STUDY ON PHASE-SEPARATION OF PMMA/SAN BLENDS INDUCED BY GLASS BEADS THROUGH DYNAMIC RHEOLOGICAL MEASUREMENTS

Based on the premise that the addition of glass beads （GB） could hardly influence the linear viscoelasticity in low frequency （ω） region for homogeneous polymer systems, the dynamic rheological behaviors of unfilled and filled poly（methyl methyacrylate） （PMMA）/poly（styrene-co-acrylonitrile） （SAN） blends were studied in order to explore the effect of GB on the phase-separation of binary polymer matrix. Results show that GB has an induced effect on the phase-separation, which embodies that the phase-separation temperature （Ts） of PMMA/SAN blend filled with GB is lower than that of the unfilled system. The higher content of GB, the higher is the ＂secondary plateau＂ of ω in the terminal region of storage modulus （G＇） versus ω plot. The ＂secondary plateau＂ appearing in the terminal region is attributed to the phase-separation of PMMA/SAN blends and it becomes more fiat for filled polymer blends under the same conditions. However, it is suggested that this kind of ＂induced effect＂ is related to the GB content; the higher content of GB particles might enhance the interaction between the particles and polymer matrix. Moreover, it is found that the addition of GB also has an influence more or less on the morphology and domain size of polymer matrix. It is believed that the plot of dynamic viscosity （η＇） versus the loss viscosity （η＂） is sensitive to examine the effect induced by GB on the phase-separation of binary polymer matrix.

Triaxial test on glass beads simulating coarse-grained soil

It is feasible to study the mechanical characteristics of coarse-grained soil by simulated granular materials such as glass beads.In this paper,3 mm diameter glass beads are used to conduct drained and undrained triaxial tests under different confining pressures to explore their strength,deformation and critical state characteristics.Specifically,the influence of drainage and confining pressure on the stick-slip phenomenon of glass beads is reported.The experimental findings from triaxial tests show that the stress-strain relationship of glass beads softens when the confining pressure is high.Under the undrained condition,the initial modulus increases with the increase in the confining pressure.In contrast,it is not significantly affected by the confining pressure in the drained condition.It is quite evident that the glass beads hardly contract during the shearing process,and their stress path is approximately a segmented straight line.The slope of the critical state line under the undrained condition is greater than that under the drained condition,and the friction angle of the glass beads under the undrained and drained conditions is calculated to be 28.1and 29.5,respectively.The phenomenon of stick-slip has been depicted for the different test conditions,and the stick-slip amplitude linearly increases with the confining pressure,especially in the undrained condition.It is also found that the maximum energy released from the phenomenon of stick-slip increases linearly with the confining pressure.

Effect of Fe_(2)O_(3) on the Formation of Micro Glass Beads under Air Staged Combustion

The effect of Fe_(2)O_(3) on the formation of micro glass beads(MGBs)under air staged combustion was studied.The experimental temperature was 1450℃,and Hegang bituminous coal was used as the experimental object.X⁃ray diffractometer(XRD),ash fusion tester,viscosity formula and scanning electron microscopy(SEM)were used to analyze the fly ash.Nano Measurer 1.2 software was used to measure the diameter of MGBs.The results showed that with the increase of Fe_(2)O_(3) in Hegang coal,the glass phase in fly ash first increased and then decreased.When the amount of Fe_(2)O_(3) was 15%,the content of the glass phase was the highest,which was 51.26%.The ash melting point first decreased and then increased,while the viscosity gradually decreased and the particles gradually became spherical.With the increase of Fe_(2)O_(3),the proportion of MGBs with particle size less than 10μm increased gradually.From the above results,it can be concluded that the addition of Fe_(2)O_(3) is conducive to the formation of MGBs and the reduction of particle size.

Preparation and Properties of Ni-plated Glass Beads/PVC Composite

Ni-plated glass beads（GB） was obtained by electroless plating, based on PVC adhesive, Niplated GB/PVC composite was prepared. Temperature insulation, fi re retardation and microwave absorption properties were tested, the results showed that the nickel coating was compact and continuous, Ni-plated GB/ PVC composite is a kind of excellent temperature insulated, fi re retardate and light-weight material, and especially for microwave absorption well; Refl ectivity was lower than-2 dB in the frequency range of 11-17 GHz.

