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Synthesis of polystyrene-styrene/butadiene diblock copolymers via reversible addition-fragmentation chain transfer miniemulsion polymerization 被引量:3
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作者 Zhen Xi Wang Qing Hua Zhang +3 位作者 Yi Tao Yu Xiao Li Zhan Feng Qiu Chen Ji Hai Xiong 《Chinese Chemical Letters》 SCIE CAS CSCD 2010年第12期1497-1500,共4页
Polystyrene-styrene/butadiene diblock copolymers were synthesized via reversible addition-fragmentation chain transfer (RAFT) miniemulsion polymerization.During the polymerization process,the molecular weight distri... Polystyrene-styrene/butadiene diblock copolymers were synthesized via reversible addition-fragmentation chain transfer (RAFT) miniemulsion polymerization.During the polymerization process,the molecular weight distribution was narrow and the numerical molecular weight of the copolymers increased with increasing conversion of monomers,which was close to the theoretical.FT-IR and ^1H NMR results indicated that the microstructure of the polymer was mainly 1,4-trans-butadiene with small amount of 1,2-units,and composition in the copolymers was obtained. 展开更多
关键词 Reversible addition-fragmentation chain transfer Polystyrene-styrene/butadiene diblock copolymers Miniemulsion polymerization
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Phase equilibrium data prediction and process optimizationin butadiene extraction process
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作者 Baowei Niu Yanjie Yi +5 位作者 Yuwen Wei Fuzhen Zhang Lili Wang Li Xia Xiaoyan Sun Shuguang Xiang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第7期1-12,共12页
In response to the lack of reliable physical parameters in the process simulation of the butadiene extraction,a large amount of phase equilibrium data were collected in the context of the actual process of butadiene p... In response to the lack of reliable physical parameters in the process simulation of the butadiene extraction,a large amount of phase equilibrium data were collected in the context of the actual process of butadiene production by acetonitrile.The accuracy of five prediction methods,UNIFAC(UNIQUAC Functional-group Activity Coefficients),UNIFAC-LL,UNIFAC-LBY,UNIFAC-DMD and COSMO-RS,applied to the butadiene extraction process was verified using partial phase equilibrium data.The results showed that the UNIFAC-DMD method had the highest accuracy in predicting phase equilibrium data for the missing system.COSMO-RS-predicted multiple systems showed good accuracy,and a large number of missing phase equilibrium data were estimated using the UNIFAC-DMD method and COSMO-RS method.The predicted phase equilibrium data were checked for consistency.The NRTL-RK(non-Random Two Liquid-Redlich-Kwong Equation of State)and UNIQUAC thermodynamic models were used to correlate the phase equilibrium data.Industrial device simulations were used to verify the accuracy of the thermodynamic model applied to the butadiene extraction process.The simulation results showed that the average deviations of the simulated results using the correlated thermodynamic model from the actual values were less than 2%compared to that using the commercial simulation software,Aspen Plus and its database.The average deviation was much smaller than that of the simulations using the Aspen Plus database(>10%),indicating that the obtained phase equilibrium data are highly accurate and reliable.The best phase equilibrium data and thermodynamic model parameters for butadiene extraction are provided.This improves the accuracy and reliability of the design,optimization and control of the process,and provides a basis and guarantee for developing a more environmentally friendly and economical butadiene extraction process. 展开更多
关键词 butadiene extraction Phase equilibrium data Prediction methods Thermodynamic modeling Process simulation
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Synthesis and characterization of miktoarm star copolymer of styrene and butadiene using multifunctional macromolecular initiator 被引量:2
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作者 Hai Yan Zhang Xing Ying Zhang 《Chinese Chemical Letters》 SCIE CAS CSCD 2009年第9期1131-1135,共5页
