Toughen and Strengthen Alginate Fiber by Incorporation of Polyethylene Glycol Grafted Cellulose Nanocrystals

Alginate fibers have great potential in many applications, such as medical dressings, surgical sutures, and masks, etc. owing to their good biocompatibility and other properties. However, for alginate fibers prepared by wet spinning, the fibers have disadvantages such as low strength, poor toughness, and brittleness. Herein, a simple, scalable, and cost-effective blending spinning strategy was developed to produce the alginate composite fibers with excellent mechanical properties. Cellulose nanocrystals (CNCs) were incorporated directly in the wet spinning solution to improve its strength, wherein the CNCs were prepared from waste cotton fabrics. Polyethylene glycol (PEG) molecular chain was grafted onto the CNC surface to be used as a plasticizer while increasing the dispersibility of CNCs in alginate matrix. It was worth noting that modification of alginate fibers with PEG grafted cellulose nanocrystals (CNC-g-PEG) enhanced the tensile strength and elongation at break, simultaneously. In addition, the CNC-g-PEG modified alginate fibers exhibited improved salt tolerance and reduced water absorbency. This work may make high-value utilization of waste cotton fabrics, and pave the way for the development of high-performance, green alginate fibers.

Tensile Strength and Density Evaluation of Composites from Waste Cotton Fabrics and High-Density Polyethylene (HDPE): Contributions to the Composite Industry and a Cleaner Environment

The growth of the textile industry and the massive use of plastic-based materials create economic growth, but it produces waste from post-use, such as clothing waste from cotton fabrics and HDPE that can be recycled and combined as composite materials. Therefore, an experiment was carried out to investigate and analyze the effect of the fiber volume fraction of waste cotton fabric (1.5%, 3.5%, 4.5%, 6%, and 7.5%) with straight fiber arrangement on the tensile strength and density. From the test results, a tensile strength of 178.4 MPa and 182.6 MPa was obtained for yield and max stress, respectively at a fiber volume fraction of 7.5%. Meanwhile, the highest density of 0.95 g/cm3 was obtained at 1.5% fiber volume fraction. The fracture macroscopic view of the specimen shows a resilience fracture (uneven and appears stringy). Although the strength of this composite cannot yet compete with the new composite material, it has a decent environmental contribution. Considering the availability of waste cotton fabrics and HDPE, it promises to be produced as a low-strength composite for construction, ornamentation, or coatings.

Environmentally Friendly Flexible Strain Sensor from Waste Cotton Fabrics and Natural Rubber Latex

A green approach was successfully developed to fabricate flexible sensors by utilizing carbonized waste cotton fabrics in combination with natural rubber latex. Waste cotton fabrics were firstly carbonized by heat treatment in the nitrogen atmosphere before they were combined with natural rubber latex using three methods, i.e., vacuum bagging, negative pressure adsorption and drop coating. After impregnation with natural rubber, the carbonized cotton maintained the fabric structure and showed good conductivity. More importantly, the electric resistance of the textile composites changed with the tensile strain. The cyclic stretching-releasing tests indicated that the prepared wearable flexible strain sensors were sensitive to strain and stable under cyclic loading. The flexible strain sensor also demonstrated the capability of monitoring human finger and arm motion.