Key Laboratory of Textile Science & Technology

Science & Technology, China

Key Laboratory of Textile Science & Technology

Science & Technology, China
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Zhang H.,Donghua University | Liu X.,Donghua University | Liu X.,Key Laboratory of Textile Science & Technology
Iranian Polymer Journal (English Edition) | Year: 2017

Photonic crystals play the vital role in structural color appearance, and they can be fabricated on polymer substrates. In this paper, monodispersed SiO2 microspheres with the average diameter ranging from 150 to 300 nm were prepared by classical Stöber method. The spherical size of SiO2 microspheres was regulated by controlling concentrations of ammonia. The tunable structural colors could be changed by modulating the diameters of SiO2 microspheres or viewing angles, which adhered to the law of the Bragg diffraction. As a kind of polymer fabric, the polyester fabrics, smoother than natural fiber fabrics, exhibited bright structural colors from the well-ordered photonic crystal microstructure by vertical deposition self-assembly of SiO2 photonic crystals. Moreover, the result indicated that the difference of fabric-woven structure could affect the lightness of structure color, and the lightness on satin fabric was duller than that of plain fabric. Besides, we have also discussed the influence of fabric structure on the lightness of structure color using the theory of thin film interference. It is believed that the structural color could provide a new strategy for related polymer product coloration without chemical dyes and pigments, and has a potential to reduce the pollution in related polymer materials dyeing and printing processes. © 2017, Iran Polymer and Petrochemical Institute.

Wang X.,Donghua University | Zhao T.,Donghua University | Zhao T.,Key Laboratory of Textile Science & Technology
Textile Research Journal | Year: 2017

Shell formation process is a very vital step in the fabrication of melamine-formaldehyde microencapsulated phase change materials (microPCMs). In this research, the effects of parameters in this process, including system pH value, initial temperature and dropping rate of the prepolymer, were studied systematically to prepare microPCMs with potential application in thermo-regulated textiles. The various properties of obtained microcapsules were investigated by scanning electron microscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Revised encapsulation efficiency (RE) was calculated with a new method based on the results of DSC and TGA, and was used to characterize the encapsulation efficiency of the microPCMs. The experimental results indicated moderate pH, such as 4.6, benefited the formation of regular spherical capsules with high encapsulation efficiency. The products prepared at low pH were almost irregular aggregates, while the microcapsules formed at high pH were easily damaged. It was found that the microcapsules synthesized at a lower initial temperature, such as 40℃, presented poor appearance and low encapsulation efficiency. The suitable initial temperature for shell formation was about 75℃. With the decrease of the dropping rate, the surface morphology of microPCMs showed obvious improvement, while the increment speed of RE was slow. The medium dropping speed could be selected to ensure the encapsulation efficiency as well as the productivity in this experiment. It was also found that RE could reflect the effects of these parameters more accurately in comparison with the conventional apparent encapsulation efficiency (AE). © 2016, © The Author(s) 2016.

Wang Z.,Donghua University | Wang Z.,Key Laboratory of Textile Science & Technology | Wang W.,Donghua University | Wang W.,Key Laboratory of Textile Science & Technology | And 4 more authors.
Applied Surface Science | Year: 2017

Flexible conductive circuits on PET fabrics were fabricated by a simple approach. Firstly, well dispersed nano-silver colloids with average size of 87 nm were synthesized with poly (vinyl pyrrolidone). Then, by adding polyurethane and thickening agent into these colloids, Ag NP-based ink was produced and printed on PET fabrics by screen printing. Conductive patterns were achieved through the swelling process of polyurethane and the decrease of contact resistance between nano-silver particles when immersed in dichloromethane (DCM) and diallyldimethylammonium chloride (DMDAAC) mixed solution. After it was dried at 40 °C,the surface resistivity was about 0.197 Ω cm with width 1.9 mm, and thickness 20 μm. Moreover, the effects of different DCM contents on the conductivity and the film forming ability have been investigated. We believe these foundings will provide some important analysis for printing flexible conductive circuits on textiles. © 2016 Elsevier B.V.