A new kind of multifunctional macromolecular initiator with Sn-C bonds and polydiene arms was synthesized by living anionic polymerization. At first, polydiene-stannum chloride (PD-SnCl3) was prepared by the reactio... A new kind of multifunctional macromolecular initiator with Sn-C bonds and polydiene arms was synthesized by living anionic polymerization. At first, polydiene-stannum chloride (PD-SnCl3) was prepared by the reaction of n-butyl-Li (n-BuLi), stannic chloride (SnCl4) and diene. Then PD-SnCl3 was used to react with the dilithium initiator to prepare the multifunctional organic macromolecular initiators. The result suggested that the initiators had a remarkable yield by GPC, nearly 90%. By using these multifunctional macromolecular initiators, styrene and butadiene were effectively polymefized via anionic polymerization, which gave birth to novel miktoarm star copolymers. The relative molecular weight and polydispersity index, microstructure contents, copolymerization components, glass transition temperature (Tg) and morphology of the miktoarm star copolymers were investigated by GPC-UV, ~H NMR, DSC and TEM, respectively. 2009 Xing Ying Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. 展开更多
关键词 Mnitifunctional macromolecular initiator Miktoarm star copolymer styrene butadiene ISOPRENE Anionic polymerization
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Styrene/Butadiene Copolymer Synthesized by Reactive Extrusion 被引量:1
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作者 Ji-ming Wang Bo Chen +2 位作者 Sheng-jie Tang Dong Shan 郑安呐 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2015年第8期1096-1103,共8页
In this study, we present a method to synthesize styrene-butadiene copolymer, using anionic polymerization in a co-rotating closely intermeshing twin-screw extruder. The weight content of polybutadiene in these copoly... In this study, we present a method to synthesize styrene-butadiene copolymer, using anionic polymerization in a co-rotating closely intermeshing twin-screw extruder. The weight content of polybutadiene in these copolymers was above 50% although in the past studies it had been possible to accomplish levels higher than 30%. ^1H-NMR and GPC show that the molecular structure of the two polymers is different due to different feeding method. In terms of the structure of the polymerized products, the mechanism of polymerization in the bulk polymerization is discussed. TEM and DMA show that two phases in the block copolymer are completely incompatible, leading to sharp phase separation, while the case is complicated in the copolymer through the mixture feeding. Traditionally, styrene-butadiene rubber is mainly synthesized by solution polymerization. Reactive extrusion in this paper provides a possibility to synthesize these products in an environmentally friendly way. 展开更多
关键词 Reactive extrusion styrene butadiene Anionic polymerization.
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Study of Mechanical and Physical Properties of Palm Fiber Reinforced Acrylonitrile Butadiene Styrene Composite 被引量:2
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作者 Budrun Neher Md. Mahbubur Rahman Bhuiyan +3 位作者 Humayun Kabir Md. Rakibul Qadir Md. Abdul Gafur Farid Ahmed 《Materials Sciences and Applications》 2014年第1期39-45,共7页
Palm fiber (PF) reinforced acrylonitrile butadiene styrene (ABS) composite matrix was prepared by employing Injection Moulding Machine (IMM). Palm fiber was collected from ten different trees of different age group fr... Palm fiber (PF) reinforced acrylonitrile butadiene styrene (ABS) composite matrix was prepared by employing Injection Moulding Machine (IMM). Palm fiber was collected from ten different trees of different age group from Comilla region in Bangladesh. Three sets of samples were prepared for three different wt% (5%, 10% and 20%) of fiber contents. The mechanical (tensile strength, flexural stress, micro hardness, Leeb’s rebound hardness) and physical (bulk density and water absorption) properties were measured. The observed result reveals that the tensile strength (TS) and flexural stress (FS) were decreased with increasing fiber contents in the PF-ABS composites except 10% fiber content. 展开更多
