POLYMER DEGRADATION AND STABILITY
·
2019
·
IF 3.78
Shengnan Li,Ling Zhong,Shuo Huang,Dingfei Wang,Fengxiu Zhang,Guangxian Zhang
A novel flame-retardant ammonium salt of cholamine (methylenephosphonic acid) ethylene-organic phosphate acid (ACMPEP) with reactive -P O(ONH 4 ) 2 and OH groups was synthesized and characterized using nuclear magnetic resonance spectroscopy . The flame retardant not only could be grafted onto cotton fibers through P O C covalent bonds , but also react with each other to form poly-ACMPEP. The results showed that the finished cotton fabrics have excellent flame retardance, good stiffness and durability. The limiting oxygen index (LOI) value of 30% ACMPEP-treated cotton was 42.0%, and after 50 laundering cycles, the LOI value still had 30.0%. Thermogravimetric analysis (TGA) results showed that the decomposition temperature of treated cotton fibers in N 2 and air was 253 °C and 247 °C, lower than that of the control cotton fibers. Additionally, thermogravimetric-Fourier transform infrared (TG-FTIR) spectroscopy analysis indicated that the treated cotton fibers only released little combustible volatile during the thermal pyrolysis process. The cone calorimetry results showed that the heat release rate (HRR) and the total heat release (THR) of treated cottons were much lower than those of control cottons. The bending length increased 44.8% for the cotton fabric treated with 30% ACMPEP. The scanning electron microscopy (SEM) and the X-ray diffraction suggested that the finishing process only slightly affected the cotton fiber structure. The FTIR spectroscopy analysis confirmed the cross-linking reaction between ACMPEP molecules and cellulose . The tensile strengths of the finished cotton fabrics decreased a little. Together, the results suggested that the ACMPEP-treated cotton fabrics have excellent flame retardance and durability.
研究领域:
材料科学
·
纺织工程
✓ 已验证
DOI
高影响因子
Petroleum Science
·
2024
·
IF 6
Zhe Xu,Jin-Sheng Sun,Jing-Ping Liu,Kai-He Lv,Xiao-Dong Dong,Zong-Lun Wang,Tai-Feng Zhang,Yuan-Wei Sun,Zhi-Wen Dai
As drilling wells continue to move into deep ultra-deep layers, the requirements for temperature resistance of drilling fluid treatments are getting higher and higher. Among them, blocking agent, as one of the key treatment agents, has also become a hot spot of research. In this study, a high temperature resistant strong adsorption rigid blocking agent (QW-1) was prepared using KH570 modified silica, acrylamide (AM) and allyltrimethylammonium chloride (TMAAC). QW-1 has good thermal stability, average particle size of 1.46 μm, water contact angle of 10.5°, has a strong hydrophilicity, can be well dispersed in water. The experimental results showed that when 2 wt% QW-1 was added to recipe A (4 wt% bentonite slurry+0.5 wt% DSP-1 (filtration loss depressant)), the API filtration loss decreased from 7.8 to 6.4 mL. After aging at 240 °C, the API loss of filtration was reduced from 21 to 14 mL, which has certain performance of high temperature loss of filtration. At the same time, it is effective in sealing 80–100 mesh and 100–120 mesh sand beds as well as 3 and 5 μm ceramic sand discs. Under the same conditions, the blocking performance was superior to silica (5 μm) and calcium carbonate (2.6 μm). In addition, the mechanism of action of QW-1 was further investigated. The results show that QW-1 with amide and quaternary ammonium groups on the molecular chain can be adsorbed onto the surface of clay particles through hydrogen bonding and electrostatic interaction to form a dense blocking layer, thus preventing further intrusion of drilling fluid into the formation.
研究领域:
石油工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2024
·
IF 4.3
Yuncai Gao,Yu-e Shi,Feiyang Cheng,Chao Huang,Zhenguang Wang
The selective detection of acrylamide (AA) is crucial, which is limited by the high background and interferences from food matrix. A room temperature phosphorescence (RTP) assay was developed through modulating its RTP by a stepwise rigidification strategy. The first step rigidification resulted in crosslinking of AA and denser of hydrogen bonding. This prompted the RTP efficiency from <0.1 to 3.8 % and emission lifetime of AA (from 3.0 μs to 0.29 s). Introducing boric acid resulted in the second step rigidification, triggered the formation of rigid matrix and chemical bonding. These synergistic effects prompted the photoluminescence quantum yield to 23.7 % and emission lifetime to 1.20 s. AA was quantitatively detected through monitoring the RTP intensity, with a limit of detection of 0.9 μg/mL. Benefiting from the delayed signal detection, background signal and the interferences from food matrices were eliminated, endowing the detection of AA in practical food samples.
