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Objectives: To analyze the incorporation of cardanol trimethacrylate monomer (CTMA), derived from the cashew nut shell liquid, as a substitute for Bis-GMA in acrylic resins formulations and its effect on experimental resin composites’ physicochemical and mechanical properties. Materials and methods: The intermediary cardanol epoxy was synthesized via cardanol epoxidation, followed by the synthesis of CTMA through methacrylic anhydride solvent-free esterification. Experimental resin composites were formulated with an organic matrix composed of Bis-GMA/TEGDMA (50/50 wt %) (control). CTMA was gradually added to replace different proportions of Bis-GMA: 10 wt % (CTMA-10), 20 wt % (CTMA-20), 40 wt % (CTMA-40), and 50 wt % (CTMA-50). The composites were characterized by degree of conversion, water sorption and solubility, viscosity, thermogravimetric analysis, dynamic mechanical analysis, flexural strength and elastic modulus. Data were analyzed with one-way ANOVA and Tukey’s post-hoc test (α = 0.05), except for water sorption data, which were analyzed by Kruskall-Wallis and Dunn’s method. Results: CTMA-based and control composites did not show statistically significant differences regarding degree of conversion, flexural strength and elastic modulus. CTMA reduced the viscosity and solubility compared to the Bis-GMA-based composite. The CTMA-40 and CTMA-50 exhibited significantly lower water sorption compared to the control. Also, acceptable thermal stability and viscoelastic properties were obtained for safe use in the oral cavity. Conclusions: Incorporating CTMA into composites resulted in similar chemical and mechanical properties compared to Bis-GMA-based material while reducing viscosity, water sorption and solubility. Clinical relevance: CTMA could be used as a trimethacrylate monomer replacing Bis-GMA in resin composites, thereby minimizing BPA exposure. [ABSTRACT FROM AUTHOR]

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This study focuses on polyamide 6/organo-modified montmorillonite (PA6/OMMT) nanocomposites as potential liner materials, given the growing interest in enhancing the performance of type IV composite overwrapped hydrogen storage pressure vessels. The mechanical properties of PA6/OMMT composites with varying filler concentrations were investigated across a temperature range relevant to hydrogen storage conditions (−40 °C to +85 °C). Liner collapse, a critical issue caused by rapid gas discharge, was analyzed using an Ishikawa diagram to identify external and internal factors. Mechanical testing revealed that higher OMMT content generally increased stiffness, especially at elevated temperatures. The Young's modulus and first yield strength exhibited non-linear temperature dependencies, with 1 wt. per cent OMMT content enhancing yield strength at all tested temperatures. Dynamic mechanical analysis (DMA) indicated that OMMT improves the storage modulus, suggesting effective filler dispersion, but it also reduces the toughness and heat resistance, as evidenced by lower glass transition temperatures. This study underscores the importance of optimizing OMMT content to balance mechanical performance and thermal stability for the practical application of PA6/OMMT nanocomposites in hydrogen storage pressure vessels. [ABSTRACT FROM AUTHOR]

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To study the effect of temperature on the dynamic mechanical properties of marble, dynamic compres- sion tests, XRD, and SEM microscopic tests were conducted on marble samples at room temperature (25 °C) and after exposure to high temperatures (200 °C, 400 ℃, 600 °C, and 800 °C). The relationship between the dynamic mechani- cal properties of marble and temperature, as well as the microscopic damage mechanisms, were explored. The results show that the dynamic compressive stress-strain curves of marble after high-temperature exposure can be divided into 3 stages: elastic, yield, and failure. The peak stress and failure characteristics of marble exhibit a significant tempera- ture effect: as the temperature increases, the peak stress of marble gradually decreases, and the degree of fragmentation intensifies. The dynamic mechanical properties of marble are closely related to its mineral composition and crystal structure. Between 200 °C and 600 °C, micro-defects increase, and dolomite undergoes thermal decomposition and transformation. At 800 °C, mineral decomposition produces CO₂ gas and calcium hydroxide, and the crystal structure undergoes melting damage, leading to severe internal damage and increased plasticity, resulting in a substantial decline in macroscopic mechanical properties. [ABSTRACT FROM AUTHOR]

