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
·
化学工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Wu Bin Ying,Haixiong Liu,Peiyuan Gao,Zhengyang Kong,Han Hu,Kai Wang,Ang Shen,Zhijin Jin,Lin Zheng,Hongxia Guo,Ruoyu Zhang,Jin Zhu
Considering the complicated environment in daily use of stretchable devices, the capabilities of anti-stress relaxation, anti-fatigue, anti-fungal and self-healing are very much appreciated, and the above four functionalities largely depend on the elastic matrix. Here, these demands are fulfilled by a poly(thiourethane-urethane) elastomer CBPU-3. In detail, a large amount of cyclohexane rings, with completely reversible boat–chair conformational transition, are introduced into the backbone of poly(thiourethane-urethane), and such non-planar ring imparts molecular elasticity and modulus into the elastomer, resulting in remarkable anti-stress relaxation and anti-fatigue abilities. Even after 20 h fixation at 300% strain and 1000 times cyclic tensile (50% strain), the recovery ratio could still be higher than 98%, and its stable microstructure is proved by SAXS scattering patterns. In addition, the thioether bond ensures the effective mildew proof ability, and the mechanical properties and transmittance change little even after a severe mildew pollution for 30 days. Simultaneously, the relatively lower bond energy of C-S (62.0 Kcal/mol) in thiourethane bonds endowes the poly(thiourethane-urethane) with self-healing capability (highest: 40 μm/min at 80 °C). Finally, the durability and usability of the deformable resistive sensor array based on this elastomer as the matrix are drastically enhanced due to the above integrated functionalities.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2024
·
IF 5.1
Dongfei Zhang,Ao Wang,Wenkai Liu,Ao Zhen,Jiehua Li,Feng Luo,Xianglong Han,Zhen Li,Hong Tan
The reported dynamic covalent bonds (DCBs) exhibit certain drawbacks, including sluggish reaction rates and high dissociation temperatures, which impede the reusability of DCBs cross-linked polymers. Herein, we develop a kind of imidazole-urea bond (IUBs) through the rapid self-catalytic reaction between imidazole and isocyanate without additional catalysts. The IUBs are found to be highly reversible via a thermally dissociative mechanism while also demonstrating an irreversible exchange with amines. Then, histamine (1H-imidazole-4-ethanamine) is first employed as a chain extender to construct IUBs in the synthesis of novel imidazole-based cross-linked polyurethane-ureas (IMCPU). The IMCPU can undergo multiple recyclings of melt processing and be aminolyzed even at room temperature. Given the wide availability of the commodity histamine, IMCPU exhibits great potential for broad applications in the fields of dynamic materials.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2020
·
IF 5.918
Cheng-Jie Fan,Zhi-Bin Wen,Zhi-Yuan Xu,Yi Xiao,Di Wu,Ke-Ke Yang,Yu-Zhong Wang
Currently, a variety of elastomers with a self-healing capacity and reprocessability have been developed by dynamic chemistry to extend the service life, increase the reliability of polymeric materials, and reduce the waste. However, it is still a large challenge to seek an appropriate dynamic interaction that may perfectly match the general performance of the target polymeric materials such as polyurethane. Herein, we report a poly(thiourethane-urethane) (PTUU–Nx) elastomer containing dynamic thiourethane bonds prepared via a thiol–isocyanate click reaction, which is stable at room temperature, healable at moderate temperature, and reprocessable at high temperature. Importantly, it exhibits a mechanical strength similar to the polyurethane because of a very similar structure. The dynamic feature of PTUU–Nx is demonstrated theoretically and experimentally to originate from the exchange of thiourethane bonds via the reversible generation of isocyanates and thiols. Most importantly, the thiourethane bond possesses a much lower bond dissociation energy than the urethane bond, which not only makes PTUU–Nx elastomers easier to be reprocessed but also endows them with a desirable self-healing ability under moderate conditions. In addition, the optimized sample PTUU–N2 is utilized to fabricate a conductive device by coating Ag glue on the elastomer surface and inserting the coated elastomer into a circuit, which displays a high self-healing efficiency, as the material recovers to its original mechanical property and conductivity. Therefore, these results not only indicate that the PTUU–Nx elastomers have considerable potential for applications in intelligent electronic devices but also provide new ideas for developing new self-healing materials by applying the adaptable dynamic bond to the target polymers.
