RSC Advances
·
2016
·Vol. 6
·期 70
·65889-65897
·
IF 3.289
Fei Liu,Jia Qiu,Jinggang Wang,Junwu Zhang,Haining Na,Jin Zhu
A unique non-planar ring structure 1,4-cyclohexanedicarboxylic acid (CHDA) is introduced to synthesize a poly(butylene adipate-co-butylene 1,4-cyclohexanedicarboxylate) (PBAC) copolyester. The impact of the stereochemistry of CHDA on the structure and properties of PBAC, especially the role of cis-CHDA in tuning the thermal, tensile and elastic properties of PBAC is explored in depth. Instead of considering PBAC as a diblock random copolymer consisting of poly(butylene adipate) (PBA) and poly(butylene 1,4-cyclohexanedicarboxylate) (PBC), our results reveal that PBAC can be considered as a random copolymer consisting of actually three blocks, namely PBA, a PBC unit with only trans-CHDA (trans-PBC), and PBC unit with only cis-CHDA (cis-PBC). The role of cis-CHDA is found to be rigid which initiates a high modulus and strength, and soft which results in a decreased melting temperature and increased elongation at break and elasticity.
研究领域:
材料科学
·
聚合物化学
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DOI
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 39
·21926-21932
·
IF 2.936
Jie Liu,Xiaodong Fan,Xin Min,Xiuzhong Zhu,Na Zhao,Zichao Wang
This work explores the synthesis of polybutadiene (PB) with high cis-1,4 unit content and narrow molecular weight distribution using a neodymium-based complex, consisting of neodymium(III) trifluoromethane sulfonate (Nd(CF3SO3)3) and coordinated with tris(2-ethylhexyl)phosphate (TOP). The complex's composition and structure are characterized by elemental analysis, XPS and FT-IR. Combined with Al(i-Bu)3, a binary catalyst is obtained and then applied to initiate the polymerization of butadiene. Results indicate that the catalyst system displays a high catalyst activity and the product polymer (PB) features a high cis-1,4 content (98.8%) and a remarkably narrow molecular weight distribution (Mw/Mn = 1.32). Compared with PB initiated by the current well-studied catalyst Nd(CF3SO3)3*3TBP/Al(i-Bu)3, the Nd(CF3SO3)3*3TOP allows significantly narrowing the molecular weight distribution of the PB, because the Nd(CF3SO3)3*3TOP is more easily dissolved in hexane. Therefore, butadiene was polymerized in a homogenous system and each monomer's polymerization was initiated in the single molecular state.
研究领域:
材料科学
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催化化学
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产品关联
DOI
PubMed
高影响因子
MACROMOLECULAR RAPID COMMUNICATIONS
·
2024
·Vol. 45
·期 22
·2400486
·
IF 4.2
Liying Shen,Jingjing Zhai,Yanchen Huo,Xiuling Wang,Xiaochao Shi
A series of binuclear rare-earth metal complexes based on the ligands containing bis(phosphinophenyl)amido-PNP unit are successfully synthesized. All the ligands and the corresponding binuclear complexes are fully characterized by NMR spectra ( 1 H, 13 C, and 31 P). In conjunction with [Ph 3 C][B(C 6 F 5 ) 4 ], all the binuclear complexes exhibited high catalytic activity and high cis -1,4-selectivity (>99%) toward the polymerization of 1,3-conjugated dienes (isoprene, β-myrcene and β-farnesene) with excellent livingness at room temperature or even 80 °C.
