Papers by Author: Yi Ping Qiu

Abstract: Increasing air pollution caused mainly by exhaust emission has become a serious concern for public health. In order to efficiently control the exhaust emission from the origin, hot gas filtration is required in many industries, such as thermal power regeneration, metal refining/recycling, and biomass/coal gasification. This study aimed to develop a hybrid filter composed with ultrafine fibrous polyimide (PI) filtration layers and carbon woven fabric supporting layers for hot gas filtration. Uniform PI ultrafine fibers around 200 nm with small pores about 2.2 μm were electrospun on carbon fabrics supporting layers to serve as the filtration layer. During filtration test, NaCl aerosols (0.3 mm), which mimicked PM 2.5 particles were accumulated on the top of filtration layer and formed dust cake, but limited aerosols were observed on the carbon fabric supporting layers. It was proved that PI fiber mats played the key role in filtration. The filtration efficiency could be maintained above 95% after 9 min and reached 99.4 %. This research proved that the multi-scale polyimide/carbon fibers hybrid filters possessed the potential to serve as filtration media in bag filters for hot gas filtration.

Abstract: The rigid nature of ramie hairiness on fabrics cause severe itching feeling, which limited the application of ramie fabrics requiring for direct contact to skin. Current modification methods for ramie fabrics are ineffective, expensive or harmful to the main body of fabric. In our research, a low temperature softening method for ramie fabrics in NaOH, urea, glycerol, and Na₂B₄O₇ treatment bath was developed and proven to be efficient in lowering the stiffness and scratchiness of ramie fabrics without significant adverse effect on the fabric strength. Since it is possible to reuse the chemical agents, this treatment was relatively cheap and environmentally friendly.

Abstract: Poly (vinylidene fluoride) (PVDF) / poly(methyl methacrylate) (PMMA) composite membrane was produced by the electrospinning technique. Thermal treatment was introduced to improve the mechanical property and dimensional stability. In this paper, the PVDF/PMMA membranes before and after thermal treatment were characterized by Scanning electron microscope (SEM), differential scanning calorimeter (DSC) , pore size and porosity test, electrolyte uptake test and tensile test. The pore size, porosity, electrolyte uptake rate, tensile property, as well as melting temperature and crystallinity changed with the treated temperature. The results show that thermal treatment could notably increase the tensile property of electrospun PVDF/PMMA composite membrane and 160°C is a proper temperature for thermal treating.

Abstract: The poly (vinylidene fluoride)/poly (methyl methacrylate)(PVDF/PMMA) composite fibrous membranes with different blend ratio for use as separator of lithium-ion batteries have been developed by electrospinning technique. The surface morphology and crystal structure of electrospun PVDF/PMMA composite fibrous membranes are characterized using scanning electron microscopy (SEM), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and differential scanning calorimetry (DSC).The results indicated that the addition of PMMA into PVDF increased the fiber diameter, decreased the crystalline of electrospun composite fibrous membranes and the good molecular level interaction between these two polymers were obtained. Meanwhile,electrospun PVDF/PMMA (90/10) composite fibrous membranes exhibited the highest ionic conductivity of 2.54×10^-3S/cm at room temperature with electrochemical stability of up to 5.0V.

Abstract: Effect of functionalized multi-walled carbon nanotubes (MWCNT) on the interfacial properties of ramie fiber/polylactic acid (PLA) matrix was studied. Ramie fibers were respectively covered by the pristine MWCNT, carboxyl functionalized MWCNT and hydroxide functionalized MWCNT through the simple dip coating method. Scanning electron microscopy (SEM) results showed that all kinds of MWCNT were distributed on the fiber surface at random with some aggregations. Compared to the pristine MWCNT coated fibers with a water contact angle of 84.5 degree, the functionalized MWCNT coating made the fiber surface more hydrophobic. Polarization microscopy indicated that the functional MWCNT could provide the nucleation to form the intact crystalline structure of PLA on the fiber surface. Micro-bond tests showed that the coating of MWCNT on the fiber surface had no significant effect on the interfacial shear strength (IFSS).

Abstract: It has long been a problem how to objectively evaluate the wet wearing comfortability of fabrics. In this paper a novel testing method was proposed, and an instrument was designed and made. During the testing process, the fabric specimen first got saturated by “sweat” and adhered on the “skin”, and then it was separated at due rate from the skin and the in time adhesion force-displacement curve was drawn simultaneously. When the fabric was totally separated from the skin, the maximum adhesion force and adhesion work were measured such as to objectively evaluate the adhesion properties of the fabric specimen. Six different kinds of fabrics were selected and tested. The results show that certain kind of fabric performs characteristic adhesion force-displacement curve, which should be explained through fabric materials and structures. Hence this method is effective in objectively reflecting the wet wearing comfortability of fabrics.

Abstract: Inscription-brocade played an important role in the history of textile technology and exerted great influence upon social production of the Han Dynasty in China. Through analyzing the features of the inscription on the brocade and the social reasons for their emergence, we believe there is a close relationship among the inscription and the social custom, psychology and artistic style of the time. In addition, the perfect combination of inscription and patterns on the brocade stood witness to the mighty advance in the silk technology, the weaving machine such as multi-heald and multi-pedal loom, and the technical application for weaving warp-faced patterns.

Abstract: Polylactic Acid (PLA) and raw Wheat Straw (WS) were used to fabricate WS/PLA green composites. By hot-press process, WS/PLA composites with different WS volume fractions (20% and 30%) were obtained. The experimental results showed that when the WS volume fraction was 20%, the composites had a tensile strength of 23.68MPa and modulus of 1.47GPa; bending strength of 64.13MPa and modulus of 1.44GPa. When the WS volume fraction increased to 30%, the tensile strength and modulus enhanced by 45.18% and 35.37% respectively; bending strength and modulus increased by 15.80% and 25.69%. It was indicated that PLA can be successfully reinforced by WS at certain volume fractions.

Abstract: The electrospinning technique was used to produce poly (vinylidene fluoride) (PVDF) membrane. Thermal treatment was introduced to improve the mechanical property and dimensional stability. In this paper, the PVDF membranes before and after thermal treatment were characterized by Scanning electron microscope (SEM), differential scanning calorimeter (DSC) and wide angle X-ray diffraction (WAXD), tensile testing. The crystallinity, tensile property, as well as melting temperature changed with the treated temperature. The results hows that thermal treatment could notably increase the tensile property of electrospun PVDF membrane and 160°C is a proper temperature for thermal treating

Abstract: The electrospinning technique was used to prepare the Polyethylene Terephthalate (PET) mats. The electrospun PET mats with different fiber diameters have many applications such as biotechnological and biomedical, functional coating, lithum-ion membrane and filtering membrane and so on. Several techniques including scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and single fiber electronic tensile strength tester were used to characterize the electrospun PET mats before/after thermal treatment. When choosing the suitable temperature, the thermal treatment could improve the tensile properties without damage the structure of electrospun PET nanofiber mat, if the suitable temperature was been choosed.