EFFECT 0F INTERFACIAL ADHESION ON CRYSTALLIZATION AND MECHANICAL PROPERTIES OF POLY (ETHYLENE TEREPHTHALATE)/GLASS BEAD COMPOSITES

The interfacial adhesion between poly (ethylene terephthalate) (PET) and glass beadwas investigated by scanning electron microscope and parallel-plate rheometer. Effect ofinterfacial adhesion on the crystallization and mechenical properties of PET/glass beadcomposites was also studied by differential scanning calorimeter and mechanical testers.The results obtained indicate that the glass bead has a heterogeneous nucleation effecton the PET crystallization. Although better interfacial adhesion is advantageous to theincrease of the tensile strength of the composite, yet it is unfavorable to the crystallizationof PET. It should be pointed out that the crystallization rate of filled PET is always higherthan that of pure PET, regardless of the state of interfacial adhesion.

Study on Surface Modification of Glass Bead by a Block Copolymer Coupling Agent

A tri-block copolymer coupling agent polystyreneblock-poly （n-butyl-acrylate）-block-poly （y-methacryloxypro pylt rimethoxysilane）（PS-b-PnBA-b-PMPS） was synthesized by atom transfer radical polymerization （ATRP）, and its molecular structure was characterized by fourier-transform infrared spectra, hydrogen nuclear magnetic resonance and gel permeation chromatography. The glass bead was treated with the block copolymer coupling agent, and then studied by transmission electron microscopy. The result showed that strong interaction was formed between the block copolymer coupling agent and the surface of glass bead, and then the block of poly（n-butylacrylate） formed a layer of film on the surface.

Photocatalytic degradation of PCP-Na with TiO_2 photocatalysis loaded with platinum

Titanium dioxide(TiO 2) samples of different crystal forms were prepared by hydrolysis tetrabutyl titanate in various water to alkoxide ratios and sintering the hydrolysis product at different temperatures. The photocatalysts coated on hollow glass beads and loaded with platinum varying from 0.2% to 2.4% by weight.The photocatalytic degradation rate of sodium pentachlorophenolate (PCP-Na) depends on the preparing conditions such as: sintering temperatures, water to alkoxide ratios( R ), platinum content and the size. The proper conditions of preparation photocatalysts are as follows: the ratio of TiO 2 : sodium silicate : hollow glass beads : platinum is 10:5:20:0.15(w/w), R is 100, sintering temperature is 650℃, and the size of hollow glass is 0.5-1 mm. Under these conditions, the ratio between acatase and rutile of the photocatalyst is 2:1, and the photocatalytic activity is high.

The detection of tetrahydrofuran hydrate formation and saturation using magnetic resonance imaging technique

Tetrahydrofuran（THF） hydrate was formed in bulk as well as in glass beads pack with a mean diameter of 3.0 mm by controlling the temperature under ambient pressure.Images of THF hydrate formation procedure were obtained using the magnetic resonance imaging（MRI） technique.The experiment results showed that MRI is an effective method for the detection of hydrate formation.Saturation of hydrate formed both in bulk and glass beads can be confirmed by intensity integration of MRI images.

High-efficiency removal of NO_x using dielectric barrier discharge nonthermal plasma with water as an outer electrode

With the rapid increase in the number of cars and the development of industry, nitrogen oxide （NOx） emissions have become a serious and pressing problem. This work reports on the development of a water-cooled dielectric barrier discharge reactor for gaseous NOx removal at low temperature. The characteristics of the reactor are evaluated with and without packing of the reaction tube with 2 mm diameter dielectric beads composed of glass, ZnO, MnO2, ZrO2, or Fe203. It is found that the use of a water-cooled tube reduces the temperature, which stabilizes the reaction, and provides a much greater NO conversion efficiency （28.8%） than that obtained using quartz tube （14.1%） at a frequency of 8 kHz with an input voltage of 6.8 kV. Furthermore, under equivalent conditions, packing the reactor tube with glass beads greatly increases the NO conversion efficiency to 95.85%. This is because the dielectric beads alter the distribution of the electric field due to the influence of polarization at the glass bead surfaces, which ultimately enhances the plasma discharge intensity. The presence of the dielectric beads increases the gas residence time within the reactor. Experimental verification and a theoretical basis are provided for the industrial application of the proposed plasma NO removal process employing dielectric bead packing.

