We report a simple and automated headspace gas chromatographic technique for the determination of the softening point of rosin. A lumpy solid of rosin is added into a headspace vial, then an automated stepwise temperature ramping and headspace sampling was performed at each temperature stage and gas chromatography measurement. By plotting the gas chromatography signal for an impurity in rosin versus the temperature, a transition point (corresponding to the rosin softening point) was determined. The results show that the present method has a good precision (<0.76%), and good accuracy (the relative differences compared to the ring and ball method was <4.0%). The present method is simple, accurate, and automated. It is practical and suitable for testing the softening of rosin and derivatives in mills.
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http://dx.doi.org/10.1002/jssc.201800354 | DOI Listing |
Curr Drug Deliv
January 2025
Department of Pharmaceutical Sciences, School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
Background: Hot-melt Pressure-sensitive Adhesives (HMPSA) are eco-friendly pressuresensitive adhesives, with the potential of being used as substrates for transdermal patches. However, due to the low hydrophilicity of HMPSA, the application is limited in the field of Traditional Chinese Medicine (TCM) plasters.
Methods: Three modified HMPSA were prepared with acrylic resin EPO, acrylic resin RL100, and Polyvinylpyrrolidone (PVP) as the modifying materials.
Phys Chem Chem Phys
January 2025
School of Physics and Electronics, Hunan University, Changsha 410082, China.
Two-dimensional (2D) Janus structures with the breaking of out-of-plane mirror symmetry can induce many interesting physical phenomena, and have attracted widespread attention. Herein, we propose a MoPS monolayer with mirror asymmetry, identified by first-principles structural search calculations, which demonstrates high thermodynamic and dynamic stability. Our findings reveal that Mo 4d-orbitals dominate the metallicity, significantly enhancing the density of states near the Fermi level due to Van Hove singularities (VHSs), leading to the existence of phonon-mediated superconductivity.
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January 2025
College of Engineering, Zhejiang Normal University, Jinhua 321004, China.
Asphalt pavement, widely utilized in transportation infrastructure due to its favourable properties, faces significant degradation from chloride salt erosion in coastal areas and winter deicing regions. In this study, two commonly used asphalt binders, 70# base asphalt and SBS (Styrene-Butadiene-Styrene)-modified asphalt, were utilized to study the chloride salt erosion effect on asphalt pavement by immersing materials in laboratory-prepared chloride salt solutions. The conventional properties and adhesion of asphalt were assessed using penetration, softening point, ductility, and pull-off tests, while Fourier transform infrared spectroscopy (FTIR) elucidated the erosion mechanism.
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December 2024
School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023, China.
Copper matrix composites (Cu-MCs) have garnered significant attention due to their exceptional electrical, wear-resistant, and mechanical properties. Among them, AlO/Cu composites, reinforced with AlO, are a focal point in the field of high-strength, high-conductivity copper alloys, owing to their high strength, excellent electrical conductivity, and superior resistance to high-temperature softening. Cold deformation is an effective method for enhancing the mechanical properties of AlO/Cu composites.
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December 2024
School of Physics and School of Materials Science and Engineering, Central South University, Changsha 410083, China.
In order to investigate the effects of the softening point, the addition ratio, and the median particle size (D50) of the asphalt on the performance of secondary particles of artificial graphite anode materials prepared by granulation, ten-kilogram orthogonal experiments were designed. D50 and powder orientation index (OI) value of the prepared secondary particles of artificial graphite anode materials were employed as evaluation index, and the results of the orthogonal experiments were subjected to polarity analysis, analysis of variance (ANOVA), and multiple linear regression analysis. It is demonstrated that the addition ratio of the asphalt exerts the most pronounced influence on D50 and powder OI value of secondary granular artificial graphite anode materials, followed by the softening point.
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