A Versatile Method to Construct Superhydrophobic Fabrics with Good Durability and Self-cleaning Performance

Maiping Yang,WeiQu Liu,Liyan Liang,Chi Jiang,Yankun Xie,Hongyi Shi,Fengyuan Zhang,Ke Pi 한국섬유공학회 2020 Fibers and polymers Vol.21 No.8

In this paper, various fabrics with good self-cleaning performance were prepared via a facile dip-coating method. The fabrics composed with different fibers and woven techniques were firstly immersed in ZnO sol to increase the surfaceroughness, then dip-coated in fluoroalkylsilane (HFT) solution to reduce the surface energy. The coated fabric showedexcellent superhydrophobicity with a water contact angle (WCA) of 157.8 o and water shedding angle (WSA) of 5 o. Themorphologies and chemical compositions of prepared fabrics were observed with SEM, XPS and EDS. The obtained fabrickept stable water-repelling property in acidic and alkaline solutions, solvents and UV irradiation. Benefited from its high antiwaterability and photocatalysis function of ZnO, the coated fabric demonstrated excellent self-cleaning performance. Thisversatile approach of constructing superhydrophobic fabrics is attractive and could be large-scaled employed in industrialproduction process.

Toughening of Epoxy Resin System Using a Novel Dendritic Polysiloxane

Songqi Ma,Weiqu Liu,Chaohui Hu,Zhengfang Wang,Chunyi Tang 한국고분자학회 2010 Macromolecular Research Vol.18 No.4

Dendritic polymers have attracted increasing attention in the field of epoxy resin toughening. This paper is the first report of the use of a novel dendritic polysiloxane (DPSO) bearing high epoxide groups to modify the diglycidyl ether of bisphenol-A (DGEBA). The thermal properties, toughness and morphology of the cured epoxy resins were examined by DSC, TGA, impact testing and SEM. The chemical structure of DPSO was confirmed by FTIR, 29Si NMR and GPC. The Tg increased by approximately 7 oC after introducing the DPSO. The TGA results under N2 and air atmospheres showed that the initial degradation temperature for 5% weight loss (Td 5%), temperature for 50% weight loss (Td 50%) and residual weight percent at 800 oC (R800) all increased after introducing DPSO. Moreover, the addition of 3 phr DPSO100 resulted in a 70.4% increase in impact strength compared to that of the neat epoxy. The morphology of the fracture surfaces shows that the miscibility of polysiloxane with epoxy resin increased with increasing number of epoxy groups in DPSO, and the improved toughness was attributed to the rubber-bridged effect. The high number of epoxy groups in dendritic polysiloxane can react during the curing process,and participate chemically in the crosslinking network. DPSO is expected to improve significantly the toughness and thermal stability of epoxy resin.

Modification of Epoxy Resin with Polyether-grafted-Polysiloxane and Epoxy-Miscible Polysiloxane Particles

Songqi Ma,WeiQu Liu,Dan Yu,ZhengFang Wang 한국고분자학회 2010 Macromolecular Research Vol.18 No.1

Polyether-grafted-polysiloxane (FPMS) and epoxy-miscible polysiloxane particles (EMPP) were prepared to improve the toughness of epoxy resin. The chemical structures of the products were characterized by FTIR,1H NMR, 29Si NMR, and gel permeation chromatography (GPC). The morphology of the EMPP was analyzed by transmission electron microscopy (TEM). The thermal and mechanical properties and morphologies of the polysiloxanes modified epoxy networks were examined by differential scanning calorimetry (DSC), tensile and impact testing, and scanning electron microscopy (SEM). Microspheres were observed in the EMPP modified epoxy network,whereas irregular particles were obtained for the FPMS modified epoxy resin. The FPMS and EMPP effectively improved the tensile and impact strength of the cured epoxies, while the glass transition temperatures (Tgs)were depressed slightly. Moreover, with the same content of modifiers, the EMPP-modified epoxy network exhibited higher impact strength and lower Tgs than the FPMS-modified epoxy network.

Morphologies and Mechanical and Thermal Properties of Highly Epoxidized Polysiloxane Toughened Epoxy Resin Composites

Songqi Ma,Weiqu Liu,Zhengfang Wang,Chaohui Hu,Chunyi Tang 한국고분자학회 2010 Macromolecular Research Vol.18 No.9

A novel highly epoxidized polysiloxane was synthesized to modify the diglycidyl ether of bisphenol-A (DGEBA). The mechanical and thermal properties as well as the morphology of the cured epoxy resins were examined by tensile testing, impact testing, fracture testing, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and environmental scanning electron microscopy (ESEM). The chemical structure of the highly epoxidized polysiloxane (HEPSO) was confirmed by Fourier transform infrared spectroscopy (FTIR), 29Si nuclear magnetic resonance spectroscopy (29Si NMR), and gel permeation chromatography (GPC). The Tg increased by approximately 8 ºC after introducing HEPSO. TGA in air showed that the initial degradation temperature for 5%weight loss (Td 5%), the temperature for 50% weight loss (Td 50%) and the residual weight percent at 800 ºC (R800)were increased after introducing HEPSO. The addition of 4 phr HEPSO2 resulted in the highest increase in tensile strength, impact strength and fracture toughness (KIC). The morphology of the fracture surfaces show that the miscibility of polysiloxane with epoxy resin increased with increasing epoxide group in HEPSO. The high epoxide groups in HEPSO can react during the curing process, and participate chemically in the crosslinking network. HEPSO is expected to improve significantly the toughness and thermal stability of epoxy resin.