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Alumina ceramic is an ideal candidate for armor protection, but it is limited by the difficult molding or machining process. Three-dimensional printing imparts a superior geometric flexibility and shows good potential in the preparation of ceramics for armor protection. In this work, alumina ceramics were manufactured via 3D printing, and the effects of different monomers on the photosensitive slurry and sintered ceramics were investigated. The photosensitive slurries using dipropylene glycol diacrylate (DPGDA) as a monomer displayed the optimal curing performance, with a low viscosity, small volume shrinkage and low critical exposure energy, and each of the above properties was conducive to a good curing performance in 3D printing, making it a suitable formula for 3D-printed ceramic materials. In the 3D-printed ceramics with DPGDA as a monomer, a dense and uniform microstructure was exhibited after sintering. In comparison, the sample with trimethylolpropane triacrylate (TMPTA) showed an anisotropic microstructure with interlayer gaps and a porosity of about 9.8%. Attributed to the dense uniform microstructure, the sample with DPGDA exhibited superior properties, including a relative density of 97.5 ± 0.5%, a Vickers hardness of 19.4 ± 0.8 GPa, a fracture toughness of 2.6 ± 0.27 MPa·m1/2, a bending strength of 690 ± 54 MPa, and a dynamic strength of 3.7 ± 0.6 GPa at a strain rate of 1200 s−1. [ABSTRACT FROM AUTHOR]

In this study, modifying the austenitizing temperature offers a strategically viable way towards creating blocky retained austenite (BRA) with varying sizes and morphologies in nanostructured bainitic steel, in strikingly contrast to the conventional method of adjusting the austempering temperature. Dynamic tensile and compressive evaluation at different strain rates of 1 × 103 s−1 and 5 × 103 s−1 were carried out to gain insights into the effect of BRA stability on the dynamic mechanical properties and its intrinsic relationship with high strain rates. Additionally, the phase transformations and the triggered transformation-induced plasticity (TRIP) effects of BRA at different high strain rates were analyzed. The results reveal that during dynamic deformation, most of metastable BRA underwent a two-stage martensitic transformation of γ→εM and εM→α′M, while the filmy retained austenite exhibits minimal phase transformation. BRA dominates the TRIP effect under the extremely short deformation time and adiabatic heating conditioning. Consequently, samples containing more and larger-sized BRA demonstrated superior dynamic mechanical properties, including strength and fracture strain. As the strain rate increases, the TRIP effect induced by less stable BRA contributes to more pronounced enhancement of properties. Besides the deterioration effect originating from the early transformed brittle martensite also gradually intensifies with the strain rate, which is manifested by the appearance of quasi-cleavage facets at the fracture comparable to the BRA size. Nevertheless, during dynamic deformation, the metastable BRA induced TRIP effect significantly enhances the mechanical properties, outweighing its deteriorating effect. Moreover, less stable BRA should be favored at higher the strain rate.

Through a series of static mechanical tests and (SHPB) dynamic impact tests, the static and dynamic mechanical parameters of rock as represented by yellow sandstone are determined, and the Holmquist-Johnson-Cook model parameters of the rock are calibrated using the test data and theoretical calculations. The feasibility of a numerical model is verified, and numerical analysis of the SHPB impact process under different radial pressure pre-loading is carried out on the basis of good verification. The results show that with increasing impact load, the degree of rock breakage increases, as does the dynamic tensile strength. With the application of increasing pre-static pressure, the dynamic tensile strength of the rock decreases gradually, and the maximum radial cumulative strain increases continuously under a given impact pressure, indicating that micro-cracks in the rock develop initially and then expand under the influence of pre-static pressure; the rock is more easily broken, and its weakening degree increases. Under coupled dynamic and static loading, the energy utilization rate of rock in the Brazilian splitting process is jointly affected by axial compression ratio and impact load. Too large a pressure ratio will reduce the strain-rate sensitivity of rock, resulting in low energy utilization rate, while too low an axial compression ratio will make the dynamic tensile strength of rock relatively high, which is not conducive to tensile failure. Therefore, on the premise of clear fracture form requirements, a suitable combination of axial compression ratio and impact velocity can improve the rock crushing effect and energy utilization rate. [ABSTRACT FROM AUTHOR]

