Preparation of hydrophilic reactive polyurethane and its application of anti-water erodibility in ecological restoration

2019 ◽  
Vol 39 (8) ◽  
pp. 736-743 ◽  
Author(s):  
Xinshan Rong ◽  
Lu Zhang ◽  
Xiaoying Zhang ◽  
Zhishui Liang ◽  
Jing Wei ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Surface Hardness ◽  
Ethylene Vinyl Acetate ◽  
Sem Images ◽  
Water Contact ◽  
Soil And Water Loss ◽  
New Material ◽  
Micro Morphology ◽  
Soil And Water ◽  
Scanning Electron

Abstract In this work, a novel hydrophilic reactive polyurethane (HRPU) material and HRPU-based composite materials were prepared and used as chemical anti-water erodibility materials for Pisha sandstone. The compressive strength, surface hardness, penetrability and water contact angle were investigated. The results showed that the deformation rate of Pisha sandstone sprayed with HRPU/ethylene-vinyl acetate (EVA) material was approximately 15%, significantly larger than that of other Pisha sandstone samples, while the compressive strength was significantly improved, providing a good penetrability to form a hydrophobic consolidation layer, locking the water in soil. Meanwhile, the micro-morphology of Pisha sandstone was observed by scanning electron microscopy (SEM) images and the water retaining ability of HRPU/EVA material was discussed in detail. The results showed that the water content of Pisha sandstone sprayed with HRPU/EVA material could reach more than 20%, even after 16 h, which presented an excellent water retaining ability. In addition, the anti-water erodibility of Pisha sandstone with HRPU/EVA was improved to prevent soil and water loss, and provide some feasibility for growing plants. Therefore, it could provide a new material and idea to protect the Pisha sandstone area and other erosion areas.

scholarly journals A Sulfur Copolymers (SDIB)/Polybenzoxazines (PBz) Polymer Blend for Electrospinning of Nanofibers

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1526 ◽  
Author(s):  
Ronaldo P. Parreño ◽  
Ying-Ling Liu ◽  
Arnel B. Beltran
Keyword(s):  
Polymer Blend ◽  
Single Phase ◽  
Fiber Diameter ◽  
Electrospinning Process ◽  
Diameter Distribution ◽  
Sem Images ◽  
Water Contact ◽  
Fixed Concentration ◽  
New Material ◽  
Nanofiber Mats

This study demonstrated the processability of sulfur copolymers (SDIB) into polymer blend with polybenzoxazines (PBz) and their compatibility with the electrospinning process. Synthesis of SDIB was conducted via inverse vulcanization using elemental sulfur (S8). Polymer blends produced by simply mixing with varying concentration of SDIB (5 and 10 wt%) and fixed concentration of PBz (10 wt%) exhibited homogeneity and a single-phase structure capable of forming nanofibers. Nanofiber mats were characterized to determine the blending effect on the microstructure and final properties. Fiber diameter increased and exhibited non-uniform, broader fiber diameter distribution with increased SDIB. Microstructures of mats based on SEM images showed the occurrence of partial aggregation and conglutination with each fiber. Incorporation of SDIB were confirmed from EDX which was in agreement with the amount of SDIB relative to the sulfur peak in the spectra. Spectroscopy further confirmed that SDIB did not affect the chemistry of PBz but the presence of special interaction benefited miscibility. Two distinct glass transition temperatures of 97 °C and 280 °C indicated that new material was produced from the blend while the water contact angle of the fibers was reduced from 130° to 82° which became quite hydrophilic. Blending of SDIB with component polymer proved that its processability can be further explored for optimal spinnability of nanofibers for desired applications.

Study on the Polyurethane Concrete for the Rapid Repairment of Highway Pavement

2012 ◽  
Vol 193-194 ◽  
pp. 762-769 ◽  
Author(s):  
Hui Wang ◽  
Hai Xia Liu ◽  
Cai Hong Zhuang
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Compressive Strength ◽  
Good Mechanical Property ◽  
Curing Agent ◽  
Sem Images ◽  
Rapid Repair ◽  
Chinese Standard ◽  
Scanning Electron ◽  
Highway Pavement

