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To achieve a better balance between the refractive index and Abbe number, the thiol-functionalized polyhedral oligomeric silsesquioxane (POSS–SH) was incorporated as both nanoreinforcement and cros...

As a natural ore, Taichi stone brings potential market value and social value due to its health-care functions, such as releasing far-infrared and anti-ultraviolet (anti-UV) and anti-bacterial functions. In this study, Tachi masterbatch (containing 10% Tachi nanoparticles)/polyester (PET) functional composite fiber was prepared by electro-spinning. To study the effect of nanoparticle content on the composite fibers, five spinning solutions with different nanoparticle contents were mixed and electrospun. The spun fibers were then characterized by using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and far-infrared and UV testing devices, respectively. The result shows that when the Taichi nanoparticle content is 3%, the composite fiber membranes will have a better dispersion, the fiber is more uniform, and smaller fiber diameter can be obtained. Compared with the pure PET fiber, the composite fibers have an improved far-infrared radiation performance and anti-UV performance. The highest nanoparticle content of 7% composite fiber gives the best far-infrared radiation and anti-UV performance. The newly developed Taichi masterbatch/PET functional composite fibers have potential application for the development of multi-functional textiles and apparels in the future.

In this work, the effect of modified graphene oxide and polytetrafluoroethylene (PTFE) on the tribological and anticorrosion properties of waterborne polyurethane (WPU) was studied. The modified graphene oxide (MGO) was obtained by the surface functionalization modification of graphene oxide (GO) with isophorone diisocyanate (IPDI), and MGO/WPU composite coating and MGO-PTFE/WPU composite coating with different mass fractions of MGO were prepared. The tribological and electrochemical experiment results demonstrated that the tribological properties of the coating and the corrosion resistance of the worn coating were effectively enhanced under the synergistic effect of MGO and PTFE. Finally, a mechanism was proposed to explain the improvement in anticorrosion performance of the worn coating.

The surface modified hydrophilic zinc sulfide nano powder was prepared by hydrothermal method, and the corresponding zinc sulfide/polyurethane organic-inorganic composite transparent coating via in-situ polymerization. The structure of ZnS Nanoparticles and organic-inorganic composite coating were characterized by Infrared Spectroscopy, X-Ray Diffraction, Laser Particle Size Analyzer and Scanning Electron Microscopy. The optical properties were measured by Ultraviolet-Visible spectrophotometer and ellipsometry. The results show that the monodisperse hydrophilic nano zinc sulfide powder with a particle size of about 70 nm can be obtained by thioglycolic acid (TGA) modification, which has good compatibility with waterborne polyurethane. Nano zinc sulfide increased the refractive index of the coating significantly and the refractive index of the coatings could be controlled in the region of 1.46–1.71 organic-inorganic composite coating by adding ZnS. When the amount of nano ZnS added was 30%, the refractive index of the hybrid coating can reach 1.71, and the transmittance was more than 90%. The cured coatings were smooth and no agglomeration between nano ZnS particles could be found. After application on the surfaces of resin lens, the coatings presented better impact resistance, which indicated that the coating has application prospects in the field of fine processing of lens’ surfaces.

The homogeneous SiO2-TiO2 composite sols were prepared by organic-inorganic synchronous polymerization with titanium isopropoxide and tetrabutyl silicate as precursor. The organic-inorganic composite hard coating with Si-O-Ti as the framework was prepared by adding compound crosslinkers (up-401) and 3-Methacryloxypropyltrimethoxysilane (KH-560). The structure of the coating and the hardened film were characterized by infrared spectrum, scanning electron microscopy, atomic force microscopy, particle size analyzer and thermogravimetry. The refractive index, transmittance and hardness of the hardened film were measured by ellipsometry, UV-Vis spectrophotometer and hardness tester. By adjusting the ratio of Si/Ti and optimizing the reaction conditions, the hardness of the hardened film could reach 6H, and the refractive index could be adjusted from 1.55 to 1.76. At the same time, the application of hard coatings on the surface of optical lens were studied.