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In this study, the traditional mini split Hopkinson tension bar (SHTB) was enhanced for the dynamic mechanical performance testing of single fiber/resin interface of composites. Single Aramid III fibers were modified using a polyamine modification treatment. Quasi-static and dynamic tensile tests of modified single Aramid III fibers were conducted using an electronic tensile testing machine and mini SHTB. The test results indicated that the surface modification employing the Catechol-Tetraethylenepentamine (Cat-TEPA) approach had a negligible effect on the tensile mechanical properties of single Aramid III fibers. The microdroplet method was introduced to measure the dynamic interfacial shear strength (IFSS) of Aramid III fiber/waterborne polyurethane resin using a mini SHTB. The dynamic shear test results revealed an increase in the dynamic shear strength of the modified Aramid III fiber/resin interface from 36.16 MPa to 41.51 MPa. Furthermore, the Scanning Electron Microscope (SEM) photography of the modified single Aramid III fiber after debonding exhibited regular grid structures on the debonding area, which can prevent debonding between the single fiber and the microdroplet, thereby enhancing interfacial shear performance. [ABSTRACT FROM AUTHOR]

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Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, through a series of static mechanical tests and split Hopkinson pressure bar (SHPB) dynamic impact tests, the static and dynamic mechanical parameters of yellow sandstone are determined, and the Holmquist-Johnson-Cook model parameters of the rock are determined by the test data and theoretical calculation. The feasibility of a numerical model is verified, based on which the SHPB impact process under different axial pressure is subjected to numerical analysis. The results show that with increasing impact load, the degree of rock breakage increases, and the dynamic compressive strength and dynamic elastic modulus increase continuously. With the application and increase of axial pressure, the dynamic compressive strength and dynamic elastic modulus of the rock decrease gradually under the same impact load, and the maximum cumulative strain keeps increasing, indicating that under the influence of axial pressure, micro-cracks in the rock have initially developed and expanded. With increasing axial pressure, the rock is more vulnerable to breakage, and its weakening degree keeps increasing. The energy utilization rate of one-dimensional dynamic and static combined loading is affected by the axial compression ratio and impact load. At low axial compression ratio, the rock has high impact resistance but high energy utilization rate; at high axial compression ratio, the rock has low impact resistance but low energy utilization rate. Therefore, the combination of axial compression ratio and impact velocity can improve the crushing effect and energy utilization rate on the premise of clear crushing form requirements. [ABSTRACT FROM AUTHOR]

This study focuses on polyamide 6/organo-modified montmorillonite (PA6/OMMT) nanocomposites as potential liner materials, given the growing interest in enhancing the performance of type IV composite overwrapped hydrogen storage pressure vessels. The mechanical properties of PA6/OMMT composites with varying filler concentrations were investigated across a temperature range relevant to hydrogen storage conditions (−40 °C to +85 °C). Liner collapse, a critical issue caused by rapid gas discharge, was analyzed using an Ishikawa diagram to identify external and internal factors. Mechanical testing revealed that higher OMMT content generally increased stiffness, especially at elevated temperatures. The Young’s modulus and first yield strength exhibited non-linear temperature dependencies, with 1 wt. per cent OMMT content enhancing yield strength at all tested temperatures. Dynamic mechanical analysis (DMA) indicated that OMMT improves the storage modulus, suggesting effective filler dispersion, but it also reduces the toughness and heat resistance, as evidenced by lower glass transition temperatures. This study underscores the importance of optimizing OMMT content to balance mechanical performance and thermal stability for the practical application of PA6/OMMT nanocomposites in hydrogen storage pressure vessels.

Reclaimed rubbers with different Mooney viscosity were used to replace all the aromatic oil and part of carbon black in the formula of passenger car tyre tread compounds. The effects of Mooney viscosity and carbon black replacement ratio of reclaimed rubber on curing characteristics, physical and mechanical properties, aging resistance and dynamic mechanical properties of tread vulcanizates were investigated. The results showed that when the replacement mass ratio of reclaimed rubber to carbon black was 5/1, the tread vulcanizates had better physical and mechanical properties and aging resistance. Compared with high Mooney viscosity reclaimed rubber, the tread vulcanizate with low Mooney viscosity reclaimed rubber had higher curing efficiency and better tensile properties. Both high and low Mooney viscosity reclaimed rubber could reduce the rolling resistance of tread vulcanizates, while the wear resistance was maintained.