Ou K.,Donghua University | Dong X.,Donghua University | Qin C.,Donghua University | Ji X.,Donghua University | And 2 more authors.
Materials Science and Engineering C | Year: 2017

It is well known that preparation method of hydrogels has a significant effect on their properties. In this paper, freeze-thawing and anneal-swelling were applied to prepare poly(vinyl alcohol)/polyacrylamide (PVA/PAM) double-network hydrogels with covalently and physically cross-linked networks. The properties of these hydrogels were investigated and compared to control hydrogels. Results indicated that hydrogels fabricated by freeze-thawing show larger pores size and higher swelling capacity than those made by anneal-swelling and control hydrogels. Hydrogels prepared by anneal-swelling exhibit higher mechanical strength, energy dissipation, fracture energy, gel fraction and crystallinity than those made by freeze-thawing and control hydrogels. Physical cross-linking plays a key role in formation of physical-chemical double-network. The toughening mechanism of double-network hydrogel is related to their chain-fracture behavior and elasticity. The results also indicated that appropriate methods can endow hydrogels with specific microstructures and properties which would broaden current hydrogels research and applications in biomedical fields. © 2017 Elsevier B.V.

Zhi C.,CSIRO | Zhi C.,Donghua University | Zhi C.,Key Laboratory of Textile Science & Technology | Long H.,Donghua University | And 2 more authors.
Composites Part A: Applied Science and Manufacturing | Year: 2017

The microbond test commonly used to determine the interfacial shear strength (IFSS) of fiber-reinforced composites involves a number of experiment parameters that are not standardized in practice. This investigation is aimed to quantify and explain the influences of these parameters on the test results. We first validated the force-displacement curves and IFSS results of finite element simulated model pullout tests with that from experiments conducted at equivalent conditions. The von Mises and contact friction stress distributions from the simulation models were used to explain the influences of experimental parameters on IFSS from microbond test. The study shows that fiber diameter has the largest effect on IFSS. Bead size and blade position also have significant influences on the IFSS results from microbond tests. These testing parameters should be kept as close to constants as possible when conducting comparative microbond tests. © 2017

Zhang S.,Key Laboratory of Textile Science Technology | Li F.A.-X.,Donghua University | Yu J.-Y.,Donghua University
Cellulose Chemistry and Technology | Year: 2011

The coagulation properties of cellulose-NaOH/thiourea/urea/H 2O solutions under various coagulation conditions have been investigated, to determine the kinetics of this special coagulation process (known as including diffusion on the contact surfaces of the polymer solution with the precipitant and the chemical reaction between acid and alkali). The observation was made that, at the beginning of the coagulation process, thickness of the coagulated layer, ξ(t), is proportional to the square root of time, √ t, which agrees with Fick's law. By building a coagulation model, the influence of precipitant composition and concentration, of coagulation time, bath temperature and cellulose concentration on the coagulation rate has been demonstrated. The process of cellulose shaping from NaOH/thiourea/urea/H 2O solutions can be characterized by examining the thickness and surface morphology of the coagulated layer, which is a reliable and direct method for understanding and controlling the cellulose regeneration behavior. It was found out that the coagulation rate enhanced with the increase in coagulation temperature, and decreased with increasing cellulose concentration. The activation energy of coagulation was calculated to be of 10.808 KJ/mol. The kinetics of diffusion-controlled chemical reactions has been viewed as the mechanism of coagulation.

