CHINESE JOURNAL OF POLYMER SCIENCE
·
2018
·Vol. 36
·期 10
·1150-1156
·
IF 2.016
Qiu Wei-Guang,Zhang Fei-Long,Jiang Xu-Bao,Kong Xiang-Zheng
Polyureas (PU) are well known as a class of high impact engineering materials, and widely used also in emerging advanced applications. As a general observation, most of them are only soluble in a very limited number of highly protonic solvents, which makes their chemical structure analysis a great challenge. Besides the presence of abundant hydrogen bonding, the poor solubility of PU in common organic solvents is often ascribed to the formation of biuret crosslinking in their molecular chains. To clarify the presence of biuret groups in PU has been of great interest. To this end, two samples, based on hexamethylene diisocyanate (HDI) and toluene diisocyanate (TDI) respectively, were synthesized by precipitation polymerization of each of these diisocyanates in water-acetone at 30 °C. Their chemical structures were analyzed by high resolution magic angle spinning (HR-MAS) NMR, and through comparison of their NMR spectra with those of specially prepared biuret-containing polyurea oligomers, it was concluded that biuret group was absent in all the PU prepared at 30 °C. In addition, this NMR analysis was also applied to a PU obtained by copolymerization of TDI with ethylene diamine (EDA) and water at 65 °C in EDA aqueous solution. It was confirmed that biuret unit was also absent in this PU and that EDA was more active than water towards TDI. The presence of EDA was crucial to the formation of uniform PU microspheres. This study provides therefore a reliable method for the analysis of PU chemical structure.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2014
·Vol. 32
·期 7
·931-940
·
IF 1.42
Liu Rui-yuan,Zhang Tong,Yang Xiao-dong,Yan Yi-chen,Qu Jin-qing
A novel phenylacetylene derivative containing urea groups was synthesized and polymerized with a Rh catalyst to give the corresponding polymer, poly( 1 ) with moderate number-average molecular weights. The poly( 1 ) was soluble in toluene, CHCl 3 , CH 2 Cl 2 , THF, DMF, and DMSO, but insoluble in hexane, diethyl ether and MeOH. The specific rotation and circular dichroism (CD) spectroscopic studies revealed that poly( 1 ) took predominantly one-handed helical structures. The presence of intramolecular hydrogen bonding was confirmed by liquid-state IR spectroscopy. The helicity of poly( 1 ) could be tuned by temperature and anion. The helical conformation of the polymer was stable against Br- but susceptible to F − .
研究领域:
有机化学
·
高分子化学
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产品关联
DOI
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2016
·Vol. 217
·期 16
·1851-1859
·
IF 2.495
Rui Qi,Yong Jin,Xinfeng Cheng,Hanping Li,Shuangquan Lai,Xiaopeng Sun
Herein, a novel coil-rod-coil triblock copolymer with the coil blocks composed of poly(ethylene glycol) methyl ether and the rigid midterm block alternatively connected with isophorone diisocyanate and isophorone diamine is developed. The triblock copolymer can self-assemble into ellipsoidal micelles in 1-methyl-2-pyrrolidinone. After the addition of a second coil-selective solvent (water) to the micellar solutions, these ellipsoidal micelles can further transform into chain-like nanostructures. The self-assembly behavior is highly influenced by the additional order of the solvents, which is considerably due to the impacts of the hydrogen-bonding urea groups and rigid motifs. The transition of the ellipsoidal micelles to chain-like nanostructures is governed by the water molar fractions. The sizes of the chain-like nanostructures increase first and then decrease with the growth of the water molar fractions in the mixed solutions.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
LIQUID CRYSTALS
·
2014
·
IF 2.349
Fafu Yang,Jin Yuan,Congcong Li,Hongyu Guo,Xiaoyun Yan
Series of triphenylene derivatives with multiple NH groups 3a, 3b, 4a, 4b, 5a and 5b were designed and synthesised by simple procedures in high yields. Their structures were confirmed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), mass spectrometry (MS) and elemental analysis. Their mesophase behaviours were studied by differential scanning calorimetry, polarising optical microscopy and X-ray diffraction. The triphenylene derivatives 3a and 3b with two NH groups and triphenylene derivatives 4a and 4b with three NH groups possess excellent mesomorphic properties. Compounds 4a and 4b exhibited wider mesophase than compounds 3a and 3b. Triphenylene derivatives 5a and 5b with five NH groups have no mesomorphic properties. These results suggested the units of hydrogen bonds played the crucial roles on mesomorphic properties and acylthiosemicarbazide group with three NH groups was a good functional group for producing excellent mesomorphic properties.
