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91.
Effect of various efficient vulcanization (EV) sulfur cure systems on the compression set of a nitrile rubber filled with carbon black and silica/silane fillers was examined. The cure systems had different amounts of thiuram and sulfenamide accelerators and elemental sulfur, whilst the loading of zinc oxide and stearic acid activators was kept constant. The fillers had surface areas from 35 to 175 m2/g. In this study, the lowest compression set was measured for the rubber filled with carbon black with 78 m2/g surface area, which was cured with an EV cure system made of a small amount of elemental sulfur and large amounts of the two accelerators. Interestingly, a small change in the amount of elemental sulfur had a bigger effect on the compression set than did large changes in the loading of the accelerators in the cure system. Among the fillers, carbon black caused less compression set of the rubber vulcanizate than the silica/silane system did. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41512. 相似文献
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Kai LONG Xiaoyu YANG Nouman SAEED Ruohan TIAN Pin WEN Xuan WANG 《Frontiers of Mechanical Engineering》2021,16(3):593-606
Frontiers of Mechanical Engineering - This paper proposes a novel method for the continuum topology optimization of transient vibration problem with maximum dynamic response constraint. An... 相似文献
95.
Graphene nanosheets-supported Sn-Pt bimetallic nanoparticles (GNs/Sn-Pt) were prepared by precipitation method. The obtained GNs/Sn-Pt was used as a photocatalyst for photodegradation of Basic Green 5 (BG5) in aqueous solution under sunlight. The morphology and photodegradation study was performed by SEM and UV–VIS spectrophotometry, respectively. The SEM image showed the presence of Sn and Pt on GNs, being confirmed by energy dispersive X-ray (EDX) analysis. The photodegradation study of BG5 showed that the dye degradation increases as a function of irradiation time. The degradation of BG5 was found to be pH dependent and maximum degradation was found at higher pH. 相似文献
96.
Influence of plasticizers and cryogenic grinding on the high‐cooling‐rate solidification behavior of PBT/PET blends 下载免费PDF全文
Anesh Manjaly Poulose Stefano Piccarolo Domenico Carbone Saeed M. Al‐Zahrani 《应用聚合物科学杂志》2016,133(10)
Two structurally different plasticizers (cyclic and linear) and the effect of cryogenic grinding on the solidification behavior at high cooling rates by a continuous cooling transformation approach of poly(butylene terephthalate)/poly(ethylene terephthalate), PBT/PET, blends are described. The solidification curve (density versus cooling rate) is confirmed as an effective tool to compare the differences in crystallization behavior under conditions mimicking processing. In comparison to the bulky cyclic plasticizer, the linear oligomeric one was found to have a more pronounced influence on the crystallization behavior. A 60/40 by weight PBT/PET blend shows a drop‐off of density at ~50 K/s. In the plasticized sample, the long‐range crystalline order appears up to a cooling rate of ~250K/s, making the blend comparable to pure PBT. Grinding the components before blending further improves crystallizability and synergy to the addition of the plasticizer. The results suggest the important role of local chain mobility in the solidification behavior at high cooling rates. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43083. 相似文献
97.
Investigation of structure and mechanical properties of toughened poly(l‐lactide)/thermoplastic poly(ester urethane) blends 下载免费PDF全文
In this study, poly(l ‐lactide) (PLA) is melt‐blended with thermoplastic polyurethane (TPU) to modify the brittleness of PLA. An aliphatic ester‐based TPU was selected in order to have an ester sensitivity for degradation and an inherent biocompatibility. Using this compatible TPU, there was no need to apply problematic compatibilizers, so the main positive properties of PLA such as biocompatibility and degradability were not challenged. The detected microstructure of PLA/TPU blends showed that when the TPU content was lower than 25 wt %, the structure appeared as sea‐islands, but when the TPU content was increased, the morphology was converted to a cocontinuous microstructure. A higher interfacial surface area in the blend with 25 wt % TPU (PLA25) resulted in a higher toughness and abrasion resistance. The various analyses confirmed interactions and successful coupling of two phases and confirmed that melt‐blending of PLA with the aliphatic ester‐based TPU is a convenient, cost‐effective, and efficient method to conquer the brittleness of PLA. The prepared blends are general‐purpose plastics, but PLA25 showed an optimum mechanical strength, toughness, and biocompatibility suitable for a wide range of applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43104. 相似文献
98.
