Preparation of straw/PLA composites with excellent flame retardancy based on deep eutectic solvent sulfonation.

There have been numerous studies on flame retardant modification of natural fiber/PLA composite materials due to the demand for applications. However, the existing flame retardant modification methods mostly involve adding flame retardants, which have a negative impact on the mechanical properties. Based on this, this study aims to introduce sulfonic groups into the cellulose of straw fibers via modification with a sulfamic acid-based deep eutectic solvent (SDES), thereby achieving flame retardance without affecting the inherent mechanical properties of the composite material. The performance enhancement of DS/PLA is manifested in the following specific aspects: the LOI reaches 36.53 %, the thermal stability is improved from 7.8 % of the residual carbon of PS/PLA to 38.4 %, and the tensile modulus is increased by 69.5 %. The preparation scheme for straw/PLA composite materials in this study is simple, economical, and efficient, and the flame retardant performance of the composite material is excellent, providing valuable references for flame retardant modification of natural fiber/plastic composite materials.

Preparation of environmentally friendly, high strength, adhesion and stability hydrogel based on lignocellulose framework.

Hydrogels are extensively utilized in the fields of electronic skin, environmental monitoring, biological dressings due to their excellent flexibility and conductivity. However, traditional hydrogel materials possess drawbacks such as environmental toxicity, low strength, poor stability, and water loss deactivation, which limited its frequent applications. Here, a flexible conductive hydrogel called wood-based DES hydrogel (WDH) with high strength, high adhesion, high stability, and high sensitivity was successfully synthesized by using environmentally friendly lignocellulose as skeleton and deep eutectic solvent as matrix. The strength of WDH prepared from lignocellulose framework is approximately 50 times higher than poly deep eutectic solvent hydrogel, and about 4.5 times higher than that prepared from cellulose skeleton. The WDH exhibits stable adhesion to most common materials and demonstrates exceptional dimensional stability. Its conductivity remains unaffected by water, even after prolonged exposure to air, maintaining a value of 0.0245 S/m. The anisotropy inherent in the system results in three distinct linear sensing intervals for WDH, exhibiting a maximum sensitivity of 5.45. This paper verified the advantages of lignocellulose framework in improving the strength and stability of hydrogels, which provided a new strategy for the development of sensor materials.