研究领域:
食品科学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Materials Today Communications
·
2024
·
IF 3.7
Lechen Yang,Yong Li,Dajun Huan,Hewen Zhang,Chunling Zhu
Epoxy resin (EP) is usually brittle because of highly cross-linked chemical structure , so it is necessary to carry out research on toughening of epoxy resin. Here, a modified epoxy resin with enhanced mechanical toughness and strength was prepared using a novel modifier (PEA-BA), synthesized from polyetheramine D-400 (PEA) and benzoic acid (BA). Polyether chains that represent flexible structures, and aromatic rings representing rigid structures, were integrated together into the modifier to achieve simultaneous enhancement of the toughness and strength of the resulting epoxy resin. Moreover, the aromatic rings in PEA-BA formed π-π interactions with the aromatic rings in the EP network, further increasing the ductility of the modified epoxy resin. Research results demonstrated that the modified epoxy resin exhibited significantly improved elongation at break (increasing from 6.7 % to 39.2 %), as well as higher tensile strength (from 61.9 MPa to 69.3 MPa) and impact strength (from 25.3 kJ·m −2 to 62.9 kJ·m −2 ). Importantly, the glass transition temperature and thermal stability of the modified epoxy resin were not markedly reduced. The above properties indicated that PEA-BA achieved a favorable combination of high strength and ductility of epoxy resin, providing a new idea for toughening epoxy resin.
研究领域:
材料科学
·
化学工程
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产品关联
DOI
高影响因子
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
·
2020
·Vol. 646
·期 15
·1309-1314
·
IF 1.24
Yan Zhang,Jing Fan,Lingzhi Chen,Na Liu,Hongmei Geng
Two new tetranuclear cluster-based compounds, namely [Cd 2 (L1)(H 2 O)(DMA)] n ( 1 ) and [Cd 2 Ba 2 (L2)(H 2 O) 6 (DMA)] n ( 2 ) [H 4 L1 = 3-(3',5'-dicarboxylphenoxy) phthalic acid, H 4 L2 = 6-(3',4'-dicarboxyl-phenoxy) isophthalic acid, DMA = N,N' -dimethylacetamide], were successfully synthesized under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction analyses. Compound 1 features a two-dimensional (2D) layered framework with tetranuclear [Cd 4 (COO) 6 ] clusters as building subunits, and can be simplified into a binodal (3, 6)-connected kgd topological network with the schläfli symbol of {4 3 } 2 {4 6 ;6 6 ;8 3 }, and compound 2 features a three-dimensional (3D) complicated framework based on heterometallic tetranulear [Cd 2 Ba 2 (COO) 8 ] cluster subunits, and can be simplified into a binodal (3, 6)-connected topological network. In addition, compounds 1 and 2 not only have high thermal stabilities but also show strong luminescent emissions at room temperature.
研究领域:
无机化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2022
·
IF 10.508
Gaochao Liu,Maxim S. Molokeev,Zhiguo Xia
Broadband near-infrared (NIR) light sources based on phosphor-converted light-emitting diodes (pc-LEDs) are desirable for biochemical analysis and medical diagnosis applications; however, the development of target NIR phosphor is still a challenge. Herein, broadband NIR phosphors, Cr3+-activated CaSc1–xAl1+xSiO6 (λem = 950 nm), are designed and optimized by chemical substitution toward enhanced quantum efficiency and thermal stability. Structural and spectral analyses along with density functional theory calculations reveal that Sc3+/Al3+ substitution contributes to enhancing the structural rigidity and the local symmetry of the [Sc/AlO6] octahedron so that the nonradiative relaxation of Cr3+ emission centers is suppressed significantly. The as-fabricated phosphor-in-glass-based NIR LED light source demonstrates great potential in the detection of alcohol concentration. This study provides a local structure design principle for exploring NIR phosphors with enhanced thermal stability and will also stimulate further studies on material discovery and quantitative analysis of NIR spectroscopy.