研究领域:
有机化学
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高分子化学
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催化化学
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产品关联
DOI
PubMed
高影响因子
Polymers
·
2021
·Vol. 13
·期 19
·3329
·
IF 4.329
Beibei Wang,Heng Liu,Tao Tang,Xuequan Zhang
Highlycis-1,4 selective (up to 98%) coordination–insertion polymerization of 1,3-butadiene (BD) has been achieved herein using acenaphthene-basedα-diimine cobalt complexes. Due to the presence of intra-ligand π-π stacking interactions, the complexes revealed high thermostability, affording polybutadiene products in high yields. Moreover, all of the obtained polymers possessed a relatively narrow molecular weight distribution as well as high molecular weight (up to 92.2 × 104Dalton). The molecular weights of the resultant polybutadienes could be finely tuned by varying polymerization parameters, including temperature, Al/Co ratio, etc. Moreover, the copolymerization of butadiene with polar monomer 2-(4-methoxyphenyl)-1,3-butadiene (2-MOPB) was also successfully realized to produce a type of polarcis-1,4 polybutadiene (cis-1,4 content: up to 98.1%) with a range of 2-MOPB content (0.46–1.83%). Water contact angle measurements indicated that the insertion of a polar monomer into a polymer chain could significantly improve the polymer’s surface property.Keywords:cis-1,4 selective;1,3-butadiene;α-diimine cobalt complexes;copolymerization;π-π stacking interactions
研究领域:
高分子化学
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配位化学
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DOI
PubMed
高影响因子
Polymers
·
2019
·Vol. 11
·期 4
·598
·
IF 3.164
Xin Min,Xiaodong Fan
This work reports the preparation of a hydroxyl terminated polystyrene-b-polybutadiene-b-polystyrene triblock copolymer (SBS) with high cis-1, 4 content via a novel nickel catalyst, [η3-Ni(CH2CHCHCH2OOCH3)][BPhF4]. FT-IR,1H-NMR, and13C NMR indicated that the polybutadiene segment of the copolymer contains greater than 90% cis-1, 4 structure, indicating achievement of the objective. Toward the functionalization goal, a hydroxyl group was successfully introduced at the end of the triblock copolymer (HO–SBS–OH). The results of gel permeation chromatography (GPC) revealed that the polymer is indeed a triblock copolymer, with no traces of homopolymer. Differential scanning calorimetry (DSC) showed that HO–SBS–OH synthesized using the novel catalyst had a lower glass transition temperature (Tg) than HO–SBS–OH synthesized with an alkyl lithium catalyst. Therefore, the polymer synthesized via the novel catalyst contains high cis-1,4 content and displays excellent low-temperature mechanical properties.Keywords:hydroxyl terminated polystyrene-b-polybutadiene-b-polystyrene triblock copolymer;high cis-1,4 content;nickel catalyst
研究领域:
材料科学
·
高分子化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2016
·Vol. 134
·期 1
·
IF 1.866
Zhaowei Wang,Zhixia Wen,Xing Li,Junwei Yu,Xiaoxuan Liu
The preparation of the high cis −1,4-polyisoprene by Ziegler-Natta catalysis system was studied. The effect of Al-Ti catalysts modified by ethers with different structures which are different electron donor reagent on polymerization of isoprene has been mainly investigated. By the measurement method of the monomer conversion, FTIR, and 1 H NMR spectroscopy, the influence of, respectively, added diphenyl ether, anisole, dibutyl ether, or methyl tert -butyl methyl ether as a third active component on the heterogeneous TiCl 4 -Al( i -Bu) 3 -ether catalyst activity and microstructure of synthetic polyisoprene was analyzed. By the adding of diphenyl ether or dibutyl ether, the process of prefabricated heterogeneous catalyst is quickly and catalyst particle quantity is large. The polymerization conversion is high and the microstructure cis −1,4 content of the resulting polymer can reach 92%. But Al( i -Bu) 3 added anisole or methyl tert -butyl methyl ether hard to cooperate with TiCl 4 . © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 44357.