研究领域:
材料化学
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物理化学
✓ 已验证
DOI
高影响因子
DESALINATION
·
2025
·
IF 9.8
Liting Luo,Hao Li,Jiazheng Zhou,Wenjie Li,Abdul Haleem,Jianming Pan
Developing magnetic adsorbents with superior adsorption capability has always been a massive challenge. Herein, an in-situ growth strategy was implemented to build polydopamine-encapsulated lightweight hollow magnetic microspheres and used to achieve selective recovery of gold from e-waste. The fabricated magnetic-dielectric microspheres, including hollow magnetic polydopamine microspheres (HMPM) and hollow magnetic polydopamine microspheres modified by allyl thiourea (HMPM&A), exhibited excellent gold adsorption capacities of 1205 mg g −1 and 1766 mg g −1 , respectively at 298 K. The adsorption capacity was amazingly upsurged up to 1850 mg g −1 and 2715 mg g −1 under ultraviolet light, respectively, which is relatively enhanced compared to other reported magnetic adsorbents. The XPS survey and DFT calculations confirmed that Au(III) ions adsorption principally attributed to electrostatic interaction of N sites under acidic mediums and chelating interaction between Au(III) and S,N chelating site of thiourea groups, followed by subsequent reduction of Au(III) into to Au(0) with thiourea and dopamine units. The developed magnetic adsorbent showed impressive chemical stability for Au(III) adsorption up to eight consecutive adsorption-desorption cycles without any noticeable change in adsorption performance. The recovery rate of HMPM&A for Au(III) ions from actual samples was better up to 86.7 %. This work will broaden the construction strategy of magnetic adsorbents and promote the application of magnetic materials as an efficient functional material.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
DYES AND PIGMENTS
·
2016
·
IF 4.055
Miaomiao Hong,Shengzhou Lu,Feng Lv,Dongmei Xu
A novel rhodamine-based turn-on fluorescent probe with three thiourea receptors was designed, synthesized and fully characterized. In acetonitrile/4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid buffer (9/1, v/v, pH = 7.21), the probe showed high selectivity and sensitivity to Hg 2+ with a 20-fold fluorescence enhancement at 583 nm. The increase in fluorescence intensity was linearly proportional to the concentration of Hg 2+ in the range of 25–200 μM with a detection limit of 3.04 × 10 −7 M. The probe could work in a nearly neutral pH span of 6.41–8.33 and exhibited excellent interference immunity. Real sample assay showed the probe had good practicability. The results from Job's plot, reversibility experiment, mass and infrared spectra analysis suggested a 1:3 probe/Hg 2+ complex with an association constant of 9.88 × 10 11 M −3 and a new interaction way between the probe and Hg 2+ .
研究领域:
分析化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2023
·
IF 3.8
Wulan Zeng,Xia Wang,Xiangjun Kong,Youwang Li,Yunju Zhang
A new spirocompound containing thiourea group 1-((2,4-dioxo-1,5-dioxaspiro[5.5]undecan-3-ylidene)methyl)-3-phenylthiourea (DMP) was designed and obtained. The compound (DMP) was confirmed using the single X-ray diffraction, 1 H NMR and 13 C NMR, IR, Raman, MS and UV–Vis. The DFT calculations of molecular structure, infrared and Raman spectroscopy and electronic transition were performed using the two different levels of B3LYP/cc-pVDZ/ and B3LYP/6–311G(d, p). The theoretical results match with the experimental ones. The gap energy of HOMO and LUMO of DMP was 3.88 eV. The DMP is thermally stable up to 200 °C according to the data obtained from TG analysis. Finally, the Mulliken population analysis, Hirshfeld surfaces analysis, MEP, NLO and NBO of DMP were discussed.