关键词 Acrylonitrile butadiene styrene COMPOSITE Tensile STRESS Flexural STRESS Vicker’s HARDNESS and Leeb’s REBOUND HARDNESS
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Study of microstructure and flexural properties of microcellular acrylonitrile-butadiene-styrene nanocomposite foams: experimental results 被引量:3
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作者 A.MOHYEDDIN A.FEREIDOON I.TARAGHI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2015年第4期487-498,共12页
In this paper, acrylonitrile-butadiene-styrene (ABS) nanocomposite foams are produced using carbon dioxide through the solid-state batch process. Microcellular closed-cell foams are produced with the relative densit... In this paper, acrylonitrile-butadiene-styrene (ABS) nanocomposite foams are produced using carbon dioxide through the solid-state batch process. Microcellular closed-cell foams are produced with the relative density ranging from 0.38 to 0.97. The effects of the processing conditions on the density, morphology, and flexural properties of ABS and its nanocomposite foams are studied. It is found that nanoclay particles, as nucleating sites, play an important role in reducing the size of cells and increasing their number in the unit volume of foamed polymer, as well as increasing the flexural modulus of foam through reinforcing its matrix. 展开更多
关键词 acrylonitrile-butadiene-styrene (ABS) polymer-clay nanocomposite mi-crocellular foam flexural property
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The Effects of Build Parameters and Strain Rate on the Mechanical Properties of FDM 3D-Printed Acrylonitrile Butadiene Styrene 被引量:1
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作者 Kemar Hibbert Grant Warner +3 位作者 Celeste Brown Olusegun Ajide Gbadebo Owolabi Amin Azimi 《Open Journal of Organic Polymer Materials》 2019年第1期1-27,共27页
In this paper, the effects of build parameters on the mechanical properties of 3D-printed acrylonitrile butadiene styrene (ABS) produced using fused deposition modeling (FDM) are investigated. Full factorial experimen... In this paper, the effects of build parameters on the mechanical properties of 3D-printed acrylonitrile butadiene styrene (ABS) produced using fused deposition modeling (FDM) are investigated. Full factorial experimental design incorporating a 2-level, 3-factor design with raster angle, layer thickness and interior fill style was carried out. Tensile tests were performed at four different strain rates to determine how the build parameters influence the mechanical properties of the 3-D printed ABS and to assess its strain rate sensitivity under quasi-static loading. It was found that the modulus of toughness of ABS material is most influenced by raster angle, while the interior fill style is the most dominant build parameter that dictates the specimen’s modulus of resilience, yield strength and ultimate tensile strength. At all strain rates, it is further revealed that higher mean values of yield strength, ultimate tensile strength and modulus of resilience were obtained when the interior fill style is solid as opposed to high density. This can be attributed to the denser structure and higher effective cross-sectional area in solid interior fill style in comparison with high density interior fill style. However, the influence of the layer thickness on the investigated mechanical properties was found to be inconsistent. It was noted that specimens built with both 0.254 mm layer thickness and the cross [0°/90°] raster angle had superior mechanical properties when compared to those built with the 0.3302 mm layer thickness and cross [0°/90°] raster angle. This suggests that there is a key interaction between the layer thickness and the raster angle. At any FDM build parameter, it was found that all the mechanical properties investigated in this work exhibited modest sensitivity to strain rates. This study has provided a platform for an appropriate selection of build parameters combinations and strain rates for additive manufacturing of 3D-printed ABS with improved mechanical properties. 展开更多