A polythiourethane thermoset system based on a diisocyanate and a trithiol was investigated by dynamic rheological measurements. Strain sweep was performed to determine the linear elastic region of the thermosetting system. The changes of characteristic parameters including elastic modulus, viscous modulus, and complex viscosity were recorded in a heating ramp to trace the cross-linking and structural evolution during the curing process. Time sweep at constant temperatures was also performed to explore possible curing strategy at reduced temperatures. In addition, frequency sweep was conducted to confirm the temperature- and time-dependent viscoelastic properties of the thermoset system during the curing process. Both continuous heating and isothermal aging gave rise to solidification of the polythiourethane with similar critical structure, as evidenced by the critical values of relaxation exponent. A combination of isothermal aging and heating is expected to be a facile strategy for fabricating thermoset polythiourethane polymers at lower temperature or/and reduced curing time. A kinetic study was done to confirm the gelation characteristics of the polythiourethane system, and the activation energy was also calculated.

The electrospinning of polyacrylonitrile (PAN) fibers from strain-hardening PAN solutions was studied. The strain-hardening PAN electrospinning solutions were prepared by adding ultrahigh-molecular-weight PAN (UHMWPAN) into medium-molecular-weight PAN (MMWPAN) solutions. The strain-hardening behavior of the solutions was evidenced by the CaBER extensional rheological tests. In electrospinning of PAN nanofibers, the solutions containing UHMWPAN were found to be stable when large electric field intensity was applied at a constant source-target distance, different from the case that a solution without UHMWPAN was used. PAN nanofibers with smaller diameter (270 nm compared with 496 nm for the nanofibers containing no UHMWPAN) could be electrospun from the strain-hardening solutions at larger electric field intensity and no beaded fibers were observed. The results of X-ray diffraction (XRD) and mechanical tests showed that the crystallinity, crystal orientation and mechanical performance of electrospun PAN nanofibers were improved with the increase of electric field intensity.

The spinnability in pre-gelled gel spinning of polyacrylonitrile (PAN) precursor fibers was investigated. The spinning solutions were aged at 25 °C for different times prior to fiber spinning. The pre-gelled spinning solution aged for 2.5 h was much more strain hardening than the ungelled one, which can increase the spinnability of the solution. The maximum take-up velocity of the first winding roller V 1m, which reflects the spinnability of the spinning solutions, was found to be largest when the aging time was 1.5 h. The spinnability increased with the increase of the air gap length and the lengthdiameter ratio L/D of the spinnerette. Once the L/D increased beyond 15, the spinnability hardly changed. The fibers spun from the spinning solution aged for 1.5 h had the best mechanical properties and favorable structure, showing that good spinnability favors the performance increase of resultant PAN precursor fibers.

Bovine serum albumin/poly(acrylic acid), BSA/PAA, nano-scaled particles were produced by noncovalent bonds induced self-assembly method at acid pH area. Proper conditions during preparation process, such as pH value, BSA/PAA weight ratio(WR), PAA molecular weight, were researched by studying the hydrodynamic diameter, polydispersity index, and ζ potential of the nanoparticles. Complex formation between BSA and PAA was studied by FT-IR, AFM, and TEM. BSA chains are supposed to be partly trapped in the nanoparticles core after interaction with PAA because of the electrostatic attractions and hydrogen bonds interactions between BSA and PAA, while the rest of the BSA chains should form the shell of the nanoparticles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

The thermal-induced gel spinning of polyacrylonitrile/dimethyl sulfoxide/water solutions were performed. The structure and performance of the PAN precursor fibers were characterized by mechanical properties testing, swelling capacity testing, scanning electron microscopy, and X-ray diffraction. The effects of the water content, polymer concentration, coagulation bath temperature, and draw ratio on the cross-sectional morphology, structure, and tensile properties are reported. The results show that 2% water content is optimal due to dispersed small pores found in the fibers' cross section. With the coagulating bath temperature decreased, the large pores in fibers also decreased. Large pores almost disappeared up to −9°C. The mechanical properties of the PAN fibers increased with the enhancement of PAN concentration, while the decrease of the coagulating bath temperature or water content would induce the improvement of the fibers' mechanical properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

The constant rotational rheological behaviors of PAN/DMSO solutions with two kinds of nonsolvent (water and ethanol) have been investigated, respectively, using a cone-plate rheometer. From viscosity measurements, the flow behavior was described within the shear rate range 0.1–1000 s−1. The PAN solutions show shear thinning at high shear rates. The viscosities of the solutions decreased with the rising of the temperature at low shear rate. H2O content has great influence on the viscosity of the solutions, depending on the hydration of H2O and PAN or desolvent effect, according to different H2O content. The role of ethanol compared with H2O was also researched and higher viscosity was found. Non-Newtonian index, structural viscosity index Δη, and flow activation energy of the PAN/DMSO/H2O systems were also studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

