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1.
J. -M. Douillard H. Malandrini T. Zoungrana F. Clauss S. Partyka 《Journal of Thermal Analysis and Calorimetry》1994,41(6):1205-1210
It is possible to estimate surface tension of high-energy solids combining the immersion microcalorimetry thermodynamics and Van Oss' model. In this study we have applied this method on talc and talc-chlorite samples in order to obtain thermodynamic values which permit to understand surface properties useful in the industrial applications of these solids. Some talcite samples are preferentially used in specific industrial applications because they are less hydrophobic or more lamellar. This method seems to be reliable to classify the solids and predict some properties. 相似文献
2.
V. Balek L. A. Pérez-Maqueda J. Poyato Z. Černý V. Ramírez-Valle I. M. Buntseva J. L. Pérez-Rodríguez 《Journal of Thermal Analysis and Calorimetry》2007,88(1):87-91
The effect of grinding
on thermal behavior of pyrophyllite and talc as commonly used ceramic clay
minerals was investigated by DTA, TG, emanation thermal analysis (ETA), B.E.T.
surface area (s.a.) measurements, X-ray diffraction (XRD) and scanning electron
microscopy (SEM).
A vibratory mill was used in this study, grinding
time was 5 min. It was found that the grinding caused an increase in surface
area and a grain size reduction of the samples. From TG and DTA results it
followed that grinding caused a decrease of the temperature at which the structure
bound OH groups released. The formation of high temperature phases was enhanced
with the ground samples. For the ground talc sample the crystallization of
non-crystalline phase into orthorhombic enstatite was observed in the range
of 800°C. For ground pyrophyllite a certain agglomeration of grains was
observed in the range above 950°C. Moreover, for both clays the ETA characterized
a closing up of subsurface irregularities caused by grinding as a decrease
of the emanation rate in the range 250–400°C. The comparison of
thermal analysis results with the results of other methods made it possible
to better understand the effect of grinding on the ceramic clays. 相似文献
3.
An Huang Peng Yu Xin Jing Hao-Yang Mi Li-Hong Geng 《Journal of Macromolecular Science: Physics》2016,55(9):908-924
Poly(lactic acid) (PLA)/talc composites containing different contents of talc were prepared by melt blending. Multiple properties of the prepared composites were investigated including mechanical, rheological and crystallization as well as foaming properties. Tensile test results indicated that the mechanical properties of the composite with 3% wt. talc showed significant reinforcement and toughening effect. When the talc content reached 10%, Young's modulus of the composite was increased by 35% compared with pure PLA. The morphological results showed that the talc layers were partially delaminated and uniformly dispersed in the PLA matrix at low loading. Differential scanning calorimetry (DSC) and polarized optical microscopy (POM) results indicated that 3% wt. talc significantly increased the crystallinity of the PLA matrix. The thermogravimetric analysis (TGA) results demonstrated that the thermal stability of PLA/talc composites was enhanced as well. Moreover, talc at low loading could act as a plasticizer in the polymer flow, which was investigated by rheological tests. The batch foaming experiments revealed that 3% wt. talc loading had the most notable heterogeneous nucleation effect, with the cell size decreasing from 15.4 μm for neat PLA to 8.5 μm and the cell density increasing by 298%. 相似文献
4.
Cover Picture: Fast‐Geomimicking using Chemistry in Supercritical Water (Angew. Chem. Int. Ed. 34/2016)
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5.
Polypropylene (PP) constituted 30% of the collected material in a Swedish collection system for rigid plastic packaging waste. The PP fraction was however a complex mixture of grades with widely different properties. In order to enhance the rigidity of the recycled PP, modified grades were prepared by compounding with talc and/or a virgin high‐crystallinity PP grade. Adding 20–40% of high‐crystallinity PP enhanced the stiffness and yield strength without impairing the impact resistance. A composite material consisting of 20% of this grade, 20% talc and 60% recycled PP gave mechanical properties similar to those of a commercial talc‐filled PP compound used for demanding engineering applications. The present study demonstrates that recycled PP derived from post‐consumer packaging waste can also be made useful for demanding engineering applications. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
6.
The blends of EVA filled with talc, calcium carbonate, and glass ball (GB) have been photocrosslinked by UV irradiation in the presence of benzophenone (BP) as a photoinitiator and triallyl isocyanurate (TAIC) as a crosslinker. The various factors affecting the crosslinking process and the related properties have been studied by gel determination, heat extension test, mechanical and thermal aging test, UV spectroscopy, and scanning electron microscopy. The results show that the EVA/talc, EVA/CaCO3, and EVA/GB samples of 1 mm thickness filled with 25 phr inorganic filler can be photocrosslinked to gel content of above 70 wt% by 5 sec UV‐irradiation under optimum conditions, which is sufficient for some applications of EVA blend materials. The crosslinking rate and final gel content level are in the order of EVA/GB > EVA/talc > EVA/CaCO3. The data from mechanical and thermal aging tests give evidence that the photocrosslinked EVA/talc, EVA/CaCO3, and EVA/GB samples are of much better tensile strength and thermal aging properties than those of the unphotocrosslinked ones. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
7.