Abstract：Polyurethane concrete which applies to the rapid repair highway pavement was systematically researched. Influences on mechanical properties of the polyurethane concrete of cement-dinas and binder-aggregate ratio, curing agent dosage, thinning agent dosage, etc. were analyzed in this paper. Furthermore, the optimal formulation materials were gotten to use in the repairment of used-broken cement blocks in the experiment. Simultaneously, the microstructure of polyurethane concrete and their adhesive situation bewteen waste cement blocks were observed through scanning electron microscope (SEM). The results show that the flexural strength of the specimen for two hours can reach to 6.67 MPa, and the compressive strength can reach to 9.15MPa, which can achieve the rapid pavement repair on highway in two hours, and it is superior to the related Chinese Standard. Besides the SEM images indicate that polyurethane molecular and aggregate are firmly bonded to each other as well as the cementation between polyurethane concrete and concretes, it means that the material has characteristic of rapid repair as well as good mechanical property.

scholarly journals Mechanical Properties and Micro Morphology of Granite Residual Soil-Based Fly Ash Geopolymer

2021 ◽  
Author(s):  
Yue Huang ◽  
Jian Liu ◽  
Yuedong Wu ◽  
Yuanmin Duan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Fine Particles ◽  
Residual Soil ◽  
X Ray Diffraction ◽  
Fine Grained ◽  
Amorphous Aluminosilicate ◽  
Granite Residual Soil ◽  
Micro Morphology ◽  
Scanning Electron

In order to explore the polymerization mechanism of granite residual soil, geopolymer containing fly ash, various particle groups, granite residual soil and their composites were prepared with different materials. Sodium hydroxide and sodium silicate are used as alkali activators. In this paper, the compressive strength of geopolymer was studied. The mineral composition and microstructure were tested and analyzed by X-ray diffraction and scanning electron microscope. The results show that geopolymerization can only occur in fine particles due to the presence of amorphous aluminosilicate in granite residual soil. The zeolite phase transition of low polymer in fine-grained reaction is beneficial to enhance the integrity of the sample and improve its compressive strength. The addition of fly ash can accelerate the geopolymerization rate and improve the strength of fine geopolymer, but it can inhibit the occurrence of zeolite phase transformation.

Study of the Epitaxial Lateral Overgrowth (ELO) Process for GaN on Sapphire Using Scanning Electron Microscopy and Monochromatic Cathodoluminescence

1998 ◽  
Vol 3 ◽  
Author(s):  
Zhonghai Yu ◽  
M.A.L. Johnson ◽  
T. Mcnulty ◽  
J.D. Brown ◽  
J.W. Cook ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Single Crystal ◽  
Strain Field ◽  
Deep Level ◽  
Green Emission ◽  
Epitaxial Lateral Overgrowth ◽  
Sem Images ◽  
Lateral Overgrowth ◽  
New Material ◽  
Scanning Electron

Growth of GaN by MOVPE on mismatched substrates such as sapphire or SiC produces a columnar material consisting of many hexagonal grains ~1 μm across. In contrast, the epitaxial-lateral-overgrowth (ELO) process creates a new material — single-crystal GaN. We have studied the ELO process using GaN/sapphire layers patterned with SiO2 stripes. SEM images show that the (0001) GaN surface remains very flat as the ELO progresses. Cathodoluminescence images at 590 nm reveal spotty yellow-green emission from the columnar GaN as it emerges from the window areas. Very bright 590 nm emission occurs as the ELO process begins. We associate this deep-level cathodoluminescence with the strain field that accompanies the conversion of columnar GaN into single-crystal GaN via the ELO process. As the ELO process continues across the SiO2 stripes, the 590 nm emission disappears and is replaced with pure band edge cathodoluminescence at 365 nm which is maintained until coalescence of adjacent ELO layers occurs near the centers of the SiO2 stripes.

scholarly journals Experimental Design of Solid Particle Wear Behavior of Ni-Based Composite Coatings

2021 ◽  
Vol 5 (5) ◽  
pp. 133
Author(s):  
Pragyan Senapati ◽  
Harekrushna Sutar ◽  
Rabiranjan Murmu ◽  
Shubhra Bajpai
Keyword(s):  
Experimental Design ◽  
Bond Strength ◽  
Wear Behavior ◽  
Composite Coatings ◽  
High Surface ◽  
Surface Hardness ◽  
Properties Of Coatings ◽  
Sem Images ◽  
The Impact ◽  
Scanning Electron