关键词 BUILD PARAMETERS MECHANICAL Properties Additive Manufacturing 3D Printing ACRYLONITRILE butadiene styrene
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Effect of Methyl Methacrylate– Acrylonitrile -Butadiene–Styrene (MABS) on the Mechanical and Thermal Properties of Poly (Methyl Methacrylate) (PMMA)-Fly Ash Cenospheres (FAC) Filled Composites 被引量:1
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作者 M. B. Kulkarni P. A. Mahanwar 《Journal of Minerals and Materials Characterization and Engineering》 2012年第4期365-383,共19页
With the advent of plastics and the wide range of fillers that are available have made modifications as precise as the tailored resins themselves. To modify the properties of polymer either by using fillers or by prep... With the advent of plastics and the wide range of fillers that are available have made modifications as precise as the tailored resins themselves. To modify the properties of polymer either by using fillers or by preparation of polymer blends gives rise to new materials with tailored properties. More complex, three-component systems, obtained by the addition of polymeric modifier to polymer filled composites may be of interest. Use of Fly ash cenospheres is very attractive because it is inexpensive and its use can reduce the environmental pollution to a significant extent. In the present study, Poly (Methyl Methacrylate) (PMMA)-Fly ash cenospheres composites were prepared using extrusion followed by Injection molding. The effect of matrix modification with Methyl methacrylate– acrylonitrile -butadiene–styrene (MABS) on the performance of PMMA- Fly ash cenospheres compositions was also, studied. It was found that with the addition of Fly ash cenospheres particulate as filler in PMMA showed marginal reduction in Tensile Strength, % Elongation and Impact strength and improvement in Flexural Strength, Heat Deflection Temperature and Vicat Softening Point. Compared with PMMA-cenospheres composites, the notched Impact Strength of the PMMA/MABS/cenospheres composites showed marginal enhancement in values at higher loading of cenospheres. The optimum performances in mechanical and thermal properties were obtained when the ratio of MABS to cenospheres was 1:2. 展开更多
关键词 Poly (Methyl Methacrylate) (PMMA) Fly ash cenospheres (FAC) Methyl methacrylate– ACRYLONITRILE -butadienestyrene (MABS) Mechanical and Thermal Properties.
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Structures and Properties Characterization of Acrylonitrile-butadiene-styrene /Organo-palygorskite Clay Composites 被引量:1
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作者 张哲 CHANG Ying +3 位作者 XU Jian WU Zhancui MA Hengchang 雷自强 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2012年第6期1068-1071,共4页
Palygorskite (PGS) and vinyl tris-(2-methoxyethoxy) silane (KH-172) modified palygorskite (OPGS) were used to prepare acrylonitrile-butadiene-styrene (ABS)/clay composites. Thermal stability of the composite... Palygorskite (PGS) and vinyl tris-(2-methoxyethoxy) silane (KH-172) modified palygorskite (OPGS) were used to prepare acrylonitrile-butadiene-styrene (ABS)/clay composites. Thermal stability of the composites was evaluated by using thermogravimetric analysis (TGA). The morphology of the fractured surface and the degree of dispersion of the clay in the ABS matrix were observed by scanning electron microscopy (SEM). X-ray diffraction (XRD) analysis results showed the variation of the crystal structure. Measurements of the tensile properties of the ABS/clay composites proved that the ABS/OPGS composited material represented the most excellent tensile property, because of good compatibility and dispersion of ABS with OPGS. 展开更多
关键词 PALYGORSKITE ACRYLONITRILE-butadiene-styrene MODIFICATION silane coupling agents COMPOSITES
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MORPHOLOGY,INTERFACIAL INTERACTION AND PROPERTIES OF STYRENE-BUTADIENE RUBBER/MODIFIED HALLOYSITE NANOTUBE NANOCOMPOSITES 被引量:1
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作者 贾德民 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2009年第6期857-864,共8页