Synthesis and Properties of LED-Packaging Epoxy Resin Toughened by a Novel Polysiloxane from Hydrolysis and Condensation

Songqi Ma,Weiqu Liu,Nan Gao,Zhenlong Yan,Yuan Zhao 한국고분자학회 2011 Macromolecular Research Vol.19 No.9

A novel polysiloxane (G_xD_y) containing a large number of epoxide groups and flexible segments was synthesized by hydrolysis and condensation of 3-glycidoxypropyl trimethoxysilane (GPTMS) and dimethyldiethoxylsilane (DMDES) to toughen the 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (ERL-4221). The chemical structures of G_xD_y (molar ratio of GPTMS to DMDES is x/y) were confirmed by Fourier transform infrared spectroscopy (FTIR), ^29Si nuclear magnetic resonance spectroscopy (NMR), and gel permeation chromatography (GPC), and G_4D_6 have the highest degree of branching. The thermal and mechanical properties, morphologies and transmittance of the cured epoxy resins were examined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), tensile testing, fracture testing, SEM, and UV-vis spectroscopy. The T_g of the G_xD_y modified epoxy depends on the structure and addition content of G_xD_y. The TGA results under a N_2 demonstrate that the thermal stability of the epoxy resin was improved by G_xD_y and the Si-(O-)_3 from the GPTMS part forms silica more easily than the Si-(O-)_2 from the DMDES part. The addition of 10 phr G_4D_6 resulted in greatly improved toughness, but maintained the transmittance of the epoxy resin. In addition the morphology of the fracture surfaces showed that G_xD_y can be dispersed homogeneously in the epoxy resin, and the toughening follows the pinning and crack tip bifurcation mechanism. In conclusion, G_xD_y can increase the toughness and thermal properties of the ERL-4221 system simultaneously, and maintain its transmittance. Therefore, G_xD_y can be used as a toughening agent for light emitting diode (LED)-packaging epoxy resins.

Hydrophobic Waterborne Epoxy Coating Modified by Low Concentrations of Fluorinated Reactive Modifier

Hongyi Shi,Weiqu Liu,Maiping Yang,Xinsheng Liu,Yankun Xie,Zhengfang Wang 한국고분자학회 2019 Macromolecular Research Vol.27 No.4

Fluorinated (meth) acrylate oligomer modified epoxy resin (PHFBMA-DGEBA) and polyether-modified epoxy resin (MPEG-DGEBA) were successfully synthesized and used as reactive modifier and emulsifier for epoxy resins, respectively. GPC, FTIR and 1H NMR were employed to verify the synthesis. The influence of both the concentration and the molecular weight of PHFBMA-DGEBA on the properties of waterborne epoxy resin coatings was investigated. Surface energy and surface composition were probed by contact angle measurements and X-ray photoelectron spectroscopy (XPS), which strongly confirmed the enrichment of fluorinate atoms on the surface. The surface energy of waterborne epoxy coating was decreased from 44.46 mN/m to 23.20 mN/m by adding just 0.09 wt% PHFBMADGEBA- 2, indicating its high effectiveness in improving the surface hydrophobicity. Moreover, the physical properties of waterborne epoxy coatings prepared with different concentration and molecular weight of fluorinated reactive modifier, such as water absorption, Shore D hardness, adhesion, thermal properties and optical transmittance, were also analyzed in detail. Taken together, the waterborne epoxy coatings prepared with low concentrations of reactive modifier are economical and have great potential in large scale industry applications.

Identification of S-Nitrosylation of Proteins of Helicobacter pylori in Response to Nitric Oxide Stress

Wei Qu,Yabin Zhou,Yundong Sun,Ming Fang,Han Yu,Wenjuan Li,Zhifang Liu,Jiping Zeng,Chunyan Chen,Chengjiang Gao,Jihui Jia 한국미생물학회 2011 The journal of microbiology Vol.49 No.2

Innate and adaptive immune responses are activated in humans when Helicobacter pylori invades the gastric mucosa. Nitric oxide (NO) and reactive nitrogen species are important immune effectors, which can exert their functions through oxidation and S-nitrosylation of proteins. S-nitrosoglutathione and sodium nitroprusside were used as NO donors and H. pylori cells were incubated with these compounds to analyze the inhibitory effect of NO. The suppressing effect of NO on H. pylori has been shown in vitro. Furthermore,the proteins modified by S-nitrosylation in H. pylori were identified through the biotin switch method in association with matrix-assisted laser desorption ionization/time-of-flight tandem mass spectrometry (MALDITOF-MS/MS). Five S-nitrosylated proteins identified were a chaperone and heat-shock protein (GroEL),alkyl hydroperoxide reductase (TsaA), urease alpha subunit (UreA), HP0721, and HP0129. Importantly,S-nitrosylation of TsaA and UreA were confirmed using purified recombinant proteins. Considering the importance of these enzymes in antioxidant defenses, adherence, and colonization, NO may exert its antibacterial actions by targeting enzymes through S-nitrosylation. Identification of protein S-nitrosylation may contribute to an understanding of the antibacterial actions of NO. Our findings provide an insight into potential targets for the development of novel therapeutic agents against H. pylori infection.