Mingwei Tian

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.

Enhanced thermal, UV blocking and dye absorptive properties of chitosan/poly(vinyl alcohol)/graphene oxide fibers

Ductile appearance, remarkable length-diameter ratio, flexible fabrication properties and featured additional functions of functional composite fibers elicit great interest in applications. In this paper, chitosan/poly(vinyl alcohol) composite fibers with different graphene oxide additive (1-7 wt.%) were spun via continuous wet-spinning route and the resultant fibers revealed improved thermal, UV blocking and dye absorptive properties. In details, the component of fibers was characterized by SEM, TEM, FTIR, XRD and the results indicated that the graphene oxide dispersed well in chitosan/PVA matrix and the hydrogen bond was occurred between these components. As expected, the highest graphene oxide content case (7 wt.% GO) possessed the extraordinary UV blocking property as its UPF value reached to 500 arising from UPF=8.11 of 0 wt.% GO case. However, the composite fiber with 1 wt.% GO, rather than 7 wt.% GO, expressed the remarkable thermal stability and dye absorptive property, and the dye absorptive property of 1 wt.% GO showed the highest absorptive capacity of 407 mg/g among all the resultant fibers.

Electromagnetic interference shielding cotton fabrics with high electrical conductivity and electrical heating behavior via layer-by-layer self-assembly route

In our paper, multi-functional cotton fabrics with electrical and electromagnetic interference (EMI) shielding properties via layer-by-layer (LbL) electrostatic self-assembly approach were prepared. Chitosan was adopted as a polycation with graphene added by solution mixing, and poly(sodium 4-styrenesulfonate) (PSS) as a polyanion was deposited on cotton fabric substrate followed by the chitosan–graphene layer alternatively. Structural and morphological characterizations of the prepared LbL samples were carried out using SEM, AFM, XPS, and surface potential techniques. As expected, surface potential value exhibited an obvious “odd–even” regular pattern, which results from the alternating deposition of PSS and chitosan–graphene layers. Further, the electrical conductivity of the 10-layer-deposited fabric reached 1.67 × 103 S m−1. The fabric also exhibits ultrastrong electromagnetic interference (EMI) shielding ability with a maximum SE value of 30.04 dB. The LbL fabric also possesses excellent electrical heating behaviors. The temperature of the resultant fabric would monotonically rise to the steady-state maximum value (ΔTmax) of 134 °C within 8 min when 7 V voltage was applied, and exhibit excellent stability and recyclability. In addition, various performances remained almost unchanged after 10 consecutive washing treatments. The modified cotton fabric with lightweight, flexible and high-performance EMI shielding properties could be applied in personal protective garments and industrial textiles.

Robust ultraviolet shielding and enhanced mechanical properties of graphene oxide/sodium alginate composite films

To enhance the mechanical performance and ultraviolet shielding property, graphene oxide was incorporated as the functional nanofiller into a sodium alginate matrix to form a composite film via a solvent-casting method. The as-obtained films were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and thermal gravimetric; their mechanical and ultraviolet blocking properties were also systemically evaluated and compared. The results showed that the maximum tensile strength increased to 84 MPa at 6 wt.% graphene oxide loading, nearly 265% greater than that of pure sodium alginate film. The increased tensile strength may have resulted from the existence of hydrogen bonding and high interfacial adhesion between graphene oxide filler and sodium alginate matrix. Furthermore, the sodium alginate/graphene oxide films also demonstrated robust ultraviolet shielding capacity; the corresponding ultraviolet protection factor reached up to 133.61 at 8 wt.% graphene oxide loading.

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.

Polytetrafluoroethylene yarns with thermal stability and fire retardance by scrolled-membrane spinning

Abstract Polytetrafluoroethylene (PTFE) possesses remarkable heat stability, combustibility and low coefficient of friction. In this paper, a kind of new PTFE yarn was spun from PTFE membrane via the method of scrolled-membrane spinning. The morphology of the resultant yarns was characterized by scanning electron microscope. Furthermore, the properties of the yarns were investigated as follow: Single-Yarn Electronic Tensile Strength Tester was used to test the mechanical property, and the dynamic coefficient of friction tester was used to calculate the friction coefficient. And the thermodynamic property of the PTFE yarns was shown by DSC, which the remarkable heat stability demonstrated, containing thermal shrinkage property. Furthermore, the combustibility was investigated and the result showed that the PTFE fiber and Nomex/PTFE fabric possessed desirable thermal properties, where the former was better than the latter.

Fast and simple fabrication of SiO2/poly(vinylidene fluoride) coated cotton fabrics with asymmetric wettability via a facile spray-coating route:

Cotton fabrics with hydrophilic-to-hydrophobic asymmetric surfaces are attractive as potential utilizable structures for functional garments. The spray-coating route could be deemed as a fast and simple way to achieve asymmetric surfaces. In this paper, SiO2 nanoparticles with size ∼ 205 nm were synthesized via the modified sol-gel method, and then modified with poly(vinylidene fluoride) (PVDF) to form a hydrophobic surface. The SiO2 nanoparticles modified with PVDF were uniformly deposited on the outer surface of cotton fabric aided with the robust air flow force from the sprayer. The morphology and chemical structures were characterized by scanning electron microscopy, mapping, atomic force microscopy, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. The results indicated that SiO2 nanoparticles were evenly deposited on the surface of cotton fibers and stable interfacial interaction occurred between SiO2 and PVDF molecular chains. The existence of SiO2 could increase the roughness of the fabric surface, which could enhance the water-repellent property of the coated fabrics. Furthermore, the water-repellent property and thermal insulation properties were evaluated via the water contact angle and thermal conductivity tests, respectively, and the results showed that 20 wt.% SiO2/PVDF fabric achieved a desirable level of contact angle, 136.6°, which was the largest water contact angle among all the samples, and the lowest thermal conductivity of 0.033 W/mK, resulting from the existence of SiO2 nanoparticles. Such a fast and simple spray-coating strategy could be widely introduced into asymmetric fabric modification, and such asymmetric fabrics with reasonable water-repellent and thermal insulating outer surfaces could act as candidates in the field of functional garments.

Effects of irradiation on polyethyleneterephthalate(PET) fibers impregnated with sensitizer

Abstract Polyethylene terephthalate(PET) is difficult to be irradiation cross-linked at low dose for the aromatic groups. In this paper, trimethylolpropane triacrylate (TMPTA) was incorporated in PET fibers to sensitize the cross-linking. Changes in PET fibers subjected to electron beam irradiation at dose up to 200 kGy and dose rate 12 kGy/s were investigated by gel content, scanning electron microscopy, differential scanning calorimetry, X-ray diffraction, thermal gravimetric analysis and X-ray photoelectron spectroscopy. The gel content was 0.14% at dose of 60 kGy and it arrived at the maximum value 0.53% at 100 kGy. Irradiated fibers showed a decrease in the breaking strength and an increase in the elongation at break. The crystal form of PET fibers had not been changed and crystallinity decreased 28% with the increasing dose. The melting temperature shifted from the original 254.28 °C to 253.44 °C. The thermal stability and the amount of non-volatile residue at 800 °C increased at dose of 100 kGy. XPS analysis indicated that the number of C-C band increased to prove the occurring of cross-link. The surface of PET fibers got rougher after irradiation and the anti-dripping property had not been improved effectively for the low degree of cross-linking.

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.