Enhanced mechanical performances of waterborne polyurethane loaded with lignosulfonate and its supramolecular complexes

Constructing an interaction in plant polyphenol-modified carbon fiber with amylopectin-based waterborne polyurethane sizing agent via hydrogen bonding to improve the interfacial performance of carbon fiber/nylon 6 composites

The adhesive strength between the sizing agent and carbon fiber (CF) plays a crucial role in improving the interfacial properties of composites, while such a vital aspect has been consistently disregarded. In this study, a hyperbranched waterborne polyurethane (HWPU) sizing agent was synthesized from biogenetically raw materials including gallic acid, l-Lysine diisocyanate and amylopectin. Concurrently, hydrogen-bonded cross-linked network structures were established utilizing a botanical polyphenol tannin as coupling agent to effectively connect CF with HWPU. This meticulous process yielded CF/nylon 6 composites with improved properties and their mechanical characteristics were systematically investigated. The findings showcased a noteworthy boost in flexural strength and interlaminar shear strength (ILSS), showing enhancements of 54.6 % and 61.4 %, respectively, surpassing those of untreated CF. Furthermore, the interfacial shear strength (IFSS) test indicated a remarkable 70.3 % improvement. This approach presents a highly promising concept aimed at developing sustainable green waterborne polyurethane sizing agent and improving the interfacial performance of CF composite materials.

Preparation of avermectin microcapsules with anti-photodegradation and slow-release by the assembly of lignin derivatives

A facile, environmentally friendly, and low-cost strategy for affording stability and the slow-release of avermectin based on self-assembly of lignin derivatives is described.

Consecutively preparing d-xylose, organosolv lignin, and amorphous ultrafine silica from rice husk

Rice husk is an abundant agricultural by-product reaching the output of 80 million tons annually in the world. The most common treatment method of rice husk is burning or burying, which caused serious air pollution and resource waste. In order to solve this problem, a new method is proposed to comprehensively utilize the rice husk in this paper. Firstly, the D-xylose was prepared from the semicellulose via dilute acid hydrolysis. Secondly, the lignin was separated via organic solvent pulping from the residue. Finally, the amorphous ultrafine silica was prepared via pyrolysis of the residue produced in the second process. In this way, the three main contents of rice husk (semicellulose, lignin, and silica) are consecutively converted to three fine chemicals, without solid waste produced. The yields of D-xylose and organosolv lignin reach 58.2% and 58.5%, respectively. The purity and specific surface of amorphous ultrafine silica reach 99.92% and 225.20 m²/g.

Preparing spherical lignin from rice husk

Lignin is one of the important branched amorphous polymers, which generally has the irregular and fractal morphology. The preparation of regular sphere of lignin needs long steps and special conditions. In this study, the regular sphere of lignin can be simply prepared from rice husk (RH) under certain conditions. Namely, RH is mixed with 35% ethanol aqueous solution in the proportion of 1:10 (g:mL), non-isothermally heated to 493 K and kept for 5 h. After filtration and air-drying at room temperature, the regular lignin sphere with the diameter of 100-400 nm is obtained. The regular sphere of lignin has the potential utilization in fields such as reactive functional materials, photo sensing materials and surface active materials in cosmetics. The mechanism of formation of the regular spherical lignin is proposed and discussed in this paper.