研究领域:
高分子化学
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催化化学
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功能材料
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合成高分子
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配位聚合
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DOI
高影响因子
ACS Omega
·
2020
·
IF 2.87
Meiying Huang,Lijun Gao,Jiuying Feng,Xuyi Huang,Zengquan Li,Zetian Huang,Lingyun Wang
Poly(propylene carbonate) (PPC) from CO2 and propylene oxide (PO) has wide potential applications as a degradable “plastic”. However, the thermal stability and mechanical properties of PPC cannot meet most of the application requirements. Herein, we focus on improving these properties. A (maleic anhydride/cis-1,2,3,6-tetrahydrophthalic anhydride) (MA/THPA) oligomer containing several cyclocarboxylic anhydride groups, which can copolymerize with PO, has been readily synthesized and used as the third comonomer to prepare PPC with cross-linked networks. The gel contents increase from 16 to 42% with increasing MA/THPA oligomer feed contents from 0.5 to 4 wt % of PO. The formation of cross-linked networks in PPC greatly improves the thermal, mechanical, and dimensional properties. The 5% weight-loss degradation temperature increases from 217 °C to nearly 290 °C before and after cross-linking, which ensures that PPC does not decompose in melt processing. The tensile strength of the copolymer is in the range of 22.2–44.3 MPa with elongation at break of 11–312%. The maximum tensile strength is improved by 143% compared to that of PPC. When the MA/THPA oligomer feed is above 3 wt % of PO, the hot-set elongation of the copolymer at 65 °C decreases more than 10 times when compared with that of PPC, and the permanent deformation is close to 0, while it is 145% for PPC. The dimensional stability is improved sharply. It can overcome the cold flow phenomenon of PPC. The improvement of the above comprehensive properties is of great significance to the practical application of PPC in various fields.
研究领域:
材料科学
·
高分子化学
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DOI
PubMed
高影响因子
Molecular Catalysis
·
2024
·
IF 3.9
Qingtao Niu,Aihua He,Chongdian Si,Guodong Liu,Bolin Dai,Manman Jin
Two TiCl 4 /MgCl 2 type Ziegler-Natta catalysts containing ethyl benzoate (EB) and dibutyl phthalate (DBP) as internal electron donors (ID) were prepared for isoprene polymerizations using five kinds of external electron donors (ED) (phenyltrimethoxysilane (ED-1), dicyclopentyl(dimethoxy)silane (ED-2), 2-butyl-2-ethyl-1,3-dimethoxypropane (ED-3), 1,3-dimethoxypropane (ED-4) and di(2-ethylhexyl)phthalate (ED-5)). The structure features of TiCl 4 /ID/MgCl 2 catalysts were characterized and the effect of ID and ED on polymerization behaviors was studied. EB had higher adsorption content on catalyst surface, higher catalytic activity and lower trans -1,4 stereoselectivity than DBP . Appropriate introduction of ED-1 and ED-2, expect ED-3, ED-4 and ED-5, caused the enhancement in polymerization activity and trans -1,4 content, while excess addition led to the deactivation. The effect of ED on equilibrium between selective activation and deactivation of active species significantly relied on the electron donor type and concentration.
研究领域:
高分子化学
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催化
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材料科学
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产品关联
DOI
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Jiangwen Guo,Songbo Zhang,Juntao Ren,He Li,Shuwei Wang,Yanming Hu,Guangyuan Zhou
A series of pyridylbenzotriazole iron (II) complexes with general formula (L 2 FeCl 2 ) were synthesized and characterized by IR, ESI-MS, and elemental analysis . Determined by single-crystal X-ray crystallography, complex Fe1 adopts a distorted octahedral geometry. Upon activation with methylaluminoxane (MAO), the activity of the complex for isoprene polymerization decreased as the bulkiness of the substituent at 6-position of the pyridyl ring of the ligand increased. Notably, Fe1 exhibited excellent activity of 4.1 × 10 6 g/(mol (Fe)•h), affording polymers with ultra-high molecular weight ( M n = 2380 × 10 3 g/mol) and narrow distributions ( M w / M n = 1.72). The resulting polyisoprenes possessed predominantly cis -1,4/3,4 alternating structure and short cis -1,4 and 3,4 sequences, irrespective of the reaction conditions, indicating high thermal stability of the catalyst. Moreover, the prepared polyisoprene composite showed higher mechanical properties compared to SSBR-2466 and SSBR-5025 which are the key components of current commercial tread rubber, and had comparable wet traction and superior rolling resistance.
