Xiaoqing Guo

Enhanced mechanical and thermal properties of regenerated cellulose/graphene composite fibers

In this study, a wet spinning method was applied to fabricate regenerated cellulose fibers filled with low graphene loading which was systematically characterized by SEM, TEM, FTIR and XRD techniques. Subsequently, the mechanical and thermal properties of the resulting fibers were investigated. With only 0.2 wt% loading of graphene, a ∼ 50% improvement of tensile strength and 25% enhancement of Youngs modulus were obtained and the modified Halpin-Tsai model was built to predict the mechanical properties of composite fibers. Thermal analysis of the composite fibers showed remarkably enhanced thermal stability and dynamic heat transfer performance of graphene-filled cellulose composite fiber, also, the presence of graphene oxide can significantly enhance the thermal conductivity of the composite fiber. This work provided a facile way to improve mechanical and thermal properties of regenerated cellulose fibers. The resultant composite fibers have potential application in thermal insulation and reinforced fibrous materials.

Antimicrobial fibers based on chitosan and polyvinyl-alcohol

A series of antimicrobial fibers with different weight ratio of chitosan (CS) and polyvinyl alcohol (PVA) were fabricated via a primarily industrialized trail of wet-spinning method, and the morphology and structure of the resulting fibers were studied with the aid of scanning electron micrography (SEM), infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The CP60 blend fiber (60 % chitosan content) was confirmed as the best optimal sample among the blend fibers owing to strong intermolecular hydrogen bonds between PVA and chitosan and showed the maximum mechanical, antistatic, moisture absorption/desorption properties. The CP60 also exhibited good antimicrobial effects against Escherichia coli and Staphylococcus aureus as the chitosan fiber and could be recommended as the alternative material for the wound dressing and the food packing.

Barium sulfate/regenerated cellulose composite fiber with X-ray radiation resistance

In this article, submicron barium sulfate particles, as the radiation-resistant component, were incorporated into regenerated cellulose spinning solution. Then a series of X-ray radiation-resistant fibers were fabricated via a primarily industrialized wet-spinning trail, and the resultant fibers were knitted into fabrics by knitting loom. The morphology and structure of the fibers were studied with the aid of scanning electron micrography, Fourier-transform infrared spectroscopy, and X-ray diffraction. The composite fibers exhibited reasonably good properties, which met the criteria of mechanical requirements of commercial textiles—dry breaking strength and elongation (>1.5 cN/dtex and 26%) and wet breaking strength and elongation (>1.4 cN/dtex and 22%) and permanent laundry-resistant abilities even after being washed 20 times. An effective and feasible X-ray radiation-resistant method, the medical digital X-ray photography system, was proposed to evaluate the radiation resistance of the composite fiber and its fabric. The X-ray attenuation ratio of the sample tended to increase with increasing barium sulfate content and finally reached a dose of a 0.1 mmPb lead equivalent. Therefore, these fibers and fabrics can be utilized as the base materials for X-ray radiation-resistant lightweight apparel and detective surgical yarn.

A theoretical analysis of local thermal equilibrium in fibrous materials

The internal heat exchange between each phase and the local thermal equilibrium scenarios in multi-phase fibrous materials are considered in this paper. Based on the two-phase heat transfer model, a criterion is proposed to evaluate the local thermal equilibrium condition, using derived characteristic parameters. Furthermore, the local thermal equilibrium situations in isothermal/adiabatic boundary cases with two different heat sources (constant heat flux and constant temperature) are assessed as special transient cases to test the proposed criterion system, and the influence of such different cases on their local thermal equilibrium status are elucidated. In addition, it is demonstrated that even the convective boundary problems can be generally estimated using this approach. Finally, effects on local thermal equilibrium of the material properties (thermal conductivity, volumetric heat capacity of each phase, sample porosity, and pore hydraulic radius) are investigated, illustrated, and discussed in our study.

Study on Structure and Property of Abelmoschus manihot Fibers

The structure and property of Abelmoschus manihot Manihot fibers were investigated in the present work. Its transverse section was irregular polygon and the single fiber was cylindrical shape. It belonged to cellulose I crystalline structure and its crystallinity was near to cotton and ramie. The breaking strength was lower than ramie fibers and the elongation at break was approximate with these fibers. The moisture regain was better than cotton. It can be dyed easily using high-temperature reactive red dyes and blue dyes. Also, it had the higher thermal stability than cotton.