Discussion on Repair Method of Concrete Highway Pavement

2013 ◽  
Vol 321-324 ◽  
pp. 209-212
Author(s):  
Chun Yan Xia
Keyword(s):  
Mechanical Properties ◽  
Preparation Program ◽  
Step Method ◽  
Concrete Technology ◽  
Concrete Material ◽  
Repair Method ◽  
Ordinary Concrete ◽  
One Step ◽  
Highway Pavement

nfluences on properties of the concrete highway pavement were analyzed in this paper, and the optimal formulation materials were gotten to use in the repair of used-broken cement blocks in the experiment. Polyurethane concrete material was prepared, combing the ordinary concrete technology with one-step method of the synthesis of polyurethane hard bubble, and then its mechanical properties of the relevant parameters were measured to determine the optimal preparation program. The results show that the polyurethane concrete also has sufficiently good mechanical properties while it has the characteristic of fast patching.

Effect of Dynamic Crosslinking on Mechanical Properties of PP/EPDM Blends

1993 ◽  
Vol 58 (11) ◽  
pp. 2642-2650 ◽  
Author(s):  
Zdeněk Kruliš ◽  
Ivan Fortelný ◽  
Josef Kovář
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Shear Modulus ◽  
High Impact ◽  
Necessary Condition ◽  
Step Method ◽  
Melt Mixing ◽  
One Step ◽  
High Impact Strength ◽  
Dynamic Curing

The effect of dynamic curing of PP/EPDM blends with sulfur and thiuram disulfide systems on their mechanical properties was studied. The results were interpreted using the knowledge of the formation of phase structure in the blends during their melt mixing. It was shown, that a sufficiently slow curing reaction is necessary if a high impact strength is to be obtained. Only in such case, a fine and homogeneous dispersion of elastomer can be formed, which is the necessary condition for high impact strength of the blend. Using an inhibitor of curing in the system and a one-step method of dynamic curing leads to an increase in impact strength of blends. From the comparison of shear modulus and impact strength values, it follows that, at the stiffness, the dynamically cured blends have higher impact strength than the uncured ones.

Highly Soluble and Transparent of Novel Polyimides Containing Trifluoromethyl and Cyclohexane Units

2011 ◽  
Vol 332-334 ◽  
pp. 1918-1921
Author(s):  
Xin Mo ◽  
Guang Li ◽  
Jian Ming Jiang
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Glass Transition ◽  
Transition Temperature ◽  
Moisture Absorption ◽  
Electronic Materials ◽  
Step Method ◽  
Polar Solvents ◽  
Methyl Cyclohexane ◽  
One Step

Two novel polyimides(PIs) were polymerized from 1,4-bis((4-amino-2-(trifluoromethyl)phenoxy)methyl)cyclohexane, with aromatic tetracarboxylic dianhydrides using the typical one-step method. The inherent viscosity of the PIs were around 0.90dL/g, and they exhibited an excellent solubility and optical property. They were readily soluble not only in some strong polar solvents such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), but also in some low-boiling-point solvents such as chloroform (CDCl3), and tetrahydrofuran (THF). The PIs film showed high optical transparency and colorless with cut-off wavelength in 332nm and 338nm. Meanwhile, the temperature of 10% weight loss in air and nitrogen were higher than 441°C and 449°C respectively, and their glass-transition temperature (Tg) were higher than 348 °C. Furthermore, they possessed good mechanical properties with tensile strengths of 69–71MPa, elongations at break of 11.6–15.4% and low moisture absorption (<2%).Due to their properties, the polyimides could be considered as photoelectric and micro-electronic materials.

scholarly journals Mechanism confirmation of organofunctional silanes modified sodium silicate/polyurethane composites for remarkably enhanced mechanical properties

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuntao Liang ◽  
Ao Gao ◽  
Yong Sun ◽  
Fuchao Tian ◽  
Weili Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Sodium Silicate ◽  
Low Cost ◽  
Substrate Surface ◽  
Flexural Modulus ◽  
Hybrid Network ◽  
Step Method ◽  
One Step ◽  
Polyurethane Composites ◽  
Physical And Chemical

