ZEITSCHRIFT FUR KRISTALLOGRAPHIE-NEW CRYSTAL STRUCTURES
·
2022
·Vol. 238
·期 1
·13-14
·
IF 0.365
Zhihong Zhu,Lilei Zhang
C 14 H 12 BrClN 2 O, monoclinic, P 2 1 / c (no. 14), a = 13.4072(6) Å, b = 8.6103(5) Å, c = 12.3824(6) Å, β = 100.475(4), V = 1405.60(12) Å 3 , Z = 4, R gt
( F ) = 0.0499, wR ref
( F
2 ) = 0.1215, T = 173 K.
研究领域:
化学
·
晶体学
✓ 已验证
DOI
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2024
·
IF 2.5
Yiyin Yang,Lei Zhang,Fansen Meng,Donglin Tang
ZnO is considered to be a good catalyst for the synthesis of polyurethanes (PUs) by alcoholysis of bisureas (BUs). ZnO tends to form Zn(NCO) 2 (NH 3 ) 2 in the presence of urea at high temperature, so does it in the alcoholysis of BUs. Here, attempt is made to understand the role Zn(NCO) 2 (NH 3 ) 2 plays in the alcoholysis of BUs. A loading of Zn(NCO) 2 (NH 3 ) 2 at 5 mol% is found to be sufficient to catalyze the polymerization and the reaction time is greatly cut from 40 h (catalyzed by ZnO) to 26 h, with similar chemical structures and properties. The tensile strength, elongation at break, and toughness for PU–Zn-5 can reach 43.8 MPa, 330%, and 94.0 J cm −3 , respectively. One-pot synthetic strategy is then further introduced to improve the efficiency of the polymerization. Zn(NCO) 2 (NH 3 ) 2 , BU, and PU can be synthesized in one-pot, by adding ZnO, urea, diamine, LiBr, and diol sequentially. The feasibility of this one-pot method is verified, indicated by the similar reaction time, chemical structures, molecular weight, thermal and mechanical properties. This one-pot synthetic strategy offers an efficient way to synthesize PUs directly and simply from urea, diamines, and diols, which is beneficial for improving the molecular diversity of PUs.
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
COMPOSITES COMMUNICATIONS
·
2025
·
IF 7.7
Qinyong Liu,Jingfan Zhang,Ximei Wen,Baozhu Wang,Jun Sun,Hongfei Li,Xiaoyu Gu,Sheng Zhang
This research outlines a strategy to improve both the flame retardancy and water resistance of polyurea (PUA) while largely preserving its mechanical integrity. Aluminum hypophosphite (AHP) was coated by triphenyl phosphate (TPP), and the resultant TPP@AHP exhibited improved compatibility and hydrophobicity. Additionally, ZIF-8@MXene, a nanohybrid material combining a metal-organic framework with MXene (Ti 3 C 2 T x ) sheets, served as both a reinforcing filler and a synergistic flame retardant. The use of 17 wt% TPP@AHP and 1 wt% ZIF-8@MXene in PUA enabled the composite to achieve a UL-94 V-0 rating and to maintain a limiting oxygen index (LOI) of 26.9% even after 7 days of water immersion. Cone calorimetry tests demonstrated that this formulation significantly reduced the peak heat release rate by 70.9%, total heat release by 30.8%, and smoke production by 32.1%. This work provided a feasible solution for preparing PUA composites with durable flame retardancy and qualified mechanical properties.