The spinnability and polydispersity of polyacrylonitrile/dimethyl sulfoxide (PAN/DMSO)/H2O spinning solutions with conventional PAN molecular weight and comparative high PAN concentration have been investigated using a cone-plate rhe- ometer. It is observed from the measurements that, the viscosities of the solutions decreased with the rising of shear rate, and then stabilized to almost the same value, regardless of the PAN concentration. The chain orientation in the fiber formed under constant shear rate cannot be changed considerably even after long relaxation of more than 900s. For dynamic experiments, a steady increase of both G 0 and G 00 with escalating oscillation frequency was seen for all samples. Higher viscous-elastic mod- ulus at higher H2O content was found, too. It is also concluded from the log G 0 � log G 00 plot and the gel point that the PAN/DMSO/H2O system with regular PAN molecu- lar weight behaves very close to a mono-disperse system, thus very suitable for gel spinning and for preparation of high performance PAN precursor fiber. V C 2009 Wiley

Natural clay-supported iron oxide was prepared by deposition method, and dried at 120 °C. It was found that under visible light in the presence of H2O2, this catalyst was highly active for degradation of cationic (malachite and fuchsin basic) and anionic dyes (orange II and X3B) in water at pH 6.5, as compared with bare iron oxide or the clay-supported iron oxide sintered at 350 °C. The excellent performance of the catalyst is correlated with its high sorption capacity toward both types of dyes, thus resulting in enhanced dye degradation via a photosensitization pathway. The catalyst was characterized by XRD, nitrogen adsorption, infrared, and UV–visible spectroscopy.

Several studies have shown that addition of NaF into the aqueous dispersion of TiO2 (Degussa P25) can result in significant enhancement in the photocatalytic degradation (PCD) of organic pollutants, ascribed to the enhanced production of free OH radicals in solution as a result of fluoride displacement of surface hydroxyl groups. In this work, we have observed different results of NaF addition for the PCD of phenol over synthetic TiO2 in aqueous suspension under UV light irradiation (λ ≥ 320 nm). Upon the addition of NaF, the rate of phenol PCD was only increased with anatase, but it was decreased with rutile under similar conditions. In the presence of AgNO3, however, the fluoride-induced rate enhancement of phenol PCD could be observed with both anatase and rutile, ascribed to the increased rate of scavenging the conduction band electrons. As the catalyst sintering temperature was increased, the amount of fluoride adsorption on TiO2 was decreased, but the degree of PCD rate enhancement due to NaF additi...

Ultrafine ZnM 2 O 4 (M = Fe, Co, Cr) powders have been successfully fabricated by using a novel polyoxyethylene lauryl ether + n -hexanol/ n -heptance/water (zinc nitrate + ferrum nitrate or cobalt nitrate or chromium nitrate) W/O microemulsion method. The composition and the structure of the powers have been investigated by means of XRD and TEM. The results show the as-received ZnM 2 O 4 have spinel-type structure and the every size of the spherical particles are below 60 nm with good dispersity. The influence of temperature on the sensitivities, selectivities, and the response and recovery characteristics are tested. The results of gas sensing measurement show the ZnFe 2 O 4 sensors have a high sensitivity, excellent selectivity and quick response behavior to Cl 2 gas compared with ZnCo 2 O 4 and ZnCr 2 O 4 sensors. The response of ZnFe 2 O 4 to Cl 2 gas shows the resistance increase that indicates an n-type semiconductor behavior while ZnCo 2 O 4 and ZnCr 2 O 4 have p-type semiconductor characteristic.

Stable water-dispersible silver nanoparticles with a narrow size distribution are obtained by light-assisted spontaneous reduction of silver nitrate with gelatin, which acts as both the reducing and the stabilizing agents, in water. The formation mechanism of the silver nanoparticles involves an in-situ conversion of Ag(+)-gelatin aggregates to gelatin-stabilized silver nanoparticles via a Ag(+)-mediated oxidation of primary amine groups of the gelatin to carboxylic acid groups. The resultant silver nanoparticles are well within the quantum size domain (10 nm). In addition, the nanoparticles are stable in aqueous solutions and can be separated easily by simple pH adjustment.