AbstractHybrid reinforced sodium silicate/polyurethane (SS/PU) composites mainly derived from low-cost SS and polyisocyanate are produced by a one-step method based on the addition of 3-chloropropyltrimethoxysilane (CTS). The wettability of SS on PU substrate surface is much improved as CTS content increases from 0.0 to 3.5 wt%. Furthermore, with 2.5 wt% of CTS optimal addition, the fracture surface morphology and elemental composition of the resulting SS/PU composites are characterized, as well as mechanical properties, chemical structure and thermal properties. The results indicate that the CTS forms multiple physical and chemical interactions with the SS/PU composites to induce an optimized organic–inorganic hybrid network structure thus achieving simultaneous improvement of compressive strength, flexural strength, flexural modulus and fracture toughness of the SS/PU composites, with the improvement of 12.9%, 6.6%, 17.5% and 9.7%, respectively. Moreover, a reasonable mechanism explanation for CTS modified SS/PU composites is confirmed. Additionally, the high interface areas of the organic–inorganic phase and the active crosslinking effect of the CTS are the main factors to determine the curing process of the SS/PU composites.

MICROWAVE SINTERING OF NANOCRYSTALLINE 8YSZ: EFFECT OF HEATING SCHEDULE ON MICROSTRUCTURE, IONIC CONDUCTIVITY, AND MECHANICAL PROPERTIES

2009 ◽  
Vol 08 (03) ◽  
pp. 293-298
Author(s):  
MAHDIAR VALEFI ◽  
CAVUS FALAMAKI ◽  
AHAD FATTAHI ◽  
TOURAJ EBADZADEH
Keyword(s):  
Mechanical Properties ◽  
Ionic Conductivity ◽  
Microwave Sintering ◽  
The Novel ◽  
Zirconia Powder ◽  
Step Method ◽  
One Step ◽  
Novel Method ◽  
Heating Schedule ◽  
Sintering Method

Nanocrystalline 8 mol.% yttria-stabilized zirconia powder prepared from a combustion synthesis route has been sintered using microwave (MW) energy by two routes: Conventional one-step and a novel two-step method. The final products from the two routes have been compared regarding their microstructure, ion-conductivity, and mechanical properties. It is shown that it is possible to produce highly dense compacts with significant smaller grains using the novel two-step MW sintering method with significant smaller energy consumption with respect to conventional one-step MW assisted sintering. The novel method is able to produce sintered samples with near similar ionic conductivity at temperatures higher than 700°C and slightly lower mechanical properties at room temperature.

Comparative study of transparent polyimides derived from bis(ether anhydride)s and bis(ester anhydride)s using 2,2′-bis(trifluoromethyl)biphenyl-4,4′-diamine

2016 ◽  
Vol 29 (2) ◽  
pp. 218-226 ◽  
Author(s):  
Yu Zhou ◽  
Guofei Chen ◽  
Wei Wang ◽  
Liping Song ◽  
Xingzhong Fang
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Glass Transition ◽  
Comparative Study ◽  
Step Method ◽  
Glass Transition Temperatures ◽  
Step Procedure ◽  
One Step ◽  
Solution Polycondensation

Two series of polyimides (PIs) derived from bis(ether anhydride)s and bis(ester anhydride)s using 2,2′-bis(trifluoromethyl)biphenyl-4,4′-diamine were synthesized via solution polycondensation. The poly(ether imide)s could be formed by the conventional one-step method, while the poly(ester imide)s were only afforded by the two-step procedure. The resulting PIs had glass transition temperatures ( Tgs) in the range of 224–320°C and exhibited good mechanical properties with tensile strength in the range of 80.5–96.5 MPa, tensile moduli 2.7–6.9 GPa, and elongations at break 1.5–17.3%. It was found that the PIs derived from bis(ether anhydride)s showed higher thermal stability, better solubility, and transparency but lower Tg and higher water absorption compared with bis(ester anhydride)-based PIs due to the different ether and ester linkages.