研究领域:
化学
·
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2025
·
IF 3.3
Zipeng Tang,Chunlong Wang,Chunying Ma,Wenzhen Zou,Chao Wei,Xuanshuo Shanguan,Lu Zhou,Xiaoyu Li,Yongchun Ye,Liguo Gao,Yusran Sulaiman,Tingli Ma,Chu Zhang
Senior oxygen-related defects including O vacancies and dangling O-H bonds in the SnO2 ETL result in non-radiative carrier recombination, which directly affect the efficiency performance and stability of perovskite solar cells. Meanwhile, undercoordinated Pb2+ can also induce non-radiative recombination of photogenerated carriers and provide a pathway for ion migration, leading to further degradation of solar cell performance. To tackle such issues, interface modification with multi-functional small molecules is usually considered a convenient way to inhibit non-radiative recombination and improving carrier transportation. Here, we employ two isothiourea group-based bridge molecule CESC (S-carboxyethyl isothiourea hydrochloride) together with DASC (S-[2-(Dimethylamino) ethyl] isothiourea Dihydrochloride) to passivate the burial interface between SnO2 and perovskite, realizing the dual functional passivation towards both filling O2- vacancy in SnO2 lattice and binding the uncoordinated ions. Perovskite solar cells fabricated with this method shows well-improved optoelectronic performance as well as resistance against ambient moisture. Compared with the control device (17.20%), the efficiency of the devices modified by DASC and CESC increased to 18.75% and 19.04%, respectively. The unpackaged solar cells treated with CESC and DASC maintained 91.2% and 89.5% of their initial efficiency, respectively, after aging for 1000 hours in a high humidity environment.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 107
·105744-105754
·
IF 3.289
Zhe Ma,Bing Liao,Kun Wang,Yongqiang Dai,Jianheng Huang,Hao Pang
Two new flexible cardanol-based epoxy curing agents with cross-linkable thiourea groups ([2-(2-amino-ethylamino)-ethyl]-thiourea of modified cardanol and [2-(2-amino-ethylamino)-ethyl]-thiourea of modified cardanol 2,3-dihydroxy propyl ether, ETC and TCP for short, respectively) were synthesized using a Mannich reaction. The structure of the prepared curing agents was analyzed by a nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR). The curing kinetics of ETC (or TCP) cured diglycidyl ether of biphenyl A (DGEBA) epoxy resins was investigated using the Kissinger, Flynn–Wall–Ozawa and Crane methods by non-isothermal differential scanning calorimetry (DSC). Thermal properties of the cured epoxy resins were evaluated with thermogravimetric analysis (TGA) and DSC. The morphology and mechanical properties of the cured epoxy resins were also studied. The results showed that the epoxy curing agents had a high-reactivity and a low-viscosity, especially at low temperatures. The activation energy of ETC/DGEBA and TCP/DGEBA calculated by the Kissinger method were 53.6 and 60.5 kJ mol−1, respectively. The toughness of the cured epoxy resin was noticeably improved by the introduction of two new flexible curing agents. The glass transition temperature (Tg) decreased with the introduction of cardanol-based curing agents in an epoxy resin system. In addition, the cured epoxy materials exhibited good mechanical properties.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2019
·
IF 3.771
Haibing Wei,Liewu Tong,Sheng Yu,Jujia Zhang,Yu Dong,Xueliang Li,Yunsheng Ding
