Catalysis Science & Technology
·
2013
·Vol. 4
·期 3
·773-779
·
IF 3.753
Qinzhuo Zhou,Bo-Geng Li,Suyun Jie,Na Zheng
A series of phosphine-containing cobalt complexes [CoCl2(PRPh2)2, R = Ph (1), Cy (2), nPr (3), Et (4), Me (5), H (6)] has been used for the highly active and stereospecific polymerization of 1,3-butadiene upon activation with ethylaluminum sesquichloride (EASC). The high catalytic activities and polybutadienes with high cis-1,4 selectivity were obtained in the solution polymerization in toluene. The conversion of butadiene and the microstructure and molecular weight of the resulting polymers were affected by reaction parameters and the R group on the phosphine ligand. The dispersion medium was also a sensitive factor for the current catalytic systems, influencing the catalytic activity and properties of products. In comparison with the solution polymerization in toluene, the heterogeneous polymerization in isooctane yielded slightly lower catalytic activity, cis-1,4 content and molecular weight under similar reaction conditions.
研究领域:
高分子化学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2016
·
IF 3.586
Jie Liu,Zhenghai Tang,Jing Huang,Baochun Guo,Guangsu Huang
In order to simulate the effect of non-rubber components on strain-induced crystallization (SIC) in natural rubber (NR), sacrificial metal-ligand bonds are incorporated, for the first time, into cis -1,4 polyisoprene cured by sulfur. The incorporation of sacrificial bonds is found to bring in much smaller onset strain for SIC and higher crystallinity compared with the cis -1,4 polyisoprene with sulfide crosslinks only. Accordingly, the striking improvements in tensile modulus and fracture toughness are achieved. The present work contributes to significant insights for mimicking NR outstanding properties in synthesized cis -1,4 polyisoprene and affords new technological route in improving the mechanical properties of synthesized polyisoprene alternative to the nanofilling.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER COMPOSITES
·
2025
·
IF 4.7
Liyun Guo,Haichang Zhang,Jing Hua
To better substitute natural rubber latex (NRL) with cis -1,4-polyisoprene latex (IRL), and thus fundamentally solve the problem of allergies induced by NRL products in humans, a novel latex compounding method was devised. This method aimed to enhance the mechanical properties of IRL films by non-covalently modifying graphene oxide (GO) with ionic liquids (IL), which significantly improved the dispersion of GO in water. The interaction between IL and GO was thoroughly investigated. Subsequently, IL-GO/IRL composite latexes featuring a fine dispersion of IL-GO were successfully developed. An extensive investigation into the properties and morphology of the IL-GO/IRL latex revealed their stability, excellent film-forming abilities, and superior mechanical characteristics, rendering them ideal for dipping processes. The resulting thickness-adjustable IL-GO/IRL composite films exhibited remarkable mechanical properties. Notably, the tensile strength of the 1.5IL-GO/IRL vulcanized film surpassed that of GO/IRL films by 2.75 times and NRL films by 10.49%. Additionally, the crosslinking density of the IL-GO/IRL vulcanized films was improved. Further analysis of the interaction between IL-GO and polyisoprene macromolecules was also conducted. The composite films are poised to find applications in high-end medical and artificial intelligence fields. Highlights Mechanical performance of IRL was enhanced by introducing IL-GO. Fine GO dispersed composite latexes were ideal for the dipping process. Composite films boast superior mechanical properties surpassing NRL films. Resulting composite film was thickness-adjustable and ultra-thin. CC bonds in IL and IR formed covalent linkages, boosting GO-IR chain interaction.
研究领域:
材料科学
·
医学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ORGANOMETALLIC CHEMISTRY
·
2015
·
IF 2.173
Shuai Lv,Suyun Jie,Bo-Geng Li
A series of bis{[2-(4,5-diphenylimidazolyl)phenylimino]phenolate}cobalt(II) complexes ( C1 – C4 ) has been synthesized and characterized. Single-crystal X-ray analysis demonstrated that the cobalt center was coordinated by two [NNO – ] ligands and adopted a slightly distorted octahedronal geometry. The type of cocatalyst had a remarkable influence on the catalytic properties and ethylaluminum sesquichloride (EASC) was proved to be more efficient for the polymerization of 1,3-butadiene to produce higher conversion of butadiene and cis -1,4 content of polybutadienes . On activation with EASC, all the cobalt complexes displayed high catalytic activity for the polymerization of 1,3-butadiene. The microstructure determined by FT-IR and NMR spectra demonstrated that high cis -1,4 contents in the resulting polymers were obtained. The conversion of butadiene , microstructure, molecular weight and molecular weight distribution of polybutadienes were influenced by the reaction parameters and ligand structure .