A natural nanotubular material,halloysite nanotubes(HNTs),was introduced to prepare styrene-butadiene rubber/modified halloysite nanotube(SBR/m-HNT) nanocomposites.Complex of resorcinol and hexamethylenetetramine (RH)... A natural nanotubular material,halloysite nanotubes(HNTs),was introduced to prepare styrene-butadiene rubber/modified halloysite nanotube(SBR/m-HNT) nanocomposites.Complex of resorcinol and hexamethylenetetramine (RH) was used as the interfacial modifier.The structure,morphology and mechanical properties of SBR/m-HNT nanocomposites,especially the interfacial interactions,were investigated.SEM and TEM observations showed that RH can not only facilitate the dispersion and orientation of HNTs in SBR matrix at ... 展开更多
关键词 styrene-butadiene rubber Halloysite nanotubes Complex of resorcinol and hexamethylenetetramine NANOCOMPOSITES Hydrogen bond
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Volatile Substances in Polymer Toys Made from Butadiene and Styrene 被引量:2
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作者 Yutaka Abe Miku Yamaguchi +2 位作者 Motoh Mutsuga Hiroshi Akiyama Yoko Kawamura 《American Journal of Analytical Chemistry》 2013年第5期229-237,共9页
The residual levels and migration behavior of volatile substances were detected using HS-GC/MS for acrylonitrile-butadiene-styrene copolymer (ABS) toys, thermoplastic elastomer toys, and rubber toys made from 1,3-buta... The residual levels and migration behavior of volatile substances were detected using HS-GC/MS for acrylonitrile-butadiene-styrene copolymer (ABS) toys, thermoplastic elastomer toys, and rubber toys made from 1,3-butadiene and styrene found on the Japanese market. The maximum residual level of these volatile substances was 2600 μg/g of styrene in ABS toys. In particular, the levels of known carcinogens 1,3-butadiene, benzene, and acrylonitrile are 5.3, 2.5 and 55 μg/g, which are much lower than the EU limit of 0.1%. Furthermore, some volatile substances migrated from ABS toys into water in amounts of 3 -40 ng/mL. Thermoplastic elastomer toys and rubber toys contained these volatile substances at significantly lower levels than ABS toys. 展开更多
关键词 VOLATILE Substance TOY ACRYLONITRILE-butadiene-styrene Copolymer (ABS) Thermoplastic Elastomer Rubber
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STUDY ON STYRENE-BUTADIENE BLOCK COPOLYMER FOR THE MODIFICATI0N OF TIRE TREAD
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作者 王岩 陈伟洁 +3 位作者 穆瑞凤 王用威 余丰年 刘青 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1996年第1期34-40,共7页
This paper mainly deals with the design and synthesis of a novel styrene-butadieneblock copolymer. When this copolymer is used in the tread portion of tyres, it can improvewet skid resistance and reduce rolling resist... This paper mainly deals with the design and synthesis of a novel styrene-butadieneblock copolymer. When this copolymer is used in the tread portion of tyres, it can improvewet skid resistance and reduce rolling resistance without sacrificing its general physical-mechanical properties. The visco-elastic curve of tire tread using the novel copolymer asits rubber portion was showed. Reactivity ratios for two monomers in the polymerizingsystem were calculated. The diagrams of differelitial, integral and finite difference calculithroughout the whole molecular chain were presented. The influence of the micro- andmacro-structure of the copolymer chain on wet skid resistance and rolling resistance wasdiscussed 展开更多
关键词 Anionic solution polymerization Diblock copolymer of styrene and butadiene Rolling resistance Wet skid resistance Visco-elastic property
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Oil Gels Based on Styrene Butadiene Rubber
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作者 周美华 徐静波 Won-jei CHO 《Journal of Donghua University(English Edition)》 EI CAS 2004年第1期51-56,共6页