研究领域:
材料科学
·
光学工程
·
生物医学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC
·
2015
·
IF 2.128
Hui Fei,Gang Xu,Jian-Ping Wu,Li-Rong Yang
DERA SEP (2-deoxy- d -ribose-5-phosphate aldolase cloned from Staphylococcus epidermidis ) shows higher catalytic activity toward 2-deoxy- d -ribose-5-phosphate (DRP) than that of DERA ECO (2-deoxy-ribose aldolase cloned from Escherichia coli ). However, the acetaldehyde tolerance of DERA SEP is still at low level, which limits its use in large-scale applications. Although the mechanism responsible for enzyme inactivation in the presence of solvents is unclear, earlier work indicated the positive correlation between the tolerance of an enzyme for organic solvents and the rigidity of its structure. The acetaldehyde tolerance of DERA SEP was improved by site-directed mutagenesis on the basis of enhancing the rigidity of the protein structure. After calculating the virtual mutation energy (stability) of the enzyme and experimental verification, variant 10 mutant DERA SEP with three amino acid substitutions (T120C, G174I, and G213C) was harvested after three rounds of site-directed mutagenesis. It showed surprisingly high tolerance to acetaldehyde, with almost 70.5% residual catalytic activity after exposure to 300 mM acetaldehyde for 2 h, while the wild-type DERA SEP retained only 11.3% activity under the same condition. Because the rigidity of the protein was increased after incorporating the mutations, the specific activity of the variant 10 was only half that of DERA SEP . Thus, the acetaldehyde tolerance of DERA SEP was efficiently increased by enhancing the rigidity of the structure. These results suggested that the inactivation of DERA by exposure to acetaldehyde may result from protein structural damage.
研究领域:
生物化学
·
酶工程
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产品关联
DOI
高影响因子
Advanced Optical Materials
·
2024
·
IF 8
Peiran Xie,Pan Wang,Jiaqian Zhou,Zhu Guo,Lingling Mao
0D organic–inorganic antimony halides have attracted increasing attention due to the non-toxicity, high stability, and superior photoluminescence quantum yield (PLQY). Here, a series of hybrid antimony chlorides with the same organic cation ethyltriphenylphosphonium (Ph 3 EtP + ), including non-emissive (Ph 3 EtP) 2 Sb 2 Cl 8 and nine (Ph 3 EtP) 2 SbCl 5 -based emissive compounds, are synthesized and characterized. These emissive compounds are namely, the guest-free (Ph 3 EtP) 2 SbCl 5 and (Ph 3 EtP) 2 SbCl 5 ·guest (guest = glycol, acetic acid, methanol, ethanol, n-propanol, i-propanol, acetone, and acetonitrile). The solvent used can alter the coordination mode of Sb because the solvation effect affects the reactivity of the anions ([SbCl 4 ] − and Cl − ), leading to the formation of either A 2 Sb 2 Cl 8 or A 2 SbCl 5 . The solvents can be even incorporated into the crystal structure, where stronger interaction with [SbCl 5 ] 2− leads to higher temperature of the escape of the solvent. The guest molecules could increase the structural rigidity of [SbCl 5 ] 2− via hydrogen bonding and dipole–dipole interactions, which tends to reduce the room-temperature photoluminescence (PL) Stokes shift and temperature-dependent PL shift by decreasing the [SbCl 5 ] 2− deformability, along with enhanced PLQY from 81% in guest-free to near-unity in (Ph 3 EtP) 2 SbCl 5 ·glycol. This work shows that targeted synthesis and diversified choices of solvents provide an efficient tool to generate steady variations in hybrid emissive materials for optoelectronics.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
ACS Applied Polymer Materials
·
2024
·
IF 4.4
Yiyuan Sun,Zenghui Yang,Liming Tao,Qihua Wang,Xinrui Zhang,Yaoming Zhang,Tingmei Wang
It remains a challenge to balance the trade-off between toughness, stiffness, and shape memory properties in shape memory epoxy resins (SMEP). In this study, we employed molecular engineering to synthesize stiff–flexible SMEP, by reacting furan-containing epoxy monomers 2,5-bis[(2-epoxymethoxy)methyl]furan (BOF), derived from biomass, with amines containing imine-amine (IA) and 4,4′-dithiodiphenylamine (4-DTDA). The results indicate that the sacrificial hydrogen bonding and the necessary flexible segments confer BOF/4-DTDA/IA (BDI) with a toughness of up to 13.9 MJ/m3 and a stiffness of 3.5 GPa. Furthermore, the introduction of hyperbranched epoxy resin (HER) yields BOF/4-DTDA/IA/HER (BDIH), which maintains a stiffness exceeding 2 GPa while retaining a toughness of 11.2 MJ/m3. Additionally, BDIH exhibits enhanced tensile strength with an increasing strain rate, which we rationalize based on the loss modulus and scanning electron microscopy morphology analyses. The collaborative motion of the rigid–flexible chain segments and the hydrogen bonding contributes to BDI’s excellent shape memory performance (shape fixation ratio (Rf = 99.00%) and shape recovery ratio (Rr = 99.15%). The physical barrier effect and flexibility of the HER further enhance the shape memory properties. In conclusion, the mechanical features and shape memory performance of BDI and BDIH demonstrate the significant potential for applications in smart molds, smart devices, and other advanced technologies.