研究领域:
材料科学
·
防火材料
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2024
·
IF 2.7
Zhangcheng Gao,Lianfang Feng,Xueping Gu,Jintang Duan,Mingzhe Jiang,Cailiang Zhang
The combination of aromatic and aliphatic structures can endow polyurea with distinct performance advantages. A one-step feeding method is used to synthesize linear hybrid aliphatic/aromatic copolyureas by varying the ratio of m -phenylenediamine (MPD) and polyoxypropylenediamine (D2000) reacting with 4,4′-diphenylmethane diisocyanate (MDI). Real-time Fourier-transform infrared spectrometer monitoring reveals that D2000 exhibits higher reactivity than MPD. Consequently, in the MDI/MPD/D2000 system, D2000 initially reacts with MDI to form an isocyanate-terminated prepolymer, which subsequently reacts with MPD. Compared with the two-step feeding method, this approach successfully eliminates biuret formation and enhances tensile strength. Additionally, decreasing the molar ratio of D2000 to MPD ( λ m ) reduces the size and degree of microphase separation in the polyurea by increasing the ordered hydrogen bonding and benzene conjugation, leading to an increase in tensile strength. Specifically, as λ m decreases from 70 mol% to 30 mol%, the degree of microphase separation decreases from 0.47 to 0.2, causing the tensile strength to rise from 28 to 48 MPa. Further reducing λ m to 30 mol% decreases the degree of microphase separation to 0.16, resulting in an increase in tensile strength to 78 MPa.
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
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Yingqi Xia,Lijia Liu,Yudan Wang,Chunhong Zhang,Yawen Liu
CH 3 Hg + in water is a neurotoxin that is difficult to eliminate and is readily absorbed by the human body through food chains. In this study, thioctic acid was grafted onto the surface of NH 2 -MIL-101 via an amidation reaction to prepare an adsorption material for the rapid and effective removal of CH 3 Hg + , which is designated as LA-MIL-101.The synthesis of LA-MIL-101 was confirmed through analyses including FT-IR, XRD, SEM, TGA, and XPS. BET results indicate that the specific surface area of LA-MIL-101 is 464.92 m 2 ·g −1 . The ideal conditions for CH 3 Hg + adsorption were explored by varying environmental factors such as pH, contact time, and temperature. Furthermore, the introduction of sulfur significantly enhanced the adsorption capacity for CH 3 Hg + . Batch adsorption experiments demonstrate that LA-MIL-101 exhibits an exceptionally rapid adsorption rate, achieving over 88.3 % of the total removal rate within just one minute. Additionally, LA-MIL-101 shows remarkable adsorption efficacy across a broad pH range. The adsorption behavior of LA-MIL-101 for CH 3 Hg + aligns with the Elovich and Langmuir models, with a maximum adsorption capacity reaching 1391.77 μg·g −1 . LA-MIL-101 also displays a strong anti-interference capability in environments containing humic acid or Na + . Notably, it maintains high removal efficiency under conditions involving coexisting cations, as well as in simulated surface water, simulated groundwater, and natural seawater. Moreover, LA-MIL-101 demonstrates good stability and recyclability, retaining effective adsorption after five adsorption/desorption cycles. XPS results elucidate the adsorption mechanism of CH 3 Hg + , highlighting interactions with sulfur (S) and nitrogen (N) atoms. Overall, LA-MIL-101 exhibits high practicality and significant potential for application in the emergency treatment of CH 3 Hg + in aquatic environments.
研究领域:
环境科学
·
材料科学
·
毒理学
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2014
·
IF 2.354
Hai-Mu Ye,Ke-Shuo Liu,Qiong Zhou
Study on the structure of PEO–thiourea binary system has been carried out by several groups, but there still remain some questions. In this study, PEO–thiourea complexes with different thiourea fractions were prepared through freeze-drying and characterized by differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD), Fourier transform infrared (FTIR) microscopy and Raman scattering. A new PEO–thiourea complex with EO:thiourea molar ratio of 4:1 (form II) was demonstrated for the first time. Then the phase diagram of PEO–thiourea binary system was improved, containing two particular complexes at thiourea molar fraction of 0.4 (form I) and 0.2 (form II), respectively. Further analysis suggested that PEO–thiourea form II complex adopts orthorhombic unit cell, and probably takes channel structure with two side-by-side parallel PEO chains incorporated inside the thiourea clathrate. The form II complex is quite stable in pure state at room temperature; while gradually convert into from I by solid–solid transformation when a few form I complex serves as nucleator.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE CHEMICAL LETTERS
·
2016
·
IF 1.947
Li-Li Xi,Hong-Bing Ma,Guan-Hong Tao
CdSe/CdS quantum dots (QDs) functionalized by thiourea (TU) were synthesized and used as a fluorescent sensor for mercury ion detection. The TU-functionalized QDs were prepared by bonding TU via electrostatic interaction to the core/shell CdSe/CdS QDs after capping with thioglycolic acid (TGA). It was observed that the fluorescence of the functionalized QDs was quenched upon the addition of Hg 2+ . The quantitative detection of Hg 2+ with this fluorescent sensor could be conducted based on the linear relationship between the extent of quenching and the concentration of Hg 2+ added in the range of 1–300 μg L −1 . A detection limit of 0.56 μg L −1 was achieved. The sensor showed superior selectivity for Hg 2+ and was successfully applied to the determination of mercury in environmental samples with satisfactory results.