Four oil absorbents based on styrene butadiene (SBR), i.e., pure SBR (PS), 4. tert-butylstyrene-SBR (PBS), EPDM-SBR network (PES) and 4.tert-butylstyrene-EPDMSBR (PBES), were produced from crosslinking polymerization ... Four oil absorbents based on styrene butadiene (SBR), i.e., pure SBR (PS), 4. tert-butylstyrene-SBR (PBS), EPDM-SBR network (PES) and 4.tert-butylstyrene-EPDMSBR (PBES), were produced from crosslinking polymerization of uncured styrene butadiene rubber (SBR), 4-tert-butylstyrene (tBS) and ethylene-propylenc-diene terpolymer (EPDM). The reaction took place in toluene using benzoyl peroxide (BPO) as an initiator. Uncured SBR was used as both a pre-polymer and a crosslink agent in this work, and the crosslinked polymer was identified by IR spectroscopy. The oil absorbency of the crosslinked polymer was evaluated with the method ASTM (F726-81). The order of maximum oil absorbency was PBES>PBS>PES>PS. The maximum values of oil absorbency of PBES and PBS were 74.0g/g and 69.5g/g, respectively. Gel fractions and swelling kinetic constants, however, had the opposite sequences. The swelling kinetic constant of PS evaluated by an experimental equation was 49. 97×10^(-2)h^(-1). 展开更多
关键词 oil gel styrene butadiene rubber swelling kinetic constant
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FRACTAL CHARACTER OF PHASE MORPHOLOGY OF HIGH IMPACT POLYSTYRENE/POLY(cis-BUTADIENE) RUBBER BLENDS 被引量:1
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作者 盛京 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2006年第2期125-133,共9页
Evolution and fractal character of the phase morphology of high impact polystyrene/poly(cis-butadiene) rubber (HIPS/PcBR) blends during melting and mixing were investigated using scanning electron microscopy (SEM... Evolution and fractal character of the phase morphology of high impact polystyrene/poly(cis-butadiene) rubber (HIPS/PcBR) blends during melting and mixing were investigated using scanning electron microscopy (SEM). The characteristic length L was defined as the size of particles of the dispersed phase in blends. Different fractal dimensions, Df and Din, were introduced to study the distribution width of phase dimensions in the dimensionless region and the uniformity of the spatial distribution of particles, respectively. The results showed that the average characteristic length Lm and Df increase as the volume fraction of the dispersed phase increases, when the volume fraction of the dispersed phase is lower than 50%. In other words, the size of particles increases and their distribution in the dimensionless region becomes more uniform. Meanwhile, the uniformity of the spatial distribution becomes more perfect as the volume fraction increases. At a certain composition, Lm decreases in the initial stage of the mixing and levels off in the late stage. In the initial stage, Df becomes large rapidly with the process of blending, which means that the distribution of L in the dimensionless region becomes more uniform. Meanwhile, the spatial distribution tends to be ideal rapidly in the early stage and fluctuates in a definite range in the late stage of the mixing. 展开更多
关键词 Polymer blends High impact polystyrene Poly(cis-butadiene rubber Fractal character
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Synthesis And Properties Of Functional Ultra-High Molecular Weight Transparent Styrene-Butadiene Block Copolymer
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作者 GONG Guang-bi1, ZHAO Xu-tao1, WANG Gui-lun2 1.Petrochemical Research Institute of Lanzhou Petrochemical Corporation, PetroChina, Lanzhou 730060, China 2.Chemical & Marketing Company of PetroChina Company Limited, Beijing 100011, China 《合成化学》 CAS CSCD 2004年第z1期57-57,共1页
关键词 ANIONIC polymerization styrene-butadiene block copolymer Coupling agent MATHEMATICAL model FUNCTIONAL group
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Synthesis and performance of miktoarm star copolymers of styrene and butadiene
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作者 张海燕 可勇 +2 位作者 姚明 赵素合 张兴英 《Journal of Beijing Institute of Technology》 EI CAS 2011年第2期280-284,共5页