Dr. Agnieszka Swiderska-Mocek Izabela Karczewska Dr. Agnieszka Gabryelczyk Dr. Mikołaj Popławski Prof. Dr. Dorota Czarnecka-Komorowska 《Chemphyschem》2023,24(20):e202300090
A gel polymer electrolyte based on poly(vinyl alcohol) (PVA) is used in sodium-ion batteries (SIBs). The use of biodegradable and water-soluble polymer potentially reduces the negative environmental impact. The other components include sodium salt (NaPF6), sulfolane (TMS) as a plasticizer and talc. For the first time, natural and abundant talc has been used as an inert filler in a gel polymer electrolyte. The best results were obtained for moderate amounts of filler (1 and 3 wt%). Then, an increase in the conductivity, transference numbers, and thermal stability of the membranes was observed. Moreover, the presence of talc had a positive effect on the cyclability of the hard carbon electrode. The discharge capacity after 50 cycles of HC|1 % T_TMS|Na and HC|3 % T_TMS|Na was 243 and 225 mAh g−1, respectively. The use of talc in gel polymer electrolytes containing sodium ions improves the safety and efficiency of SIBs. 相似文献
8.
Based on molecular dynamics simulations, we have studied the wetting behaviors of water on the talc-like surface with different surface polarity by modifying the charge distribution of surface hydroxyl (–OH) groups. With the change of the charge of the hydrogen atom (denoted as δq) in –OH group, the contact angle decreases from 91° to 50° and then remains constant. On the surfaces with the larger charge of hydrogen atoms (δq ≥ 0.2 e), a water droplet is formed above a water monolayer, which is exactly contacted on the surface. Each water molecule in the monolayer forms one hydrogen bond (H bond) with surface –OH groups, without participating in any H bond with the water molecules within the monolayer or with the water molecules above the monolayer. The polarity of the –OH group also has a great influence on the dynamic behaviors of the interface water, such as residence time, hydrogen bond lifetime and self-diffusion coefficient. The diffusion of water molecules in the water monolayer near the highly polar surface is greatly suppressed, and the residence time of water molecules in the water monolayer even exceeds 12 ns. 相似文献
9.
Thermoplastic composites reinforced with natural fibers have attracted the attention of many researchers, not only for environmental concerns, but also for economic reasons, recyclability, ease of processing, etc. One promising application is in the automotive industry due to their low cost and weight. This industry is increasingly pressured to produce vehicles that consume less fuel and are less polluting. Therefore, plastics reinforced with fibers are required to produce lighter parts to replace the much more abrasive glass fiber and mineral filled composites. One of the most widely used polymers in the automotive sector for manufacturing interior and exterior vehicle components is talc filled EPDM (ethylene-propylene-diene monomer) toughened polypropylene (PP). In this context, the aim of this study was to assess mechanical and thermal properties of bamboo fiber reinforced recycled talc filled PP/EPDM composites compatibilized with maleic anhydride grafted polypropylene (PP-g-MAH). Composites were prepared, according to a 22 factorial design with center point, in a Haake twin screw extruder with subsequent injection molding. Injected specimens were subjected to tensile, flexural, impact and fatigue testing. Morphological analyses were performed by scanning electron microscopy (SEM), and thermal analyses by thermogravimetry (TGA) and differential scanning calorimetry (DSC). Addition of bamboo fiber significantly increased tensile and bending strength, modulus and fatigue life, and decreased elongation at break and impact strength. On the other hand, addition of the compatibilizer had a positive effect only on tensile and flexural strength, and fatigue life whereas the effect was negative on elongation at break and impact strength. The addition of fiber and compatibilizer did not appreciably affect the matrix melting temperature, but slightly increased crystallization temperature and in some cases the degree of crystallinity. 相似文献
10.
Zhenhong Liu Jingjiang Wang Haining Na Xiaoyan Yuan 《Journal of Macromolecular Science: Physics》2013,52(3):484-492
Composites of polyamide 66 (PA66)/maleic anhydride grafted poly(ethylene-co-octene) (POE-g-MAH)/nano-calcium carbonate (nano-CaCO3) and PA66/POE-g-MAH/talc were prepared by a one-step blending method. Morphology, crystallization, and mechanical properties of the composite materials were characterized with respect to different amounts of both inorganic fillers, nano-CaCO3 and talc. Results showed that the tensile yield strength and tensile modulus of the composites were increased remarkably with introduction of nano-CaCO3 or talc, but the notched impact strength was significantly lowered for both kinds of composites. Mechanical properties exhibited little difference between the PA66/POE-g-MAH/nano-CaCO3 and PA66/POE-g-MAH/talc composites both for the different shapes and sizes of nano-CaCO3 and the flake-like talc. Results of scanning electron microscopy exhibited agglomeration of the fillers. Differential scanning colorimetry analysis suggested that introduction of the inorganic fillers cause the crystallinity of PA66 to decrease by heterogeneous nucleation. The study provides a basic investigation on polymer/elastomer/rigid filler composites. 相似文献