Since the surrounding rocks of underground tunnels are frequently suffered from the dynamic disturbance of mechanical percussion drilling and explosive blasting, it is significantly meaningful to investigate the mechanical properties and failure behaviors of rock material with a tunnel-shaped opening under dynamic loads. In this work, seven groups of prismatic samples, including the intact samples and the samples with a circular opening of three kinds of diameters, a square opening, a horseshoe-shaped opening and a D-shaped opening, were prepared for dynamic compressive loading. The results show that the prismatic specimens satisfy the stress uniformity condition in impact tests using SHPB testing system with a bar diameter of 50 mm. The weakening effects of the existed openings on the dynamic compressive strength, elastic modulus and peak strain of rocks are closely associated with the size and shape of opening and the loading direction. Based on the energy parameters of the samples, the dissipated energy density of each group of samples can be solved. The failure degree of the samples characterized by dissipated energy density and fractal dimension are in good agreement. Besides, the failure mode of the intact specimen belongs to splitting tensile failure, while that of the pre-holed specimens can be classified as shear-dominated failure due to the coalescence of the openings and the shear cracks occurring along the diagonals of the specimens. The test results provide some insights into the mechanical behavior of rock materials under dynamic loads and lay an important theoretical foundation for support design and rock disaster prevention of underground tunnel.

Due to the different composition of cutting fluid will affect the failure stress of the material in the shear deformation area, so the rational use of cutting fluid can optimize the cutting force and the surface integrity of parts. Four kinds of hat-shaped samples with shear band widths were designed. The effects of different cutting fluids on mechanical properties of ultrahigh strength steel at different shear strain rates were studied in this paper by SHPB, and verified by cutting experiments. The stress–strain curve, shear failure stress, fracture morphology and cutting force were studied systematically. Experimental results show that the stress remains stable for a period of time with the increases of strain after strain hardening at γs= 10.03 × 104 1/s. All shear fracture is ductile fracture and at γs

Herein, the concept of ionic cross-linking was first introduced into the preparation of thermoplastic vulcanizates (TPV). Oil-resistant TPV was developed based on acrylate rubber (ACM) and polyoxymethylene formaldehyde (POM) using Ca(OH)2 as the cross-linking agent. The physical and mechanical properties, aging resistance, dynamic mechanical properties, micromorphology, and energy loss of the composites under covalent cross-linking networks and ion cross-linking networks with different degrees of cross-linking were systematically studied. The results showed that Ca2+ could form metal ion binding with the -COOH of ACM, playing a cross-linking role for ACM. Compared with the covalent bonding system, the 100% constant tensile stress of TPV in the ionic bonding system can be increased by 31% and the elongation increased by 14.5%. And exhibits better elasticity and lower hysteresis loss below 140 °C. The increase in dispersed phase modulus increases the phase domain of dispersed phase, weakens the binding with matrix, weakens the tensile strength, increases the intrusion of hot oxygen and hot oil, increases the energy storage modulus, and decreases the loss modulus. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Natural rubber (NR)/ethylene-propylene-diene rubber (EPDM) blends with different blending ratios were prepared, the heat-vulcanized NR/EPDM vulcaniztes were analyzed by the stress-strain test, the blend with the most serious co-vulcanization problem in the process of heat-vulcanization was selected for radiation processing with diffe-rent radiation absorption dose by radiation cross-linking technology, and the optimal radiation absorption dose was preferred. Radiation treatment of the heat-vulcanized NR/EPDM vulcaniztes with different blending ratios was carried out with the optimal absorption dose, and the properties of the heat-vulcanized NR/EPDM vulcaniztes before and after radiation treatment were compared. The results showed that the comprehensive mechanical properties of the heat-vulcanized NR/EPDM vulcanizte were the worst when the mass ratio of NR to EPDM was 40/60; when the radiation absorption dose was 100 kGy, the comprehensive mechanical properties of NR/EPDM blends were the best, and modulus at 100% of NR/EPDM blends with different blending ratios all increased and there was no significant difference in the magnitude of the increase in modulus at 100% of NR/EPDM blends with different blending ratios after radiation treatment; the curves of tensile strength and elongation at break of NR/EPDM blends with different blending ratios all changed from the “U-shaped” before radiation treatment to the approximate linear after radiation treatment; after radiation treatment elongation at break of NR/EPDM blends all decreased and the magnitudes of the increase in elongation at break of EPDM phase were larger than those of NR phase in NR/EPDM blends.