Bismuth particles imbedded degradable nanohydrogel prepared by one-step method for tumor dual-mode imaging and chemo-photothermal combined therapy

2019 ◽  
Vol 375 ◽  
pp. 122000 ◽  
Author(s):  
Yang Xuan ◽  
Xian-Lin Song ◽  
Xiao-Quan Yang ◽  
Ruo-Yun Zhang ◽  
Zi-Yu Song ◽  
...  
Keyword(s):  
Combined Therapy ◽  
Dual Mode ◽  
Step Method ◽  
One Step

scholarly journals Bio-Based Polyurethane Networks Derived from Liquefied Sawdust

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3138
Author(s):  
Kamila Gosz ◽  
Agnieszka Tercjak ◽  
Adam Olszewski ◽  
Józef Haponiuk ◽  
Łukasz Piszczyk
Keyword(s):  
Biomass Conversion ◽  
Structural Features ◽  
Mechanical Analysis ◽  
Process Efficiency ◽  
Hydroxyl Number ◽  
Step Method ◽  
One Step ◽  
Liquefaction Process ◽  
The Fourier Transform ◽  
Liquefaction Temperature

The utilization of forestry waste resources in the production of polyurethane resins is a promising green alternative to the use of unsustainable resources. Liquefaction of wood-based biomass gives polyols with properties depending on the reagents used. In this article, the liquefaction of forestry wastes, including sawdust, in solvents such as glycerol and polyethylene glycol was investigated. The liquefaction process was carried out at temperatures of 120, 150, and 170 °C. The resulting bio-polyols were analyzed for process efficiency, hydroxyl number, water content, viscosity, and structural features using the Fourier transform infrared spectroscopy (FTIR). The optimum liquefaction temperature was 150 °C and the time of 6 h. Comprehensive analysis of polyol properties shows high biomass conversion and hydroxyl number in the range of 238–815 mg KOH/g. This may indicate that bio-polyols may be used as a potential substitute for petrochemical polyols. During polyurethane synthesis, materials with more than 80 wt% of bio-polyol were obtained. The materials were obtained by a one-step method by hot-pressing for 15 min at 100 °C and a pressure of 5 MPa with an NCO:OH ratio of 1:1 and 1.2:1. Dynamical-mechanical analysis (DMA) showed a high modulus of elasticity in the range of 62–839 MPa which depends on the reaction conditions.

scholarly journals Is Dialdehyde Chitosan a Good Substance to Modify Physicochemical Properties of Biopolymeric Materials?

2021 ◽  
Vol 22 (7) ◽  
pp. 3391
Author(s):  
Sylwia Grabska-Zielińska ◽  
Alina Sionkowska ◽  
Ewa Olewnik-Kruszkowska ◽  
Katarzyna Reczyńska ◽  
Elżbieta Pamuła
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Physicochemical Properties ◽  
Silk Fibroin ◽  
Three Dimensional ◽  
Microscopy Imaging ◽  
Maximum Deformation ◽  
One Step ◽  
Chitosan Blends ◽  
Fourier Transfer Infrared Spectroscopy

The aim of this work was to compare physicochemical properties of three dimensional scaffolds based on silk fibroin, collagen and chitosan blends, cross-linked with dialdehyde starch (DAS) and dialdehyde chitosan (DAC). DAS was commercially available, while DAC was obtained by one-step synthesis. Structure and physicochemical properties of the materials were characterized using Fourier transfer infrared spectroscopy with attenuated total reflectance device (FTIR-ATR), swelling behavior and water content measurements, porosity and density observations, scanning electron microscopy imaging (SEM), mechanical properties evaluation and thermogravimetric analysis. Metabolic activity with AlamarBlue assay and live/dead fluorescence staining were performed to evaluate the cytocompatibility of the obtained materials with MG-63 osteoblast-like cells. The results showed that the properties of the scaffolds based on silk fibroin, collagen and chitosan can be modified by chemical cross-linking with DAS and DAC. It was found that DAS and DAC have different influence on the properties of biopolymeric scaffolds. Materials cross-linked with DAS were characterized by higher swelling ability (~4000% for DAS cross-linked materials; ~2500% for DAC cross-linked materials), they had lower density (Coll/CTS/30SF scaffold cross-linked with DAS: 21.8 ± 2.4 g/cm3; cross-linked with DAC: 14.6 ± 0.7 g/cm3) and lower mechanical properties (maximum deformation for DAC cross-linked scaffolds was about 69%; for DAS cross-linked scaffolds it was in the range of 12.67 ± 1.51% and 19.83 ± 1.30%) in comparison to materials cross-linked with DAC. Additionally, scaffolds cross-linked with DAS exhibited higher biocompatibility than those cross-linked with DAC. However, the obtained results showed that both types of scaffolds can provide the support required in regenerative medicine and tissue engineering. The scaffolds presented in the present work can be potentially used in bone tissue engineering to facilitate healing of small bone defects.

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