研究领域:
分析化学
·
环境科学
✓ 已验证
DOI
高影响因子
ACS Applied Polymer Materials
·
2024
·
IF 4.4
Shangzhong Zhang,Lifeng Yan
Direct conversion of CO2 to polymers, such as polyurea, is an effective approach for CO2 capture and utilization. However, traditional methods involving CO2 and diamine polymerization require high pressures and temperatures (>5 MPa, ∼180 °C) and result in low molecular weight polyurea. A method has been developed to synthesize polyurea directly from CO2 at mild temperature and pressure (0.1–0.5 MPa, 15–90 °C) in a one-step reaction using organic superbases as both catalysts and dehydrants with the formation of DBU-H2O. This process allows for fast polymerization (10–30 min) and yields high molecular weight polyurea (>106 g/mol). The tensile strength of the as-prepared polyurea film reaches 13.5 MPa, which indicates excellent mechanical properties.
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
Journal of Materials Chemistry A
·
2025
·
IF 9.5
Lin Wang,Manman Jia,Hui Jiao,Shukang Ti,Dongmei Yue
Nitrile Butadiene Rubber (NBR) is widely used in aerospace, petroleum exploration, auto parts, and other fields because of its excellent performance. Nevertheless, NBR usually needs to be crosslinked with sulfur or peroxide, which restricts the tensile performance and recyclability of NBR. Herein, a novel strategy was developed to address these issues by introducing dynamic urea bonds into the main chain using a simple, catalyst-free one-pot method. The presence of urea bonds not only provides a large number of hydrogen bonding sites between the molecular chains but also exhibits the remarkable microphase separation properties of thermoplastic elastomers. This approach endows NBR with enhanced dynamic characteristics and significant recyclability. As a result, the as-synthesized multifunctional NBR elastomer (I–A0.5–P0.5) exhibits excellent tensile strength (19.9 MPa), toughness (93.7 MJ m−3), low glass transition temperature (−52 °C), and low compression cold resistance coefficient (0.15 at −55 °C), which are comparable to those of conventionally covalently crosslinked NBR. Importantly, the elastomer can retain its mechanical robustness, chemical structure, and thermal stability after multiple rounds of recycling (after five times of recycling, with a recovery of more than 81%). To broaden the application of NBR products, I–A0.5–P0.5 was crosslinked with sulfur, and its performance was compared with NBR vulcanizates of different acrylonitrile contents. It shows excellent oil resistance and low temperature resistance. Surprisingly, it can also possess the ability to be reprocessed multiple times. This new multifunctional thermoplastic NBR elastomer is of great significance in solving the problem of difficult recycling of traditional NBR and is expected to replace traditional covalently cross-linked NBR.