A novel multifunctional macromolecular organolithium initiator (PD-Sn-(RLi)3) was prepared via living anionic polymerization and used for the synthesis of miktoarm star copolymers in cyclohexane. The average molec... A novel multifunctional macromolecular organolithium initiator (PD-Sn-(RLi)3) was prepared via living anionic polymerization and used for the synthesis of miktoarm star copolymers in cyclohexane. The average molecular weight, polydispersity index, microstructure and unit composition of the miktoarm star copolymers were characterized with GPC and 1H-NMR. Performances of the miktoarm star styrene-butadiene rubbers were investigated in comparison with those of the blend rubbers such as the tin-coupled star-shaped random copolymers of styrene-butadiene rubber(S-SBR)/natural rubber (NR) blend rubber and S-SBR/Cis-1, 4-polybutadiene rubber (Cis-BR) blend rubber. 展开更多
关键词 anionic polymerization multifunctional macromolecular organolithium initiator miktoarm star copolymer styrene-butadiene rubber
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Fabrication and Characterization of Poly(Styrene-Butadiene-Styrene)/Thermoplastic Polyurethane Blends
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作者 Yuhsin Tsai Mu-Chen Kuo Jyh-Horng Wu 《Journal of Materials Science and Chemical Engineering》 2021年第2期1-10,共10页
This investigation presents thermoplastic elastomers (TPEs) based on poly (styrene-butadiene-styrene) (SBS) and thermoplastic polyurethane (TPU) materials were prepared with varying compositions. A series of works wer... This investigation presents thermoplastic elastomers (TPEs) based on poly (styrene-butadiene-styrene) (SBS) and thermoplastic polyurethane (TPU) materials were prepared with varying compositions. A series of works were conducted on the relationships between rheological, optical properties, morphology, mechanical properties, abrasion resistance and thermostability given. The results showed that the shear viscosity of SBS not obvious effect with TPU content. The optical properties of the SBS/TPU blend that its uniform transparency. The morphology characteristics indicating the phase diversion and the variation in the size of the SBS domains from large to small as the TPU contents increased, with heterogeneous domain dispersions. Additionally, the mechanical properties, abrasion resistance and thermal resistance are improved as the amount of added TPU is increased, suggesting that the blending of SBS with TPU is consistent with the compound rule. 展开更多
关键词 Thermoplastic Elastomers Poly(styrene-butadiene-styrene) Thermoplastic Polyurethane
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Thermal Stability Improvement and Structural Change of Oil Gels Formed by Styrene-Butadiene-Styrene Triblock Copolymer Induced by Adding Poly(phenylene ether)
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作者 Kouichi Kato Yuki Tsukamoto +2 位作者 Eri Hirai Yasuhiro Matsuda Shigeru Tasaka 《Open Journal of Organic Polymer Materials》 2014年第4期65-73,共9页
The thermal stability of oil gels formed by styrene-butadiene-styrene triblock copolymer (SBS) was improved by adding a small amount of poly(phenylene ether) (PPE), which has a higher glass transition temperature (Tg)... The thermal stability of oil gels formed by styrene-butadiene-styrene triblock copolymer (SBS) was improved by adding a small amount of poly(phenylene ether) (PPE), which has a higher glass transition temperature (Tg). In naphthenic oil which is a good solvent for the butadiene blocks, but a non-solvent for the styrene blocks and PPE, PPE was selectively included into styrene blocks in SBS, and induced the increase of the Tg of these blocks. The melting temperature determined by viscoelastic measurements and softening temperature of the gels were elevated by adding PPE, while no significant change was detected by adding polystyrene. The gel became opaque by adding PPE, and partially separated phases were observed by field emission scanning electron microscopy (FE-SEM). The dependence of the viscoelastic behavior on the PPE concentration can be explained by the structural change observed by FE-SEM. 展开更多
关键词 styrene-butadiene-styrene TRIBLOCK Copolymer Poly(phenylene ether) (PPE) OIL Gel Naphthenic OIL
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Styrene epoxidation catalyzed by polyoxometalate/quaternary ammonium phase transfer catalysts: The effect of cation size and catalyst deactivation mechanism