The composition of nickel-based metal matrix NiCrBSi was varied with 5%, 10% and 15% of Al2O3 particles to obtain high wear resistant coatings by means of a high-velocity oxy fuel (HVOF) thermal spraying process. The coating was characterized by optical microscope, scanning electron microscope (SEM) and X-ray diffractometer (XRD). The physical properties of coatings such as porosity, thickness, surface roughness, surface hardness, fracture toughness, bond strength and density were measured and compared. The experimental design of Taguchi L27 orthogonal array was employed to study and compare the effect of parameters such as impingement angle, impact velocity and alumina per cent in the coating on erosion. The coating containing 15 wt.% of Al2O3 and erodent speed of 33 m/s striking at inclination angle of 30° proved to be the best arrangement in preventing volume loss to a minimum of 0.00015 cc due to low-impact energy, high bond strength and high surface hardness. Analysis of variance (ANOVA) supported the assertion that the impact angle (A) of erodent and composition (C) were the factors contributing most to the volumetric loss as indicated by their combined effect A × C leading to the highest combined factor of 7.34. The scanning electron microscopy (SEM) images of the eroded coatings reveal that the mechanisms of erosion were the fracturing of splats, development of craters, micro cutting and ploughing action.

Study on Mechanical and Thermal Properties of Graphite Modified Cement Concrete

2014 ◽  
Vol 599 ◽  
pp. 84-88 ◽  
Author(s):  
Shao Peng Wu ◽  
Peng Wang ◽  
Bo Li ◽  
Ling Pang ◽  
Fei Guo
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Mechanical And Thermal Properties ◽  
Cement Concrete ◽  
Sem Images ◽  
Graphite Content ◽  
Comprehensive Survey ◽  
Flake Structure ◽  
Scanning Electron

The comprehensive survey on the thermal conductive cement concrete consists of graphite is obtained in this paper. The effects of graphite on mechanical properties and thermal properties were investigated to determine the optimum materials design. Additionally, scanning electron microscopy (SEM) was used to elucidate micrographs of the fracture graphite modified cement concrete. Result indicated that graphite could greatly improve the thermal conductivity properties of cement concrete, but degrade the related compressive strength simultaneously. When the graphite content is 15%, the increment of the thermal conductivity was 50% while the reduction of the compressive strength was almost 90%. Furthermore, SEM images illustrated that the reason for the degradation of mechanical strength maybe depend on the flake structure of graphite.

The Effect of Dry Mix Sodium Hydroxide onto Workability and Compressive Strength of Geopolymer Paste

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
A. Z. Mohd Ali ◽  
◽  
N. A. Jalaluddin ◽  
N. Zulkiflee ◽  
◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Alkaline Solution ◽  
High Emission ◽  
New Material ◽  
Curing Regime ◽  
Solid Form ◽  
Geopolymer Paste

The production of ordinary Portland cement (OPC) consumes considerable amount of natural resources, energy and at the same time contribute in high emission of CO2 to the atmosphere. A new material replacing cement as binder called geopolymer is alkali-activated concrete which are made from fly ash, sodium silicate and sodium hydroxide (NaOH). The alkaline solution mixed with fly ash producing alternative binder to OPC binder in concrete named geopolymer paste. In the process, NaOH was fully dissolved in water and cooled to room temperature. This study aims to eliminate this process by using NaOH in solid form together with fly ash before sodium silicate liquid and water poured into the mixture. The amount of NaOH solids were based on 10M concentration. The workability test is in accordance to ASTM C230. Fifty cubic mm of the geopolymer paste were prepared which consists of fly ash to alkaline solution ratio of 1: 0.5 and the curing regime of 80℃ for 24 hours with 100% humidity were implemented. From laboratory test, the workability of dry method geopolymer paste were decreased. The compressive strength of the dry mix of NaOH showed 55% and the workability has dropped to 58.4%, it showed strength reduction compared to the wet mix method.