HNBR/FKM composites were prepared by compounding carbon black (CB), hydroxide zinc monomethacrylate (HZMMA) and carbon nanotubes (CNTs) to modify hydrogenated nitrile rubber (HNBR)/ fluororubber (FKM) blend, and the effects of the composite reinforcing agent on the curing characteristics of HNBR/FKM blends, and the physico-mechanical properties, dynamic mechanical properties and thermal-oxydative aging properties of the vulcanized rubber were investigated. The results showed that the curing rate of HNBR/FKM compo-sites was accelerated and the cross-linking degree was increased when HZMMA and CNTs were added, and the physico-mechanical properties of HNBR/FKM composites were significantly improved under the synergistic effect of HZMMA and CNTs. HNBR/FKM composites reinforced by HZMMA and CNTs of 3 phr (mass) exhibited the highest retention rate of elongation at break and the lowest change rate of hardness after thermal-oxydative aging compared with that reinforced by pure CB. As the addition amount of CNTs increased, the glass transition temperature of HNBR/FKM composites moved towards the lower temperature and the loss factor decreased gradually.

The preferred emulsifier was used to emulsify the plasticizer naphthenic oil (NAP), and uniform and stable NAP emulsion was prepared. The NAP-plasticized natural rubber (NR)/silica (SiO2) (NAP/NR/SiO2) composite was prepared using the resulting NAP emulsion, NR latex and SiO2 slurry by wet mixing process, and the effects of NAP addition amount on Mooney viscosity, physical and mechanical properties, dynamic mechanical properties, dispersion of SiO2, thermal air aging resistance and flexural cracking property of NAP/NR/SiO2 composites were studied. The results showed that Mooney viscosity of NAP/NR/SiO2 composite was significantly lower than that of NR/SiO2 composite, Payne effect was significantly weakened, and dynamic mechanical properties and proces-sability improved significantly. When NAP addition amount was 10 phr (mass), NAP/NR/SiO2 composite had the best comprehensive performance, and tensile strength of NAP/NR/SiO2 composite decreased slightly, whereas elongation at break increased to varying degrees when compared with those of NR/SiO2 composite. Thermal air aging resistance and flexural cracking property of NR/SiO2 composite improved after the addition of NAP.

A planetary ball mill was used to treat the pyrolytic carbon black (CBp) of waste tire by dry modification with 3 types of modified resins, PA, PF-203 and Polstal-PC as the modifiers, the changes of physico-chemical properties and structure of CBp before and after modification were explored, and the effects of modified CBp on curing characteristics, cross-linking density, mechanical properties and dynamic mechanical properties of natural rubber were investigated. The results showed that the particle size of CBp decreased with the extension of milling time. The mo-dified resin Polstal-PC had the most obvious grinding effect, and compared with unmodified CBp, the total specific surface area of CBp modified by Polstal-PC increased from 65.1 m2/g to 97.4 m2/g and the specific surface area of the outer surface increased from 63.0 m2/g to 71.6 m2/g. All of the 3 type of modifiers contributed to vulcanization of natural rubber, and CBp modified by Polstal-PC could significantly improve tensile strength, modulus at 300% and cross-linking density of natural rubber vulcanizate, and the addition of CBp modified by tackifying resin PA could cause the decrease of modulus and cross-linking density. CBp modified by Polstal-PC had the best enhancement effect on natural rubber, and natural rubber vulcanizate showed the best comprehensive performance when the addition amount of CBp modified by Polstal-PC was 2 phr (mass, similarly hereinafter), and as far as CBp modified by Polstal-PC was concerned, the improvement of rolling resistance of natural rubber vulcanizate was better than the loss of wet skid resistance. However, storage modulus of natural rubber vulcanizate increased significantly when the addition amount of CBp modified by Polstal-PC was more than 3 phr.