研究领域:
材料科学
·
高分子化学
·
智能材料
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·
IF 2.7
Shan Jiang,Tianyi Han,Tongshuai Tian,Chuanqing Yang,Li Liu
Compared with isocyanate-based polyurethanes (PUs), poly(hydroxyurethane)s (PHUs) are more likely to form phase mixing structure, inducing poor elastic properties. To avoid this, stronger interaction between hard segments is required. Herein, carbon dioxide-based poly(hydroxyurethane-urea)s (PHUUs) with different hard segment contents were prepared through polyaddition reaction using 5-membered dicyclic carbonate (BADC) as hard segment, poly(propylene glycol) bis(2-aminopropyl ether) (D2000) as soft segment, and amino-terminal polyurea oligomer (HMDA*) chain extender, and several PHUs were prepared by using hexamethylenediamine (HMDA) chain extender or without using chain extender as controls. The interaction between hard segments were strengthened with the introduce of chain extender. Compared with PHUs, PHUUs with HMDA* chain extender were more inclined to form significant microphase separation. For PHUUs, the hard segment T g appeared at around 60°C when hard segment content reached 40 wt%, and the interdomain spacings were in the range of around 14–23 nm with 40–50 wt% hard segment content. In addition, PHUUs exhibited better solvents resistance and mechanical properties than PHUs with the same hard segment content. PHUUs with certain hard segment content showed good elastic recovery, with a residual strain less than 2% after 10 cycles, which comparable with conventional isocyanate-based PUs.
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
MOLECULES
·
2022
·Vol. 27
·期 17
·5527
·
IF 4.927
Qi Chen,Baole Li,Junli Wang,Haowei Zhu,Xiwen Chen,Yifu Hu,Jia Zhou,Xiang Li,Weifang Zheng,Taihong Yan
The use of tetra-alkylcarbamides as novel ligands: N,N-butyl-N’,N’-hexylurea (L1: ABHU), and N,N-butyl-N’,N’-pentylurea (L2: ABPU), for the solvent extraction and complexation behaviors of uranium(VI) was synthesized and investigated in this study. The effects of HNO3and NO3−concentrations in the aqueous phase on the distribution ratio of U(VI) were examined. Under 5 mol/L HNO3concentration,DUreached 5.02 and 4.94 respectively without third-phase formation. During the extraction, slope measurements and IR spectral analysis revealed that the U(VI) complexes are a form of UO2(NO3)2·2Lfor both ligands. In addition, thermodynamic studies showed that the uranium extraction reaction was a spontaneous exothermic reaction. The deep structural analysis of the complexes was realized with DFT calculation. The bond length, bond properties, and topology of the complexes were discussed in detail to analyze the extraction behavior. This study enriches the coordination chemistry of U(VI) by tetra-alkylcarbamides, which may offer new clues for the design and synthesis of novel ligands for the separation, enrichment, and recovery of uranium in the nuclear fuel cycle.Keywords:uranium;extraction;tetra-alkylcarbamides;DFT calculation
研究领域:
化学
·
核化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2025
·
IF 9.8
Lijun Wei,Bixiao Zhou,Mengdie Cai,Xinyu Wang,Guowen Zhang,Xianglei Cheng
Ethylene thiourea (ETU) and propylene thiourea (PTU), the degradation products of dithiocarbamates, are carcinogenic, teratogenic, and mutagenic. In this study, we developed an ultrasensitive method for the simultaneous detection of ETU and PTU using amidated carbon quantum dots (A-CDs) as chemiluminescent probes. The distinctive chemiluminescence (CL) mechanisms of the A-CDs were elucidated using CL spectroscopy, radical trapping experiments, and mass spectrometry. ETU or PTU are oxidized by Ce(IV) resulting in the formation of sulfur-based free radicals. Then the radicals are selectively recognized by the A-CDs accompanying with CL emission. The high-performance liquid chromatography-CL method was validated by quantifying ETU and PTU in vegetables, wherein the detection limit was 0.17 μg·kg −1 . Comparing with previous literatures, the proposed method demonstrated advantages with lower solvent use, shorter detection time, reduced matrix effects, higher accuracy and precision. The results indicated that ETU was really detected in tomatoes, implying the potential risk of public health.
研究领域:
分析化学
·
食品安全
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYTICA CHIMICA ACTA
·
2016
·
IF 4.712
Hao-Hua Deng,Guo-Lin Hong,Feng-Lin Lin,Ai-Lin Liu,Xing-Hua Xia,Wei Chen
Herein, we reported for the first time that gold nanoparticles-catalyzed 3,3′,5,5′-tetramethylbenzidine-H 2 O 2 system can serve as an ultrasensitive colorimetric pH indicator. Gold nanoparticles acted as a catalyst and imitated the function of horseradish peroxidase . The absorbance at 450 nm of the yellow-color product in the catalytic reaction exhibited a linear fashion over the pH range of 6.40–6.60. On the basis of this property, we constructed a novel sensing platform for the determination of urea, urease , and urease inhibitor. The limit of detection for urea and urease was 5 μM and 1.8 U/L, respectively. The half-maximal inhibition value IC 50 of acetohydroxamic acid was found to be 0.05 mM. Urea in human urine and urease in soil were detected with satisfied results.
