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The molecular origin of the demixing behavior for 50: 50 (wt/wt) polyethylene/polypropylene (PE/PP) with different tacticity of PP at the melts (473 K) was investigated by Monte Carlo simulation of coarse-grained polymer model. Isotactic (iPP), atactic (aPP) and syndiotactic (sPP) polypropylenes were used for blending with PE. Coarse-graining polymer chains were represented by 50 beads, corresponding to C100H202 and C150H302 for PE and PP, respectively. The simulation was performed on a high coordination lattice incorporating short-range intramolecular interactions from the Rotational Isomeric State (RIS) model and long-range intermolecular interactions Lennard-Jones (LJ) potential function of ethane and propane units. Chain dimensions, the characteristic ratio (C n ) and self-diffusion coefficient (D) of PE in the blends are sensitive to the stereochemistry of PP chains. Compared with neat PE melts, PE dimension was relatively unchanged in PE/iPP and PE/aPP blends but slightly decreased in PE/sPP blends. PP dimension was increased in PE/iPP and PE/aPP mixture but decreased in PE/sPP blend in comparison with neat PP melts. In addition, diffusion of PE and PP chains in PE/PP mixture was decreased and increased, respectively, compared to the pure melts. Interchain pair correlation functions were used to detect the immiscibility of the blends. The tendency of demixing of PE/aPP and PE/iPP blends were weaker than that of PE/sPP blend. 相似文献
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Adisak Thanetchaiyakup Hassayaporn Rattanarat Nutthawat Chuanopparat Paiboon Ngernmeesri 《Tetrahedron letters》2018,59(11):1014-1018
A simple and efficient one-pot synthesis of substituted indolo[1,2-a]quinolines under transition-metal-free conditions has been developed. When 2-fluorobenzaldehyde was treated with substituted 2-methylindoles in the presence of Cs2CO3, the desired products were typically obtained in good to excellent yields. This reaction sequence involves a nucleophilic aromatic substitution and a Knoevenagel condensation reaction. Our mechanistic investigation revealed that both reactions could proceed as an intermolecular reaction in the first step. 相似文献
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Decarbonylative Silylation of Esters by Combined Nickel and Copper Catalysis for the Synthesis of Arylsilanes and Heteroarylsilanes 下载免费PDF全文
M. Sc. Lin Guo M. Sc. Adisak Chatupheeraphat Prof. Dr. Magnus Rueping 《Angewandte Chemie (International ed. in English)》2016,55(39):11810-11813
An efficient nickel/copper‐catalyzed decarbonylative silylation reaction of carboxylic acid esters with silylboranes is described. This reaction provides access to structurally diverse silanes with high efficiency and excellent functional‐group tolerance starting from readily available esters. 相似文献
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Asymmetric Brønsted Acid Catalyzed Substitution of Diaryl Methanols with Thiols and Alcohols for the Synthesis of Chiral Thioethers and Ethers 下载免费PDF全文
Adisak Chatupheeraphat Hsuan‐Hung Liao Steffen Mader Makoto Sako Prof. Dr. Hiroaki Sasai Dr. Iuliana Atodiresei Prof. Dr. Magnus Rueping 《Angewandte Chemie (International ed. in English)》2016,55(15):4803-4807
An enantioselective addition of thiols and alcohols to aza‐ortho‐quinone methides, starting from diaryl methanols, was developed. The asymmetric additions occur under mild reaction conditions in the presence of chiral phosphoric acids and furnish the corresponding adducts with excellent yields and enantioselectivities. 相似文献
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Adisak Jaturapiree Anelise Ehrhardt Sibylle Groner Hale Bahar Öztürk Barbora Siroka Thomas Bechtold 《Macromolecular Symposia》2008,262(1):39-49
Of prime importance in reactions involving insoluble cellulosic fibers is the sorption of reagents, which is governed by their degrees of accessibility in substrates. Swelling treatments of cellulosics in alkali solutions alter substrate accessibility leading to changes in their reactivity. In this paper, the first of a two-part series, we collate and examine the results from various studies involving different techniques to characterize modifications in cellulosic fibers after swelling treatments in alkali solutions. Results from measurements of structure and accessibility in fibers with techniques such as water retention, inverse size exclusion chromatography (ISEC), iodine sorption, fiber diameters, and fiber-splitting propensities indicate that the influence of swelling treatments on fiber structure/accessibility is differs with alkali type. The results show that a non-uniform rather than uniform distribution of reagents within structures is a more accurate representation of reactions involving swollen cellulosic fibers. Hence, the observed changes in cellulose-fiber reactivity are governed by the degrees of fiber swelling, and reagent sorption and accessibility during swelling treatments. 相似文献
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The high concentration and uniform distribution of diamond particles in Ni‐diamond composite coatings by sediment co‐deposition 下载免费PDF全文
Jiaqian Qin Xinyu Zhang Yannan Xue Malay Kumar Das Adisak Thueploy Sarintorn Limpanart Yuttanant Boonyongmaneerat Mingzhen Ma Riping Liu 《Surface and interface analysis : SIA》2015,47(3):331-339
Ni‐diamond composite coatings with high concentration and uniform distribution of diamond particles were prepared by using sediment co‐deposition (SCD) technique from Watts‐type electrolyte without any additives. The surface and cross‐section morphology was evaluated by optical microscope (OM) and scanning electron microscopy (SEM). It was demonstrated that the Ni‐monolayer diamond composite coatings ~40 ± 5 µm was successfully prepared by the new developed setup for SCD technique. Using this new developed setup, high concentration and uniform distribution of diamond particles of Ni‐monolayer diamond composite coatings were easily fabricated. The wear resistance and cutting performance of obtained composite coatings were also investigated. The results revealed that anti‐wear and cutting performance is superior to those prepared via conventional co‐electrodeposition (CED) technique and pure Ni coatings. In the SCD process, with the increasing diamond content, the wear resistance is approximately the same, and the cutting performance decreases. Therefore, not only the diamond particle content is responsible for the wear resistance and cutting performance, the distribution of diamond particles is also very important factor. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Numerical Algorithms - Our contribution in this paper, we introduce and analyze two new hybrid algorithms by combining Mann iteration and inertial method for solving split fixed point problems of... 相似文献
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Adisak Jaturapiree Avinash P. Manian Thomas Bechtold 《Cellulose (London, England)》2006,13(6):647-654
The degrees of salt sorption were determined in lyocell and viscose fibers immersed in aqueous solutions of salt–alkali mixtures with the aim of using salt sorption as an indirect measure of changes to fiber accessibility in presence of alkali. The salt–alkali mixtures used were combinations of NaOH with NaCl or NaBr, and of KOH with KCl or KBr. In general, salt sorption in fibers increased with increase in alkali concentration up to 2 mol/l, and did not change significantly thereafter. The accessibility of Br− salts was greater than the Cl− salts, but that of the Na+ salts was greater than the K+ salts. These trends in salt sorption indicate that salt accessibility in fibers is not influenced by the size of hydrated salt ions, but by the forces of electrostatic attraction and repulsion between the charged fiber surface and salt cations and anions. 相似文献