Pari Mirahmadpour Davood Nematollahi Mohammad Hossein Banitaba Saied Saeed Hosseiny Davarani 《Journal of Inorganic and Organometallic Polymers and Materials》2016,26(2):376-383
Electrochemical synthesis of coordination polymers of Cu(II), [Cu(TDA)]n and [Cu2(BTC)(H2O)6?6H2O]n in which H2TDA is 2,2′-thiodiacetic acid and BTC stands for 1,2,4,5-benzenetetracarboxylate was carried out by the electrochemical oxidation of Cu anode in the presence of H2TDA (a flexible ligand), and 1,2,4,5-benzentetracarboxylic acid (H4BTC) (a rigid ligand) in aqueous solutions. The structure of coordination polymers were characterized by scanning electron microscopy, X-ray powder diffraction, elemental analysis, thermal gravimetric and differential thermal analyses. The crystal structure of the compounds consists of one-dimensional cubical crystal polymeric units of [Cu(TDA)]n and [Cu2(BTC)(H2O)6?6H2O]n. Furthermore, the coordination number of Cu (II) ions in synthesized coordination polymers to be found five. The main advantages of electrosynthesis are the minor synthesis time, the milder conditions and the facile synthesis of coordination polymer coatings. 相似文献
99.
Synthesis and Spark Plasma Sintering of Mg2Si Nanopowder by Mechanical Alloying and Heat Treatment 下载免费PDF全文
Mohammad Khajelakzay Saeed Reza Bakhshi Gholam Hossein Borhani Mazaher Ramazani 《International Journal of Applied Ceramic Technology》2016,13(3):498-505
In this investigation, a two‐step method for the preparation of magnesium silicide (Mg2Si) nanopowder was studied. This method is known as mechanical alloying followed by heat treatment. The results showed that the compositions of the combustion products depended on the milling time, heat treatment temperature, and starting mixtures. Pure Mg2Si nanopowder was formed after short milling time and heat treatment, from Mg and Si powders with the mole ratio of 2.1:1 (Mg:Si) at 500°C in Ar atmosphere. Using the Mg2Si nanopowder, Mg2Si ceramic was produced by spark plasma sintering at 800°C under 50 MPa for 15 min. Composition and structure of reactants and products were examined by X‐ray diffraction (XRD), field emission scanning electron microscopy (FE‐SEM) and high‐resolution transmission electron microscopy (HR‐TEM). 相似文献
100.
In this study, glass flakes were incorporated into the spherical nanosilica component of the dental composites and its effect on the mechanical properties of these composites was investigated. To achieve a good interfacial adhesion between matrix resin and fillers, the particles were surface treated with a silane coupling agent (γ-MPS). Composites with different plate-like and spherical nanoparticle contents were prepared and their mechanical properties, including flexural strength, flexural modulus and fracture toughness were measured. The morphology of the particles and fracture surface of the composites were studied by SEM. The distribution of the flakes in the composite was also monitored using EDXA. Statistical analysis of the data was performed with ANOVA and the Tukey’s post hoc test was at a significance level of 0.05. The results showed that the flexural modulus and fracture toughness of specimens were improved with increasing the glass flake content up to 15 vol % which then declined upon further increase due to the stacking of the flakes on each other. A good interfacial adhesion was observed between matrix resin and particles in the SEM micrographs. The results of this study suggest that incorporation of glass flakes into the dental composites containing spherical nanosilica particles may enhance their mechanical properties. 相似文献