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
Sustainability
·
2022
·Vol. 14
·期 22
·15290
·
IF 3.889
Jiaqi Bu,Lu Yuan,Hongru Jiang,Chongqing Wang
A novel adsorbent (GO-TOA) was prepared by condensation and self-assembly of graphene oxide (GO) and thiourea, and it was characterized systematically. The results revealed that thiourea has anchored on graphene oxide (GO) successfully. The results showed that GO-TOA had a higher adsorption capacity (641.724 mg/g) and adsorption rate (92.32%) than GO (196.8 mg/g and 65.6%), indicating that the introduction of thiourea greatly improved the adsorption capacity of GO. Adsorption kinetics, adsorption thermodynamics isotherm, and adsorption thermodynamics were used to study the adsorption mechanism. The results show that GO-TOA still has an adsorption rate of 90.44% compared with 0 cycles (92.32), indicating that GO-TOA has good activation and regeneration capacity. In addition, ethanol and dilute hydrochloric acid were used for the desorption of MB, and the effect of desorption was found very well. Through reusability experiments, we also found that GO-TOA has excellent application potential. We believe that GO-TOA will be a potential adsorbent for MB.Keywords:adsorbent;methylene blue;thiourea;graphene oxide;self-assembly
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
TALANTA
·
2020
·
IF 5.339
Bing Qiang Zou,Hong Zhi Zhang,Zhu Fu,Tianrong Zhan,Jian Wang
As an important sulfur compound , thiourea (TU) has caused great concern because of its wide application as well as its serious toxicity and hazard to the environment. Thus, it is necessary to develop a sensitive and selective method for TU analysis. In this work, gold nanorods (AuNRs) acted as an optical probe to realize the sensitive and colorimetric detection of TU. In HCl medium, Fe 3+ at low concentration was difficult to oxide Au 0 to form Au + because of the high redox potential or the positive Gibbs free energy change . However, this process was possible when TU was present since the association constant between Au + and TU is great enough to bind with TU to form a stable complex to further promote the etching of AuNRs, resulting in the lower aspect ratio of AuNRs with the blue shift and intensity decrease in extinction spectra, accompanied by the divisive colors of AuNRs solution or colorful dark-field light scattering imaging of single AuNR. The blue-shift of AuNRs longitudinal plasmon resonance absorption (LPRA) band was proportional to the concentration of TU in the range of 1–250 nM and the limit of detection (3σ/k) was as low as 0.4 nM. In addition, the colorimetric method was proven with high selectivity in the presence of potential interfering compounds, which was successfully applied to the detection of TU in fruit juice samples. This proposed colorimetric method provides a simple, sensitive yet selective measurement tool for TU sensing, which may offer new opportunities in the development of colorimetric sensors for food safety in the future.
研究领域:
分析化学
·
食品安全
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2021
·
IF 5.161
Zhongqun Zhou,Shenye Chen,Xinmeng Xu,Yang Chen,Lanpin Xu,Yanning Zeng,Faai Zhang
Designing a crosslinked polymer with autonomous self-healing at room temperature (RT) remains an arduous challenge because the topological network reconstructions are governed by crosslinking. Herein, a flexible strategy is described to develop intrinsically dynamic crosslinked elastomers with RT self-healing via a photo-initiated copolymerization to address these issues. The key is to incorporate a urea–urethane structure with dynamic urea bond into the polymer network as a flexible crosslinking unit. This strategy endows the crosslinked elastomer with superior properties, including autonomously rapid self-healing at RT, extreme stretchability of up to 1726%, high toughness (∼24.45 MJ m –3 ), extended stability, and recyclability. Upon damaged, the resultant elastomers instantly self-heal at RT and completely self-heal within 10 min without the assistance of external triggers. These amazing properties of the dynamic elastomer are attributed to the synergistic effect of the robustly dynamic urea bonds and inter- and intrachain hydrogen bond interactions. Notably, the self-healing and mechanical properties of the network can be optimized by tuning the dynamic crosslinker content. Dynamic reversibility occurs at RT evidenced by rheological tests. The facile fabrication method and multifunctional properties of the self-healable and stretchable crosslinked elastomer demonstrate that it shows great potential in smart protective coating and wearable electronics industry.
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）