The effect of sintering temperature (150-900 degrees C) on the photocatalytic activities of ferric oxide and silica-supported ferric oxide for Orange II degradation in water has been examined under UV light irradiation in the absence and presence of H2O2. The solids are characterized by X-ray powder diffraction, nitrogen adsorption, UV/vis diffuse reflectance spectroscopy, FTIR, and Raman spectroscopy. It was observed that the amount of dye adsorbed and the rate of dye photodegradation on these catalysts were a function of sintering temperature and the suspension pH. Evidence appears to correlate with the crystallinity, particle size, and flat-band potential of hematite, in agreement with the model of semiconductor photocatalysis. The recycling experiment showed that bare hematite was relatively stable, whereas silica-supported ferric oxide experienced a progressive degradation, due to preferential deposition of the dissolved ferric species onto silica, possibly with formation of amorphous and low photoactive ferric (hydr)oxide.

PAA/gelatin nanoparticles, with interpolymer complexes of gelatin and polyacrylic acid (PAA) as the cores and gelatin as the shells, were prepared via facile polymerization of AA on gelatin template. The morphology change of the nanoparticles during the reaction was traced by a combined use of dynamic light scattering (DLS) and atomic force microscopy (AFM) techniques, which revealed a discrepancy among the structure of the nanoparticles formed at different stages of the reaction: as the reaction proceeds, nanoparticles with larger compact cores and thinner shells are produced. The resultant nanoparticles are multi-responsive. Especially, they exhibit a significant temperature-dependent size change: upon raising the temperature from 25 degrees C, the nanoparticle size decreases monotonically until reaching equilibrium at about 40 degrees C. This temperature-dependence of the nanoparticle size was found to be reversible provided the nanoparticle solution was cooled at a low temperature (4 degrees C). The thermo-sensitivity of the nanoparticles is attributed to the thermo-induced sol-gel transition of the gelatin shells. In addition, the nanoparticles were further converted to hollow spheres via successive locking the shell structure by the reaction of gelatin with cross-linker glutaraldehyde, and cavitation of the cross-linked nanoparticles by switching the medium from acidic to neutral. The cavitation process was monitored by DLS, which indicated a mass decrease and size shrinkage. AFM and transmission electron microscopy (TEM) were used to trace the morphology change of the nanoparticles during the cavitation. The hollow structure was confirmed by TEM observation.

Photoinduced organic oxidation with iron (hydr)oxides in aqueous suspension has been argued with respect to two principal mechanisms: (a) photoinduced ligand-to-metal charge transfer within a surface complex and (b) semiconductor photocatalysis. In this work, the photodegradation of azo dye orange II with UV light (lambdaor = 320 nm) in the aerated aqueous suspensions of haematite, maghemite, magnetite, goethite, lepidocrocite, and feroxyhite at an initial pH of 6.5 has been examined. The results showed that (1) all of the catalysts were effective at initiating dye photodegradation but the iron oxides appeared to be more active than the iron hydroxides; (2) the photodissolution of different iron phases and the dye photolysis in the dissolved iron solutions were very slow; (3) the initial rate of dye loss was proportional to the initial amount of adsorption, implying dye photodegradation on the catalyst surface; and (4) upon addition of H2O2, AgNO3, and NaF to the suspension, the rate of dye photodegradation was significantly enhanced with all the catalysts. In the presence of H2O2, less than 50% of the total rate enhancement was ascribed to the photo-Fenton reaction in solution and the dark Fenton reactions in solution and on the catalyst. In the presence of AgNO3, about 1 mole of silver particles was produced by consuming 3 moles of the dye substrate. In the presence of NaF, hydroxyl radicals were detected by an ethanol scavenger, whereas such radicals were not found in the absence of NaF. Moreover, under visible-light irradiation (lambdaor = 450 nm), the dye degradation was much slower than that under UV irradiation, but the reaction was also accelerated by the addition of NaF and AgNO3. The results suggest that mechanism b, not mechanism a, is operative for dye photodegradation occurring on the iron (hydr)oxides. A detailed discussion of all possible pathways is given in the text.