Zhou D.,Donghua University | Zhu Z.,Donghua University | Zhu Z.,Key Laboratory of Textile Science & Technology | Liu B.,Donghua University | Liu B.,Key Laboratory of Textile Science & Technology
Materials Letters | Year: 2016

A novel reduced graphene oxide (RGO)/BiVO4/SiO2 composites with high-efficiency visible-light photocatalytic activity were synthesized by a simple one-step solvothermal method at 180 °C for 4 h. The as-prepared RGO/BiVO4/SiO2 hybrid material was characterized by X-ray powder diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectrum (UV–vis DRS), respectively. The photocatalytic activity of samples was evaluated by the degradation behaviors of C.I. Reactive Blue 19 in aqueous solution under visible light irradiation at room temperature, which is much higher than that of the pure semiconductor materials BiVO4 and hybrid material BiVO4/SiO2. © 2016 Elsevier B.V.

Wang C.-E.,Donghua University | Wang C.-E.,Key Laboratory of Textile Science & Technology | Zhang P.-H.,Donghua University | Zhang P.-H.,Key Laboratory of Textile Science & Technology
Autex Research Journal | Year: 2016

Biodegradable intravascular stent has attracted more and more focus in recent years as an effective solution for angiostenosis. Ideal stents were expected to exhibit sufficient radial force to support the vascular wall, while suitable flexibility for the angioplasty. After vascular remodeling, stents should be degraded into small molecular and be eliminated from human body, causing no potential risk. In this paper, poly-p-dioxanone (PDO) monofilament was braided into net structure with four different braiding density, two of which exhibited sufficient radial force larger than 30 kPa, and three of which showed the bending rigidity within 11.7-88.1 N•mm2. The degradation behaviors of monofilaments and stents have been observed for 16 weeks. The findings obtained indicate that degradation first occurred in morphology region, which induced temporary increase of crystallinity, monofilament bending rigidity and stent mechanical properties. During this period, monofilament tends to be hard and brittle and lost its tensile properties. Then the crystalline region was degraded and stent mechanical properties decreased. All the results reveal that the PDO intravascular stents with braided structure were able to afford at least 10 weeks of sufficient support to the vascular wall. © AUTEX.

Lv T.-J.,Donghua University | Lv T.-J.,Key Laboratory of Textile Science & Technology | Long H.-R.,Donghua University | Long H.-R.,Key Laboratory of Textile Science & Technology
Textile Research Journal | Year: 2015

In this paper, based on Hessian invariant moments, a new approach for classification of fancy weft knitted stitch was proposed. The speeded up robust features (SURF) algorithm was used to identify fancy weft knitted samples including cable stitch and tuck stitch. Weft knitted stitch images generally contain many repeated features, wrong matches are easily encountered when the SURF algorithm is applied to match images. To resolve this problem, the inflection point of misjudgment was found out. The general regularity of faults and the key threshold were concluded by analyzing a number of classification experiments. The results show that wrong matches can be removed by locking the inflection point and feature matching of fancy weft knitted stitch is proved to be feasible for assigning an unknown image to one of a set of known texture classes. © The Author(s) 2014 Reprints and permissions:

Han W.,Jiaxing University | Wang X.,Donghua University | Wang X.,Key Laboratory of Textile Science & Technology
Fibers and Polymers | Year: 2016

The characteristics of molten polymer plays a major role in fiber formation in the melt blowing (MB) process. In this paper, the Maxwell model and two kinds of the standard linear solid (SLS) models in the bead-viscoelastic element model are proposed for melt blown fiber formation simulation. The fiber diameter, velocity and stress are studied with these different constitutive equations of polymer. The trajectory path of fiber whipping is obtained using numerical simulation and compares with the actual fiber motion which is captured with a high-speed camera. The results present that the Standard Linear Solid Model (SLS) is better than Maxwell model to predict the melt blown fiber’s characteristics under the same air drawing conditions, including fiber diameter, velocity and stress. The whipping motion of the fiber also can be well expressed by SLS constitutive model. The mathematical model with SLS model provides a clear understanding on the mechanism of the formation of microfibers during melt blowing. © 2016, The Korean Fiber Society and Springer Science+Business Media Dordrecht.

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