidant addition on the mechanical performance of plywood were investigated. In addition, the curing behavior characteristics, thermomechanical properties, and thermal stability of the OSTH adhesives were analyzed by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TG). Fourier-transform infrared (FTIR) spectrometry and Liquid Chromatography-Mass Spectrometry (LC-MS) were used to explain the reaction mechanisms involved. The results show this adhesive has an excellent bonding performance at the oxidation time of 12 h with 11 % (w/w, dry starch basis) NaIO4 as an oxidant. The dry shear strength, 24-hour cold water, and 3-hour hot water (63 °C) soaking shear strength of the plywood bonded with this resin were respectively 1.87 MPa, 0.96 MPa, and 0.91 MPa, which satisfied the standard requirement of GB/T 9846-2015 (≥0.7 MPa). Thus, this study provided a potential strategy to prepare starch-based wood adhesives with good bonding performance and water resistance.

Macroporous polystyrene degraded and functionalized chromium MPS-Cr(iii)-alen complex as a sustainable porous catalyst for CO2 fixation under atmospheric pressure and selective oxidation of aromatic alkenes

The benign synthesis of porous polystyrene supported chromium(iii) catalyst has been carried out for the production of cyclic carbonates via CO₂ fixation under atm. pressure and for the selective oxidation of aromatic alkenes under mild conditions.