研究领域:
材料科学
·
分子工程学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF BIOTECHNOLOGY
·
2025
·
IF 3.9
Yuwen Wei,Fulong Li,Yukun Zheng,Youxiang Liang,Yan Du,Huimin Yu
Transaminases have important applications in the synthesis of drug intermediates such as chiral amines. However, natural transaminases exhibit suboptimal thermal stability, limiting their further applications. Building upon an Rhodobacter sp. -derived ( R )-selective transaminase ( Rb TA), we report a dual-region coupling engineering approach to improve thermostability of Rb TA by strengthening the core hydrogen-bond networks and rigidifying the flexible surface loop. Through single strategy, we identified 4 thermostability improved single mutations, among which I249Q demonstrated the most substantial improvement, achieving a 18-fold increase in half-life ( t 1 / 2 40 ) and a 11.2 ℃ increase in T 50 10 . Then in strategic coupling, the synergistic effect of dual-region modification was observed in both thermal stability and activity enhancement, as mutant with the best high-temperature catalytic performance, R136P/F228Y, had its T 50 10 improved by 7.1℃ and exhibited a 4.2-fold increase in k cat / K m towards ( R )-3-amino-1-butanol. Finally, R136P/F228Y achieved a 20.5 % improvement in conversion over WT in an analytical-scale synthesis in 72 h at a 5 ℃ elevated catalytic temperature. Molecular dynamics simulations demonstrated that the synergy of the formation of new hydrogen bonds and decrease in flexibility accounted for the thermostability improvements. This study provides guidance for enhancing thermostability of similar fold-type enzymes without impairing enzymatic activity in an efficient manner.
研究领域:
生物化学
·
蛋白质工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2022
·
IF 5.895
Hongyan Yang,Lan Wang,Libo Yuan,Heng Du,Boyuan Pan,Kui Lu
A series of hybrid peptides were designed by connecting an antimicrobial peptide Ce(1–8) with a lipopolysaccharide (LPS)-targeting peptide Lf(28–34) via different linkers. Antimicrobial experimental results indicated that linkers play an essential role in the anti-Gram-negative bacterial activity of the hybrid peptides. Among these hybrid peptides, peptide CL5 with dipeptide rigid linker LP exhibited excellent activity and selectivity against Gram-negative bacteria. The minimum inhibitory concentrations of CL5 against the tested Gram-negative bacteria were 4–32 μM, while the toxicity toward HEK-293 cells was relatively low. It was found that the interactions of the peptides with LPS were crucial for peptide activity against Gram-negative bacteria. Antimicrobial mechanistic studies showed that peptide CL5 contributed to the death of Gram-negative bacterial cells by disrupting the integrity of the bacterial membranes. This study revealed the importance of linker selection in the design of hybrid peptides and provides the basis for the further development of antimicrobial peptides.
研究领域:
微生物学
·
药物化学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
DALTON TRANSACTIONS
·
2015
·Vol. 44
·期 37
·16486-16493
·
IF 4.197
Aixiang Tian,Yali Ning,Yang Yang,Xue Hou,Jun Ying,Guocheng Liu,Juwen Zhang,Xiuli Wang
By using mixed rigid and flexible organic ligands, three Keggin based compounds, [Ag6(tbz)4(bmz)2(H3PW12O40)]·4H2O (1), [Ag(H2bdpm)2(H2PMo12O40)]·7.5H2O (2), and [Ag4(tbz)2(H2bdpm)2(HPMo12O40)]·2H2O (3) (Htbz = thiabendazole, Hbmz = benzimidazole, H2bdpm = 1,1′-bis(3,5-dimethyl-1H-pyrazolate)methane), were hydrothermally synthesized and structurally characterized. Through adopting rigid Htbz ligands, compound 1 with hexa-nuclear AgI clusters has been obtained. These hexa-nuclear clusters are linked by Keggin anions alternately to form a one dimensional (1D) chain. In compound 2, the organic moiety is the flexible H2bdpm ligand. The Keggin anions are fused by [Ag(H2bdpm)2]+ subunits to form a 1D chain. In compound 3, the rigid Htbz and the flexible H2bdpm cooperate to modify the anions. Two tbz and two H2bdpm are fused by four AgI ions to construct a tetra-nuclear AgI cycle. The anions connect these cycles through Ag–O bonds alternately to form a 1D chain. Adjacent chains arrange parallel to build a 2D layer. The chains in the adjacent layers are vertically packed and linked by Ag–O bonds to construct a 3D framework. The electrochemical and photocatalytic properties of the title compounds have been studied. Furthermore, we have also studied the Hg2+ recognition properties in a suspension of compounds 1 and 3.
研究领域:
无机化学
·
材料科学
·
分析化学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）