The natural latexes with different protein contents were prepared by centrifugation and then treated by alkaline protease to hydrolyze protein on the rubber particle surface, and the effects of protein hydrolysates on curing characteristics and dynamic behavior of natural rubber were studied. The results showed that with the increment of centrifugation times nitrogen mass fraction decreased from 0.27% to 0.13%, complex viscosity of raw rubber and curing rate of compound decreased, cross-linking density and mechanical properties of natural rubber vulcanizates declined, and storage modulus reduced under strain and frequency sweep. However, complex viscosity, curing rate, mechanical properties and storage modulus of natural rubber treated by multi-centrifugation and enzyme increased compared with those of natural rubber treated by only multi-centrifugation, due to the role of protein hydrolysates, and especially for the natural rubber treated by twice centrifugation and enzyme, curing rate could reach 17.8 min-1 and tensile strength could reach 23.73 MPa, which were significantly higher than curing rate of 9.59 min-1 and tensile strength of 20.52 MPa of natural rubber treated by only twice centrifugation, respectively.

Butadiene-acrylonitrile-butylacrylate terpolymer (BNBR) was synthesized by emulsion polymerization method. The effects of amount of initiator, emulsifier and regulator of relative molecular weight on the emulsion polymerization rate were investigated. And the microstructure and dynamic mechanical properties were characterized. The results showed that the polymerization rate increased and the reaction induction period shortened with increasing polymerization temperature. The increasing amount of initiator and emulsifier could increase the reaction rate, while the change in the amount of relative molecular weight regulator had little effect on the reaction rate. The apparent activation energy of the BNBR was 27.97 kJ/mol, and the particle size distribution of BNBR latex was uniform. The glass transition temperature of BNBR was lower than that of nitrile rubber（NBR）with a difference of about 10 ℃. BNBR had better dynamic mechanical pro-perties at low temperature than NBR.

Surface modification of traditional carbon black (CB) was adopted by three methods, and the changes about the surface morphology and structure of CB before and after modification were investigated, and the modified CB was used to fill natural rubber (NR)/polybutadiene rubber (BR) blend. The effects of modified CB on the mechanical properties, curing characteristics, and dynamic mechanical properties of composites were investigated. The results showed that compared with the unmodified CB, the surface roughness of CB increased after refining particle size, raising the pH value and lignin modification. The refined CB had the higher specific area, and much more loose secondary structures for the CB with high pH value, as well as the increased particle size in lignin system slightly. For the CB filled NR/BR blend, refining particle aize and raising pH value could promote its mechanical properties, wear resistance and wet skid resistance significantly, but make an obvious vulcanization delay effect. After modification by lignin, the vulcanized blend filled with CB presented a lower mechanical properties and wear resistance varyingly.

Alumina ceramic is an ideal candidate for armor protection, but it is limited by the difficult molding or machining process. Three-dimensional printing imparts a superior geometric flexibility and shows good potential in the preparation of ceramics for armor protection. In this work, alumina ceramics were manufactured via 3D printing, and the effects of different monomers on the photosensitive slurry and sintered ceramics were investigated. The photosensitive slurries using dipropylene glycol diacrylate (DPGDA) as a monomer displayed the optimal curing performance, with a low viscosity, small volume shrinkage and low critical exposure energy, and each of the above properties was conducive to a good curing performance in 3D printing, making it a suitable formula for 3D-printed ceramic materials. In the 3D-printed ceramics with DPGDA as a monomer, a dense and uniform microstructure was exhibited after sintering. In comparison, the sample with trimethylolpropane triacrylate (TMPTA) showed an anisotropic microstructure with interlayer gaps and a porosity of about 9.8%. Attributed to the dense uniform microstructure, the sample with DPGDA exhibited superior properties, including a relative density of 97.5 ± 0.5%, a Vickers hardness of 19.4 ± 0.8 GPa, a fracture toughness of 2.6 ± 0.27 MPa·m1/2, a bending strength of 690 ± 54 MPa, and a dynamic strength of 3.7 ± 0.6 GPa at a strain rate of 1200 s−1.