研究领域:
生物化学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RENEWABLE ENERGY
·
2021
·
IF 8.001
Changzhong Chen,Rong Chen,Tangyuan Zhao,Linge Wang
To reveal the influence of organic polymer supports on the properties of shape stabilized phase change materials (ssPCMs), a linear polyurea (LP) and crosslinked polyurea (CP) were synthesized for stabilizing polyethylene glycol (PEG) for thermal energy storage . Though the surface area of LP are about 25 times of that of CP, the shape stability of CP for melt PEG is better than that of LP. Due to the crosslinked network, CP has much stronger interactions with PEG, which could promote the adsorption capacity of PEG. The highest PEG loading capability of LP and CP without liquid leakage above melting point is 70 wt% and 80 wt% respectively, and the corresponding melting enthalpy is 95.42 J/g and 107.60 J/g respectively. However, the heat storage efficiency of PEG/LP ssPCMs is higher than that of PEG/CP ssPCMs with the same PEG content, which caused by the weak restrictions of free movement of PEG chains from LP. Both types of ssPCMs exhibit good reusability from thermal cycle test and good thermal stability from thermal analysis, and the thermal conductivity of ssPCMs can effectively enhance after adding some carbon materials. The study supplied an inspiration to select proper polymer matrix for ssPCMs.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2022
·
IF 10.319
Jiawen Sun,Chao Liu,Jizhou Duan,Jie Liu,Xucheng Dong,Yimeng Zhang,Ning Wang,Jing Wang,Baorong Hou
A novel silicone-based poly(urea-thiourea)/tannic acid composite (PDMS-P(Ua-TUa)-TA) with excellent mechanical, self-healing and antifouling properties is developed. The multiple dynamic hydrogen bonds formed by thiourea groups, urea groups, and tannic acid (TA) molecules ensured a tough elastomer (ultimate strength: 2.47 MPa) with high stretchability (∼1000%). TA molecules as partial hydrogen bonding cross-linking sites interacted rapidly with urea and thiourea groups before the migration of polymer chains, resulting in fast and efficient self-healing. Scratches on the film completely disappeared within 12 min, and the repair efficiency of strength was up to 98.4% within 3 h under ambient condition. Self-healing behavior was also evaluated in artificial seawater and the healing efficiency (HE) was 95.1%. Furthermore, TA uniformly dispersed in the polymer matrix provides good antibacterial and anti-diatom properties, as well as strong adhesion to the substrate (∼2.2 MPa). Laboratory bioassays against marine bacteria adhesion (∼96%, ∼95% and ∼93% reduction for P. sp., E. coli , and S. aureus , respectively) and diatom attachment (∼84% reduction) demonstrated an outstanding antifouling property of the PDMS-P(Ua-TUa)-TA. This work provides a promising pathway towards the development of high-performance silicone-based coatings for marine anti-biofouling.
研究领域:
材料科学
·
海洋生物学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2017
·
IF 2.843
Xubao Jiang,Xiaoli Zhu,Alexandre A. Arnold,Xiang Zheng Kong,Jerome P. Claverie
Owing to the presence of abundant interchain interactions such as hydrogen bonds, polyureas (PU) are only swellable or soluble in a limited number of highly protonic solvents, and the viscosity of the solutions obtained is very high, making their chemical structure characterization hard or even impossible by standard NMR. Accurate structure analysis is also hard by solid-state NMR due to low spectral resolution. The presence of a side reaction in their synthesis generating biuret cross-links is often invoked to explain their insolubility. Here we demonstrate that High Resolution Magic Angle Spinning (HR-MAS) NMR is an efficient tool for the chemical structure analysis even for cross-linked PU. With 1H, 13C, and 1H–15N HSQC combined, a variety of linear and cross-linked PU is analyzed by HR-MAS NMR, and conclusive information on their chemical structure is obtained, which reveals for the first time that the biuret group is absent in all PU.
研究领域:
材料科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2021
·
IF 4.094
Zhongqun Zhou,Yanning Zeng,Caili Yu,Quanyang Li,Faai Zhang
The development of self-healing elastomers with superior physical properties is a challenging task. Herein, we present a design concept for a self-healing, highly stretchable, and robust poly(urethane–urea) elastomer prepared via a thiol-ene click reaction by a facile one-pot in situ photopolymerization method. The objective of the utilized approach is to incorporate weak noncovalent H-bonds, dynamic covalent urea bonds, and products of a thiol-ene click reaction into a polymeric backbone. This study also applies polytetramethylene ether glycol domains as soft segments to facilitate the polymeric chain diffusion and dynamic exchange reaction. Owing to these unique molecular characteristics, the resultant elastomer possesses a uniform structure and versatile properties, such as high stretchability corresponding to a maximum strain of 464%, ultimate tensile strength of 10.9 MPa, self-recoverability, high self-healing efficiency of 99%, high recyclability, and good weldability . Upon rupture, the as-prepared elastomer completely restores its original mechanical properties after heating to 80 °C for 5 h. The dynamic reversibility of the elastomer is evidenced by stress relaxation analysis and rheological testing. In addition, it can be effectively encapsulated and potentially used for fabricating self-healing stretchable conductive devices.
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
危险品化学品经营许可证（带存储）