To investigate the effects of noncovalent intermolecular interaction on the performance of anion exchange membranes (AEMs), two types of side chain urea-containing poly(phenylene oxide)-based AEMs, namely, benzyl urea-linkaged terminal quaternary ammonium (QA)-containing AEMs (bU-AEMs) and benzyl QA-linkaged urea-containing AEMs (sU-AEMs), were synthesized and comparatively studied. The analyses by solubility test and variable-temperature infrared spectroscopy showed that the urea-based hydrogen-bonding strength in bU-AEMs was higher than that of sU-AEMs. The bU-AEMs were characterized with a stable water uptake (WU), as well as high swelling resistance relative to that of the sU-AEM counterparts, as the temperature increases. A high chloride conductivity of 50.3 mS cm −1 was achieved for bU-AEM-0.45 at 90 °C, while its WU maintained a moderate value (80.6 wt%). The H 2 -O 2 single fuel cell performance using the bU-AEM-0.35 membrane as a separator reached a peak power density of 68 mW cm −2 , which was higher than that of the sU-AEM-0.35 sample with 48 mW cm −2 . More importantly, there was less than 10% conductivity loss for the bU-AEMs after incubation in 1 M NaOH at 60 °C after 7 days, while approximately 30% loss was observed for the sU-AEMs. The results indicated that the hydrogen-bonding crosslinking strategy, as well as the configuration of H-bonding groups, provides a platform to tune the properties of AEMs suitable for fuel cell applications .
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION SCIENCE AND TECHNOLOGY
·
2016
·
IF 1.083
Maosheng Deng,Ying Huang,Xin Zhang,Zhijun Feng,Jinfeng Gou,Binjie Sun
A novel chelating resin bearing amidinothiourea (ADTU) moieties was prepared by chloroethyl crosslinked polystyrene (CMPS) with ADTU in the presence of a phase transfer catalyst. Fourier transform infrared spectra (FT-IR) and scanning electron microscopy (SEM) were used to characterized the resulting chelating resin. The saturated adsorption capacity of Hg(II) ions estimated from the Langmuir model was up to 1215 mg g−1at 313 K. Furthermore, the resin was able to selectively separate Hg(II) from multicomponent solutions with Cd(II), Co(II), Cu(II), Zn(II), Mg(II) and Pb(II). The desorption process showed the mercury recovery reached to 99.2% under eluting condition of 1 M HCl + 8% thiourea.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Zhichao He,Tao You,Fan Wu,Yingchun Li,Li Liu,Fei Wang,Yudong Huang
Thanks to the high affinity, adsorbents with sulfur-containing groups are usually used to recover Au ions, but neglect of the availability and utilization of introduced groups often makes the effort wasted, limiting the practical application of adsorbents severely. Here, we designed and fabricated two ANF-based aerogels with free and anchored thiourea groups respectively, and the adsorption performance and key influence factors were investigated by combining experiments and MD simulations. The experimental results showed that two aerogels exhibited distinct performance of adsorbing Au ions. And MD simulations results disclosed the structure difference of thiourea groups on the surface of two aerogels. The one with better performance had freer sulfur-containing groups, and these groups were easy to change their conformation, resulting in easier interaction with Au ions. However, groups on the surface of the other one were anchored. This difference in structure and resultant performance indicated that the freedom of functional groups play a critical role in the process of adsorption. As a result, the calculated maximum adsorption capacity of aerogels with free thiourea groups is as high as 719.42 mg/g, and although the reusability of adsorbents decreases with the increase of recycle times, caused by the generation of Au (0) during adsorption process, its adsorption capacity is till as high as 461.9 mg/g. Alternatively, incineration is also a feasible approach, especially after several recycle times, because of the low cost of fabricated adsorbents. Therefore, aerogels prepared by structural design have advantages in the field of gold recovery, and the superior performance also demonstrates the significance of utilization of introduced functional groups in the designed adsorbents.
研究领域:
材料科学
·
环境科学
✓ 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）