In this study, the traditional mini split Hopkinson tension bar (SHTB) was enhanced for the dynamic mechanical performance testing of single fiber/resin interface of composites. Single Aramid III fibers were modified using a polyamine modification treatment. Quasi-static and dynamic tensile tests of modified single Aramid III fibers were conducted using an electronic tensile testing machine and mini SHTB. The test results indicated that the surface modification employing the Catechol-Tetraethylenepentamine (Cat-TEPA) approach had a negligible effect on the tensile mechanical properties of single Aramid III fibers. The microdroplet method was introduced to measure the dynamic interfacial shear strength (IFSS) of Aramid III fiber/waterborne polyurethane resin using a mini SHTB. The dynamic shear test results revealed an increase in the dynamic shear strength of the modified Aramid III fiber/resin interface from 36.16 MPa to 41.51 MPa. Furthermore, the Scanning Electron Microscope (SEM) photography of the modified single Aramid III fiber after debonding exhibited regular grid structures on the debonding area, which can prevent debonding between the single fiber and the microdroplet, thereby enhancing interfacial shear performance.

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Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

TiB2–SiC/B4C composite ceramics have application as lightweight armor ceramic material, and therefore, it is particularly important to research their dynamic mechanical properties and fracture behavior under high strain rates. In the present research, the dynamic compression strength and Hugoniot elastic limit (HEL) of these composite ceramics were determined by split Hopkinson pressure bar technology and plate impact equipment, respectively. The experimental investigation results illustrated that the composite ceramic exhibited outstanding dynamic compression strength (2750 MPa) and displayed a remarkable strain‐rate strengthening effect. The HEL was calculated as 18.49 GPa, and the commonly used P–μ form of the Hugoniot curve was derived from the calculated data of the shock velocity and particle velocity. The dynamic fracture morphologies of the TiB2–SiC/B4C composite ceramic and monolithic B4C ceramic (correlation data) at macro and micro scales were observed and analyzed in detail. The dynamic fracture mechanisms were summarized in‐depth into the following three points. First, the strengthening mechanism offered by the in situ second phases could significantly improve the comprehensive property. Second, the mixed‐inter/transgranular fracture mode was conducive to energy absorption. Third, the anchoring effect and thermal expansion coefficient mismatch contributed to the energy dissipation and fracture toughness improvement. This work provides the foundation for the application and development of lightweight armor ceramic materials. [ABSTRACT FROM AUTHOR]

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Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The uniaxial compression test and dynamic compression test of C30, C50, and C80 concrete were carried out. The effects of strength grade and strain rate (ε′) on dynamic mechanical properties of concrete were analyzed in terms of dynamic compressive strength, dynamic increase factor (DIF), dynamic peak strain, and dynamic peak toughness. And the strain rate sensitivity of mechanical indexes and DIF fitting model of concrete with different strength grades were explored. The results show that the dynamic compressive strength, DIF and dynamic peak toughness of concrete with different strength grades all have obvious strain rate effects. With the increase of strength grade of concrete, the dynamic peak strain of concrete decreases continuously, and the strain rate sensitivity of dynamic compressive strength and dynamic peak toughness of concrete increases continuously. The mechanical indexes of C80 concrete have the strongest sensitivity to the strain rate. The DIF empirical formula of Comite Euro‐International du Beton (CEB) cannot fit the DIF of C30 and C80 concrete effectively. There is a critical strain rate beyond which the strain rate effect of DIF is significantly enhanced. With the increase of strength grade of concrete, the critical strain rate of concrete decreases continuously. The piecewise linear fitting of DIF and lgε′ of concrete with different strength grades shows good results. [ABSTRACT FROM AUTHOR]

In order to investigate the dynamic compressive mechanical properties of mortar-concrete joint interface, three different specimens of concrete, mortar and mortar-concrete joint interface were designed, and their static and dynamic mechanical properties were investigated by hydraulic servo machine and split Hopkinson bar (SHPB). The damage morphology and mechanical characteristic parameters of specimens under different joint conditions were obtained from the test. At the same time, the dynamic enhancement effect of three different spcimens was analyzed and its mechanism was revealed from the mesoscopic level by using CT scanning technology. The results show that under static action, the overrall compressive strength of joint specimens is between mortar specimens and concrete specimens. Under dynamic action, the compressive strength of three different specimens increases correspondingly with increasing strain rate. Concrete has stronger sensitivity to strain rate and mortar has the weakest sensitivity. Compared with concrete specimens, the integrity of mortar and mortar-concrete joint specimens after compressive damage is significantly improved. Based on experimental data and CEB formula proposed by Comité Euro-International du Béton, the dynamic increase factor (DIF) and strain rate mathematical model suitable for three different materials are optimized. [ABSTRACT FROM AUTHOR]

