Advances in regenerated cellulosic aerogel from waste cotton textile for emerging multidimensional applications.

Rapid development of society and the improvement of people's living standards have stimulated people's keen interest in fashion clothing. This trend has led to the acceleration of new product innovation and the shortening of the lifespan for cotton fabrics, which has resulting in the accumulation of waste cotton textiles. Although cotton fibers can be degraded naturally, direct disposal not only causes a serious resource waste, but also brings serious environmental problems. Hence, it is significant to explore a cleaner and greener waste textile treatment method in the context of green and sustainable development. To realize the high-value utilization of cellulose II aerogel derived from waste cotton products, great efforts have been made and considerable progress has been achieved in the past few decades. However, few reviews systematically summarize the research progress and future challenges of preparing high-value-added regenerated cellulose aerogels via dissolving cotton and other cellulose wastes. Therefore, this article reviews the regenerated cellulose aerogels obtained through solvent methods, summarizes their structure, preparation strategies and application, aimed to promote the development of the waste textile industry and contributed to the realization of carbon neutrality.

A triple-crosslinking strategy for high-performance regenerated cellulose fibers derived from waste cotton textiles.

Regenerated cellulose fibers has attracted increasing attention for high-grade textile raw materials and industrial textiles, but the low mechanical property caused by differences in regenerated raw materials and production levels limits its commercial application in the product diversity. Herein, we proposed a novel triple-crosslinking strategy by coupling with hydrogen bonds, chemical crosslinking, and internal mineralization from multiple pulsed vapor phase infiltration (MPI) to improve the mechanical performance of regenerated cellulose fibers. A binary solvent composed of ionic liquid (IL) and dimethyl sulfoxide (DMSO) is used to dissolve waste cotton textile and then wet spinning. Dual-crosslinking is firstly achieved by coupling glutaraldehyde (GA) and cellulose reaction. Subsequently, a metal oxide is intentionally infiltrated into inner cellulosic through MPI technology to form a third form of crosslinking, accompanied by the ultra-thin metal oxide nano-layer onto the surface of regenerated cellulose fibers. Results showed that the triple-crosslinking strategy has increased the tensile stress of the fiber by 43.57 % to 287.03 MPa. In all, triple-crosslinking strategy provides a theoretical basis and technical approach for the reinforcement of weak fibers in waste cotton recycling, which is expected to accelerate the development of the waste textile recycling industry and promote of the added-value of regenerated products.

Demonstration of a microwave photonic synthetic aperture radar based on photonic-assisted signal generation and stretch processing.

A microwave photonic synthetic aperture radar (MWP SAR) is developed and experimentally demonstrated. In the transmitter, microwave photonic frequency doubling is used to generate a linearly-frequency-modulated (LFM) radar signal; while in the receiver, photonic stretch processing is employed to receive the reflection signal. The presented MWP SAR operates in Ku band with a bandwidth of 600MHz, and is evaluated through a series of inverse SAR imaging tests both in a microwave anechoic chamber and in a field trial. Its imaging performance verifies that the proposed MWP SAR works perfect and shows the potential of overcoming the conventional radar bandwidth bottleneck.