Effects of Fillers on the Damping Property of Ethylene Vinyl-Acetate/Polylactic Acid Blends

New and high performance damping materials from ethylene vinyl-acetate copolymer (VA content over 40%, shorted as EVM) and polylactic acid (PLA) blends were prepared with dicumyl peroxide (DCP) as the curing agent and triallyl isocyanurate (TAIC) as the curing coagent. The effects of silica, mesoporous silica and glass beads on the damping of the EVM/PLA blends were examined using a dynamic mechanical analyzer (DMA). The microstructures of the silica, mesoporous silica and glass beads were observed by transmission electron microscope (TEM). The dispersion of the fillers in the matrix was studied using a Rubber Process Analyzer (RPA). The results showed that silica filled blend had an effective damping temperature range (EDTR, tan δ> 0.3) of 81℃, while the mesoporous silica/silica and glass beads/silica filled blends had EDTR of 86℃ and 85℃, respectively. Mixtures of mesoporous silica and silica as well as glass beads and silica exhibited a more improved dispersion in the blends than silica alone. Blends filled with mesoporous silica and glass beads retained good mechanical properties as well as improved damping performance.

Effects of Shear Fracture on In-depth Profile Modification of Weak Gels

Two sand packs were filled with fine glass beads and quartz sand respectively. The characteristics of crosslinked polymer flowing through the sand packs as well as the influence of shear fracture of porous media on the indepth profile modification of the weak gel generated from the crosslinked polymer were investigated. The results indicated that under the dynamic condition crosslinking reaction happened in both sand packs, and the weak gels in these two cases became small gel particles after water flooding. The differences were： the dynamic gelation time in the quartz sand pack was longer than that in the glass bead pack. Residual resistance factor （FRR） caused by the weak gel in the quartz sand pack was smaller than that in the glass bead pack. The weak gel became gel particles after being scoured by subsequent flood water. A weak gel with uniform apparent viscosity and sealing characteristics was generated in every part of the glass bead pack, which could not only move deeply into the sand pack but also seal the high capacity channels again when it reached the deep part. The weak gel performed in-depth profile modification in the glass bead pack, while in the quartz sand pack, the weak gel was concentrated with 100 cm from the entrance of the sand pack. When propelled by the subsequent flood water, the weak gel could move towards the deep part of the sand pack but then became tiny gel particles and could not effectively seal the high capacity channels there. The in-depth profile modification of the weak gel was very weak in the quartz sand pack. It was the shear fracture of porous media that mainly affected the properties and weakened the in-depth profile modification of the weak gel.

Microplastic in an Arid Region: Identification, Quantification and Characterization on and Alongside Roads in Al Ain, Abu Dhabi, United Arab Emirates

Microplastic content was analyzed in road dust, soils alongside roads and stormwater run-offs in Al Ain City, Abu Dhabi. Apart from tire wear material, fibers and degradation products of meso- and macroplastics such as plastic bags and plastic bottle tops were found to be the most dominant plastic microparticles. Speed bumps and artificial turf/lawns were also evaluated as potential sources of microplastics on and alongside roads. It was found that in arid regions Aeolian transport of microplastics may be more important than transport by water.

撞击过程对月表氧逸度的改造:来自嫦娥五号月壤中撞击玻璃珠的启示

Lunar materials are overall more reducing compared with their terrestrial counterparts,but the mechanism remains to be elucidated.In this study,we present a possible explanation for the changes in redox state of the lunar regolith caused by impact events,based on our investigations of the impact glass beads from Chang’e-5 mission.These glass beads contain iron metal grains and show concentration gradients of FeO and K_(2)O(with or without Na_(2)O)from their rims to centers.The compositional profiles exhibit errorfunction-like shapes,which indicates a diffusion-limited mechanism.Our numerical modeling results suggest that the iron metal grains on the surface of the glass beads were generated through the reduction of FeO by elemental K and(or)Na produced during the impact events.Meanwhile,the iron metal grains inside the bead may have formed due to oxygen diffusion driven by redox potential gradients.Furthermore,our study suggests that impact processes intensify the local reducing conditions,as evidenced by the presence of calcium sulfide particles within troilite grains that coexist with iron metal grains on the surface of the glass beads.This study provides insights into the oxygen diffusion kinetics during the formation of iron metal spherules and sheds light on the changes in redox conditions of lunar materials caused by impact events.