"The structures of three self-made rare earth-based cis-1,4-polybutadiene rubber with narrow distribution were analyzed, and the relationships between cis-1,4-unit content and properties were studied. The results showed that the three samples had all narrow distribution (molecular weight distribution index ranged from 2.55 to 2.74), and the Mooney viscosity of raw rubber was in the range of 45±5, among which the higher cis-1,4-unit content was slightly higher. All of them had good scorching safety, similar curing rate and good combination with carbon black; good physical and mechanical properties, heat aging resistance, wear resistance and resilience. With increase of cis-1,4-unit content, the compression heat generation and rolling resistance of the polybutadiene rubber decreased, and the dyna-mic fatigue resistance decreased slightly. "

Natural rubber with different nitrogen content (NR-P) was prepared by coagulation from fresh hevea latex with papain as granulation agent. The physical and chemical properties, curing cha-racteristics, physical and mechanical properties, compression fatigue heat build-up and dynamic mechanical properties of NR-P were studied and compared with that of acid-coagulated natural rubber (NR-A).The results showed that with decrease of nitrogen content, the initial plasticity of NR-P decreased first and then leveled off, while the plasticity retention index decreased slightly. The curing rate of the rubber compound with NR-P became faster, the modulus at 300%, tensile strength first increased and then decreased slightly. Besides, the heat build-up and rolling resistance of natural rubber vulcanizate also showed a decreasing trend. Compared with NR-A, the nitrogen content of NR-P was lower, but the initial plasticity was higher and plasticity retention index was slightly lower, and the curing rate and tensile strength were also better than that of NR-A. When the mass fraction of nitrogen of natural rubber was in the range of 0.18% to 0.23%, NR-P compounds exhibited faster curing rate, better mechanical properties, lower compression fatigue heat build-up and dynamic mechanical properties.

The surface integrity of ultra-high-strength steel has a significant influence on service performance, and cutting fluid plays an important role in maintaining surface integrity in production. In this paper, the surface integrity of ultra-high-strength steel 45CrNiMoVA was investigated under three cutting fluids: HY-103 (micro-emulsion), TRIM E709 (emulsion), and Vasco 7000 (micro-emulsion) from the aspects of cutting force, surface morphology, residual stress, micro hardness, microstructure, etc. The results showed that the changing trend of the cutting forces in three directions is HY-103 > Vasco 7000 > TRIM E709. The TRIM E709 contains the maximum lubricants, which reduce cutting force and Sa roughness, while the Vasco 7000 contains the minimum corrosive elements, which results in the least pitting. Both tangential and axial stresses under cutting fluid are tensile stresses. TRIM E709 and Vasco 7000 are reduced axially by 4.45% and 7.60% relative to HY-103, respectively. The grain refinement layer depths of HY-103, TRIM E709, and Vasco 7000 are 9 μm, 4 μm, and 8 μm, respectively, and TRIM E709 can induce recrystallized grains to grow along {001} of the sample cross section, which results from the lowest cooling rate. This work may provide an innovative control strategy for cutting fluid to improve surface integrity and service performance. [ABSTRACT FROM AUTHOR]

Concrete modified with Superabsorbent Polymers (SAP) has excellent frost resistance, self-sealing and self-healing property. However, the influence of SAP particle size on the dynamic mechanical behavior of concrete is still unclear. The influence of SAP particle size on the total porosity and macropore (＞100 μm) porosity of concrete was studied with the mercury intrusion method and the image analysis method. The effect of SAP particle size on the quasi-static and dynamic mechanical properties of concrete was also analyzed. The results show that the dynamic compressive strength and elastic modulus of concrete may decrease with the adding of SAP, and the larger the SAP particle size is, the greater the reduction ratio of compressive strength and elastic modulus of concrete will become. Under the dynamic and quasi-static compression, increasing the SAP particle size will reduce the dynamic compressive strength and dynamic elastic modulus of concrete. [ABSTRACT FROM AUTHOR]

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)