研究领域:
高分子化学
·
配位化学
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2024
·
IF 4.3
Xuyang Yan,Wentao Chen,Wang Xie,Xiuling Wang,Yat-Ming So,Xiaochao Shi
We have synthesized a series of binuclear rare-earth metal complexes bearing the newly designed enamino-oxazolinate ligands that feature bridging para-phenyl, meta-phenyl, 1,5-naphthalenyl, and 1,5-anthracenyl moieties. NMR and X-ray diffraction analyses confirmed the binuclear structures of the obtained complexes with two enamino-oxazolinate-metal units located at a trans position against the bridged aryl plane. After activation by [Ph3C][B(C6F5)4], all the rare-earth metal complexes served as efficient catalysts for isoprene polymerization, producing polymers with high cis-1,4 regularity (up to 96.1%) and high molecular weight. The steric and electronic effects exerted on the active metal centers, as well as the radius of metal centers, were the major contributing factors for determining both the catalytic activity and cis-1,4-selectivity of the binuclear catalytic systems. Compared to its mononuclear analogue, the binuclear yttrium catalytic system with a para-phenyl bridge exhibited a higher thermostability and catalytic efficiency during polymerization, revealing a special binuclear effect in this binuclear catalytic system.
研究领域:
化学
·
材料科学
·
催化反应
✓ 已验证
DOI
PubMed
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 67
·39037-39045
·
IF 3.049
Xin Min
In this study, novel hydroxyl-terminated polybutadiene (HTPB) with a high cis-1,4 content was developed using a tert-butyl dimethyl siloxy dimethyl propyl lithium (Li)–naphthenate nickel (Ni)–boron trifluoride (B) initiating system (Li–Ni–B). The effects of the material ratio and the addition sequence on the cis-1,4 content and molecular weight of HTPB were studied, and the results were discussed. The optimal Li/Ni ratio was 10 : 1, and the optimal Li/B ratio was 1 : 2. HTPB prepared by the Li–Ni–B system was characterized by Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance (1H-NMR) spectroscopy, and 13C nuclear magnetic resonance (13C-NMR) spectroscopy. The results suggested high cis-1,4 contents in HTPB synthesized using Li–Ni–B (cis-1,4 > 95%). The comparison of the cis-1,4 contents in the HTPB samples obtained by anionic polymerization and the Li–Ni–B system revealed the advantages of the latter compared to the former.
研究领域:
材料科学
·
聚合物化学
✓ 已验证
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2014
·
IF 2.235
Qinzhuo Zhou,Suyun Jie,Bo-Geng Li
Hydroxyl-terminated polybutadiene (HTPB) with high cis-1,4 content (>95.0%) has been prepared via a two-step method by taking commercial butadiene rubber (BR9000) as a starting material, including the one-pot synthesis of aldehyde-group-terminated polybutadiene (ATPB) in high efficiency and the subsequent reduction reaction. The double bonds distributed in linear polybutadiene were first epoxidized and then cleaved at the exact epoxidized sites. The epoxidation reaction by 3-chloroperbenzoic acid and chain-cleavage reaction by periodic acid are controllable, highly efficient, selective, and quantitative. Along with an epoxy percent increase, the molecular weight of ATPB prepared via a one-pot method decreased with a relatively narrow polydispersity index. The aldehyde groups in the chain ends were reduced by NaBH4 to produce HTPB, in which the high cis-1,4 content of BR was retained.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2024
·Vol. 53
·期 25
·10563-10570
·
IF 3.5
Shuhao You,Wenyu Shi,Ruoxue Ouyang,Yang Wang,Xiaochao Shi
A series of bis(oxazoline) rare-earth metal dialkyl complexes [(L)Ln(CH2SiMe3)2(THF)n] (L = L1 (dimethyl-substituted bis(oxazoline) ligand), Ln = Y (1-Y), Lu (1-Lu), Sc (1-Sc), n = 1; L = L2 (phenyl-substituted bis(oxazoline) ligand), Ln = Y (2-Y), Lu (2-Lu), Sc (2-Sc), n = 2) was successfully prepared. NMR spectroscopy and X-ray diffraction indicated that all the complexes ligated with a C2 symmetric bis(oxazoline) and two trimethylsilylmethyl ligands. In the presence of borate and triisobutyl aluminium, these complexes exhibited high catalytic activity for the polymerization of isoprene, yielding the polymer with high cis-1,4-regularity (up to 99.9%) and high molecular weight. Moreover, these ternary catalytic systems also served as efficient initiators for the polymerization of polar ortho-methoxystyrene. However, atactic polymers in all the cases were isolated despite the C2 symmetric geometry of bis(oxazoline) ligands.
研究领域:
化学
·
高分子科学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2025
·
IF 2.1
Yufan Yang,Muran He,Yichan Zhang,Chunting Zhou,Chunhuan Luo
The cis-1-chloro-3,3,3-trifluoropropene (R1233zd(Z)) and tetraethylene glycol dimethyl ether (TEGDME) system has been proposed in this study as a potential alternative absorption working pair. The vapor pressure, density, viscosity, and specific heat capacity of the R1233zd(Z)/TEGDME system were measured systematically. The mixing enthalpy and specific enthalpy were calculated by the NRTL model. Regression equations for the measured values were obtained by a least-squares method. Compared with the LiBr/H2O system, the generation temperature of the R1233zd(Z)/TEGDME system is reduced by 12 °C and the viscosity by about 50%. R1233zd(Z)/TEGDME has strong practical application significance in the absorption heat pump system.
研究领域:
化学工程
·
热力学
·
制冷技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）