研究领域:
催化
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高分子科学
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材料科学
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DOI
高影响因子
BIOTECHNOLOGY LETTERS
·
2020
·Vol. 42
·期 8
·1501-1511
·
IF 1.977
Chang Ya-Wen,Zhang Jian-Dong,Yang Xiao-Xiao,Li Jing,Gao Li-Li,Huang Shuang-Ping,Guo Xing-Mei,Zhang Cao-Feng,Chang Hong-Hong,Xu Jian-He
Objectives To screening of bacteria with cyclic amino alcohol deamination activity for enantioselective synthesis of chiral cyclic β-amino alcohols. Results A new strain named Arthrobacter sp. TYUT010-15 with the ( R )-selective deamination activity of cyclic β-amino alcohol has been isolated from nature via a high throughput solid-phase screening method. The reaction conditions of TYUT010-15 were optimized. Using the resting cell of TYUT010-15 as the catalyst, kinetic resolution of trans -2-aminocyclopentanol, trans -2-aminocyclohexanol and cis -1-amino-2-indanol was carried out to afford (1 S , 2 S )- trans -2-aminocyclopentanol, (1 S , 2 S )- trans -2-aminocyclohexanol and (1 R , 2 S )- cis -1-amino-2-indanol in > 99% ee and 49.6–50% conversion. Four aromatic β-amino alcohols and two amines were also resolved, ( S )-β-amino alcohols and ( R )-amines were obtained in > 99% ee. Preparation experiment was conducted with 200 mM (23.2 g L −1 ) racemic trans -2-aminocyclohexanol, yielding the desired (1 S , 2 S )- trans -2-aminocyclohexanol in 40% isolated yield, > 99% ee and 5.8 g L −1 d −1 space time yields. Conclusions This study provides a high throughput solid-phase method for screening of bacteria with cyclic amino alcohol deamination activity and a first example for practical preparation of chiral cyclic β-amino alcohol by Arthrobacter sp. TYUT010-15.
研究领域:
微生物学
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有机化学
·
生物催化
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手性化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2024
·Vol. 31
·期 2
·1-16
·
IF 2.6
Guo Liyun,Zhang Haichang,Hua Jing,Liu Jinhui
Cis-1,4 - polyisoprene latex (IRL) is the best alternative to natural rubber latex (NRL) because it is free from proteins and can avoid allergic reactions in the human body. Poor mechanical properties of IRL film are a major obstacle to replacing NRL. To address this issue, a novel strategy was developed by a simple one-pot method to prepare a composite latex introducing hexadecyltrimethylammonium bromide (CTAB) modified sodium montmorillonite (org-Mnt) into the IRL preparation process. The microstructures and morphology of the resulting org-Mnt were characterized by Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), and Energy Dispersive Spectrometer (EDS). In addition, the dispersion state of the org-Mnt in the composite latex and the morphology of the composite films were determined by transmission electron microscopy (TEM) and SEM. The properties of the composite latex were investigated. Crosslink density, thermogravimetric analysis (TGA), mechanical properties, and thermal oxygen aging properties of the composite latex films were also studied. Finally, the mechanism of org-Mnt reinforcement of IRL was described comprehensively. The results showed that the org-Mnt/IRL (1phr and 2phr) composite latexes had a stable state, excellent film-formation performance, and excellent mechanical properties. Compared with pure IRL films, the tensile strength of org-Mnt/IRL (2phr) composite films increased by 74%, and after thermal oxygen aging, property change rates of the tensile strength and elongation at break increased by 37.2% and 32.1%, respectively, which exceeded those of NRL. The current research provides an effective method for preparing high-performance composite films suitable for high-end medical applications.
研究领域:
高分子科学
·
材料工程
·
纳米复合材料
·
胶体与界面科学
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生物医用材料
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DOI
高影响因子
危险品化学品经营许可证（带存储）