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作者 Qiongna Xiao Yuyan Jiang +3 位作者 Weiqiang Yuan Jingjing Chen Haohong Li Huidong Zheng 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第3期192-201,共10页
Catalytic epoxidation of alkenes is an important type of organic reaction in chemical industry,and the deep insight into catalyst deactivation will help to develop new epoxidation process.In this work,series of quater... Catalytic epoxidation of alkenes is an important type of organic reaction in chemical industry,and the deep insight into catalyst deactivation will help to develop new epoxidation process.In this work,series of quaternary ammoniums bearing different cationic sizes,i.e.MTOA+(methyltrioctylammonium,[(C_(8)H_(17))_(3)CH_(3)N]+),HTMA+(hexadecyltrimethylammonium,[(C_(16)H_(33))(CH_(3))_(3)N]+) and DMDOA+(dimethyldioctadecylammonium,[(C_(18)H_(37))_(2)(CH_(3))_(2)N]+) were incorporated with polyoxometalate (POM) anions to prepare phase transfer catalysts (PTCs),which were used in the styrene epoxidations.Among them,(MTOA)_(3)PW_(4)O_(24)exhibits the best catalytic performance judged from the highest styrene conversion rate(52%) and styrene oxide selectivity (93%),during which the styrene epoxidation conditions were optimized.Meanwhile,the deactivation mechanism of this kind of PTCs was proposed firstly,i.e.in the case of low H_(2)O_(2) content,the oxidant can only be used in the styrene epoxidation,in which the catalyst can transform into stable Keggin-type POM.But when the content of H_(2)O_(2) is higher,the excess H_(2)O_(2) can reactivate the Keggin-type POM into active (PW_(4)O_(24))_(3)-anions,which can trigger the ring-opening polymerization of styrene oxide.Consequently,the catalyst is deactivated by adhered poly(styrene oxide)irreversibly,which was determined by NMR spectra.In this situation,the active moiety{PO_(4)[WO(O_(2))_(2)]_(4)}_(3)-in phase-transfer catalytic system can break into some unidentified species with low W/P ratio with the presence of epoxides.This work will be beneficial for the design of new PTCs in alkene epoxidation in fine chemical industry. 展开更多
关键词 Phosphotungstic acid phase-transfer CATALYST styrene epoxidation Catalyst deactivation mechanism Cation size effect
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One-pot synthesis of ordered mesoporous Cu-KIT-6 and its improved catalytic behavior for the epoxidation of styrene:Effects of the pH value of the initial gel 被引量:3
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作者 李白滔 罗歆 +2 位作者 黄静 王秀军 梁振兴 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2017年第3期518-528,共11页
The heterogeneously copper-catalyzed oxidative cleavage of styrene was studied using copper-doped mesoporous KIT-6(CU-KIT-6_x) prepared via pH adjustment(where x is the pH:1.43,2.27,3.78,3.97,4.24 or 6.62).Variat... The heterogeneously copper-catalyzed oxidative cleavage of styrene was studied using copper-doped mesoporous KIT-6(CU-KIT-6_x) prepared via pH adjustment(where x is the pH:1.43,2.27,3.78,3.97,4.24 or 6.62).Variations in the catalyst structure and morphology with pH values were characterized by X-ray power diffraction,nitrogen adsorption-desorption analysis,transmission electron microscopy and X-ray photoelectron spectroscopy.As the pH value applied during the initial synthesis,the resulting Cu-KIT-6_x exhibited different structural,textural and surface characteristics,especially in terms of specific copper species and copper content At a pH value of 3.78,approximately 4.6 wt%copper(Ⅱ) was successfully incorporated into the framework of the initial KIT-6,in the form of-Cu-O-Si- groups.The catalytic performance of each catalyst was evaluated by following the epoxidation of styrene,employing tert-butyl hydroperoxide as the oxidant and CH_3CN as the solvent.A significant styrene conversion of 43.5%with 86.6%selectivity for the desired styrene epoxide was obtained over the Cu-KIT-63.78.A higher Cu content,an ordered cubic laid mesoporous architecture and various specific textural characteristics all combined to endow the Cu-KIT-63.78 with high catalytic activity and good stability. 展开更多
关键词 Mesoporous material KIT-6 styrene epoxidation pH-adjusting
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