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1.
《Arabian Journal of Chemistry》2022,15(9):104086
In this paper, we studied commercially available precipitated rice husk silica (RHS) with conventional precipitated silica, which has nearly the same surface area, and replaced part of the carbon black with RHS and conventional silica in a basic tread formulation. All formulations were mixed with the same amount of filler during the study. Silica was used at 15, 30 and 50 phr loading, and part of the carbon black was replaced by silica. Compound curing characteristics, physical properties, rebound resilience, heat generation, abrasion loss, dynamic properties and morphology were analyzed. The results indicated that RHS demonstrated compound properties comparable to those of conventional silica. As part of the carbon black was replaced with conventional silica, a slower cure rate, higher rebound resilience, lower heat generation, lower abrasion loss, and lower tan delta were observed with no significant change in physical properties, but some changes in physical properties were observed using one way ANOVA analysis. We found the same trend when replacing part of the carbon black with RHS, such as a slower cure rate, higher rebound resilience, lower heat generation, lower abrasion loss, and lower tan delta with no significant change in physical properties, but some changes in physical properties were observed using one way ANOVA. This sustainable material could be used to replace conventional silica in tire compounding, as well as to replace a portion of carbon black with RHS for improved heat build-up, rolling resistance, and abrasion loss. 相似文献
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Ab initio molecular orbital theory including full geometry optimization at the 4-31G level is used to examine the interactions between substitutents X(X = Li, BeH, BH2, CH3, NH2, OH and F) and substrates Y(Y = NH3+, CH3, BH3?) in the isoelectronic series XNH3+, XCH3 and XBH3?. The results indicate that the interaction energies are dominated by σ-effects. NH3+ is found to interact favorably with the σ-donors (e.g. Li, BeH and BH2) and unfavorably with the σ-acceptors (e.g. F, OH, NH2). The reverse pattern a observed for XBH3?. The range of interaction energies for XCH3 is considerably smaller than for XNH3+ and XBH3?. 相似文献
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Alkaline-earth (Ae) metals have attracted a wealth of interdependent research from synthetic chemists. In Ae-catalyzed organometallic reactions, β-diketiminate is a typical ligand used to stabilize Ae catalysts by forming six-membered rings comprising Ae metals. Herein, studies focusing on the configuration of β-diketiminate-coordinated Ae compounds observed that the CC and CN bonds are homogeneous and unchanged. Furthermore, energetic studies observed that the formation of the Ae-incorporated six-membered rings results in enhanced stability of >20 kcal/mol. The nucleus-independent chemical shifts, anisotropy of the induced current density, and molecular orbital analyses demonstrated the non-aromaticity of the β-diketiminate-coordinated Ae compounds. The improved stability of these compounds can be explained by the delocalization of the π electrons derived from the β-diketiminate moiety. 相似文献
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I.J. Galpin F.E. Hancock B.K. Handa A.G. Jackson G.W. Kenner P. McDowell P. Noble R. Ramage 《Tetrahedron》1981,37(17):3043-3050
The previously synthesised (1–37), (38–75), (76–93), (94–104), (105–117) and (118–129) fragments of the analogue were combined making extensive use of the DCCI/HONSu method. The final coupling involved the (1–75) and (76–129) sub-fragments. Aggregation of the latter fragment caused problems in purification by routine gel filtration methods employing Enzacryl K2 or Sephadex LH60. The fully protected (1–129) product was partially purified by washing, then deprotectcd and purified by gel filtration and ion exchange chromatography. Satisfactory removal of the acetamidomethyl group used for cysteine protection could not be achieved. 相似文献
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An universal function for non-bonded interactions, which takes into account the relative orientation of the bonds is considered in calculating the conformational energies of cycloalkenes and cycloalkadienes. A comparison is made with previous results obtained by using usual 6-exp functions for non-bonded interactions. 相似文献