Effect of preset interfacial ZrB2 particles on the microstructure and properties of C/C-AlSi composites

2021 ◽  
pp. 002199832110046
Author(s):  
Wei Feng ◽  
Chengwei Tang ◽  
Lei Liu ◽  
Jian Chen ◽  
Yang Zhang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Thermal Expansion ◽  
Thermal Shock ◽  
Retention Rate ◽  
Pressure Infiltration ◽  
Micro Scale ◽  
Before And After ◽  
Micro Morphology ◽  
Strength Retention ◽  
Fiber Fabric

ZrB2 particles were preset to the C-AlSi interface to improve oxidation resistance of C/C preform and adjust the microstructure of the interpenetrated C/C-AlSi composite prepared through pressure infiltration of eutectic AlSi into a fiber fabric based porous C/C skeleton. Micro-morphology investigations suggested that the AlSi textures were changed from dendritic to petals-like state, and the nano to micro-scale ZrB2 particles were dispersed into AlSi and affected the distribution of Al and Si nearby carbon. Tests demonstrated that C/C-AlSi have slight lower density and thermal expansion coefficient, and higher original compressive strength, while C/C-ZrB2-AlSi composites presented an outstanding strength retention rate after thermal shock. Fracture and micro-morphology indicated that the influence of the preset ZrB2 to the interface of carbon and alloy greatly affected the generation and propagation of cracks, which determined the diverse compression behaviors of the composites before and after thermal shock.

scholarly journals Microscopy Methods for Biofilm Imaging: Focus on SEM and VP-SEM Pros and Cons

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 51
Author(s):  
Michela Relucenti ◽  
Giuseppe Familiari ◽  
Orlando Donfrancesco ◽  
Maurizio Taurino ◽  
Xiaobo Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ion Beam ◽  
Ruthenium Red ◽  
Variable Pressure ◽  
Sem Images ◽  
Advantages And Disadvantages ◽  
Pros And Cons ◽  
Microscopy Techniques ◽  
Scanning Electron

Several imaging methodologies have been used in biofilm studies, contributing to deepening the knowledge on their structure. This review illustrates the most widely used microscopy techniques in biofilm investigations, focusing on traditional and innovative scanning electron microscopy techniques such as scanning electron microscopy (SEM), variable pressure SEM (VP-SEM), environmental SEM (ESEM), and the more recent ambiental SEM (ASEM), ending with the cutting edge Cryo-SEM and focused ion beam SEM (FIB SEM), highlighting the pros and cons of several methods with particular emphasis on conventional SEM and VP-SEM. As each technique has its own advantages and disadvantages, the choice of the most appropriate method must be done carefully, based on the specific aim of the study. The evaluation of the drug effects on biofilm requires imaging methods that show the most detailed ultrastructural features of the biofilm. In this kind of research, the use of scanning electron microscopy with customized protocols such as osmium tetroxide (OsO4), ruthenium red (RR), tannic acid (TA) staining, and ionic liquid (IL) treatment is unrivalled for its image quality, magnification, resolution, minimal sample loss, and actual sample structure preservation. The combined use of innovative SEM protocols and 3-D image analysis software will allow for quantitative data from SEM images to be extracted; in this way, data from images of samples that have undergone different antibiofilm treatments can be compared.

scholarly journals Waterborne Polyurea Coatings Filled with Sulfonated Graphene Improved Anti-Corrosion Performance

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 251
Author(s):  
Jijia Zhang ◽  
Jihu Wang ◽  
Shaoguo Wen ◽  
Siwei Li ◽  
Yabo Chen ◽  
...  
Keyword(s):  
Composite Coating ◽  
Water Resistance ◽  
Electrochemical Impedance ◽  
Water Immersion ◽  
Doping Content ◽  
Corrosion Performance ◽  
Water Contact ◽  
Sulfonated Graphene ◽  
Long Time ◽  
Scanning Electron

In this paper, an environmentally friendly waterborne polyurea (WPUA) emulsion and its corresponding coating were prepared, which was characterized by dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and scanning electron microscopy (SEM). To improve the performance of the coating, we doped sulfonated graphene (SG) into WPUA to prepare composite coating (SG/WPUA). SG can be uniformly dispersed in WPUA emulsion and is stable for a long time (28 days) without delamination. The water resistance of the composite coating with 0.3 wt.% SG nanofiller was improved; the water contact angle (WCA) result was SG/WPUA (89°) > WPUA (48.5°), and water absorption result was SG/WPUA (2.90%) < WPUA (9.98%). After water immersion treatment, SEM observation revealed that the SG/WPUA film only generated enlarged microcracks (100 nm) instead of holes (150–400 nm, WPUA film). Polarization curves and electrochemical impedance spectroscopy (EIS) tests show that SG nanosheets with low doping content (0.3 wt.%) are more conducive to the corrosion resistance of WPUA coatings, and the model was established to explain the mechanism.

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