THERMOCHIMICA ACTA
·
2023
·
IF 3.5
Yongchen Zhu,Jianwei Zhang,Weidong He
5-Amino-1H-tetrazole (5-ATZ), an environmentally friendly energy-containing material for new propellants, is gradually applied in high-energy propellants and its ionic salt compounds have received wide attention. This study focused on investigating the interaction mechanism of guanidinium-5-aminotetrazole (GA) and nitrocellulose (NC) by kinetic methods and TG-DSC-FTIR analysis. DSC and TG experiments indicated that there was a certain interaction during the pyrolysis process of NC and GA. Comparing the kinetic models of NC and peak 3 in NC-GA, it can be found that the addition of GA mainly affected the m-value and contribution in the second step B→C, and the mechanism function changed from F n to C n,m. TG-DSC-FTIR experiments indicated that the initial decomposition product of NC, NO 2 , participated in the thermal decomposition process of GA, and the two reacted chemically to form CO, N 2 O, which made NO 2 unable to completely oxidize the skeleton of NC to produce CH 2 O, HCOOH.
研究领域:
化学
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材料科学
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能源与推进剂研究
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DOI
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2023
·Vol. 148
·期 21
·12049-12057
·
IF 4.4
Zhang Ming,Zhao Fengqi,Jiang Yifan,Li Na,Li Hui,An Ting,Qin Zhao,Jiang Zhoufeng
Various graphene-salen iron nanocomplex S-551-Fe, S-602-Fe, S-902-Fe, S-590-Fe, S-792-Fe and S-550-Fe were successfully synthesized using different coupling agents. The microstructure, composition and structure of the prepared graphene-salen iron nanocomplex were characterized by SEM, EDS, FTIR, XPS and RAMAN routes. The results showed the successful fabrication of graphene-salen iron nanocomplex and their two-dimensional structure. In addition, the catalytic property of the graphene-salen iron nanocomplex on the pyrolysis property of TKX-50 was investigated via DSC method, and the kinetic data was calculated by linear and nonlinear models. The positive effects of the synthesized graphene-salen iron nanocomplex for TKX-50 pyrolysis were confirmed, and the impact on the second pyrolysis procedure of TKX-50 is more significant. Among the nanocomplex considered, the S-551-Fe has better catalytic property for TKX-50 pyrolysis, and the activation energy ( E a ) of TKX-50 decreased from 163.50 to 135.55 kJ·mol −1 in the conversion degree of 0.2 ~ 0.8. In addition, the catalytic mechanism of preferred S-551-Fe for TKX-50 pyrolysis was disclosed via in situ FTIR and gas phase MS methods. This study is helpful to the precise design of graphene iron coordination catalysts and the disclosure of their catalytic mechanism for TKX-50 pyrolysis.
研究领域:
材料化学
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含能材料
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催化化学
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热分析
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纳米复合材料
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物理化学
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DOI
高影响因子
POLYMER BULLETIN
·
2019
·Vol. 77
·期 6
·2855-2871
·
IF 1.858
Zhang Yongjie,Fan Mingshuai,Li Xiaopei
Abstract Long-chain alkyl silicone is a type of modified silicones that finds potential applications in various areas. Long-chain alkyl fluorosilicone (LCAFS) can be considered as a modified long-chain alkyl silicone as it synergistically combines the properties of long-chain alkyl silicone and novel fluorosilicone. As far as we know, reports on the synthesis of LCAFS are rare. In this report, a facile method to synthesize LCAFS was explored. It was found that silicone bearing novel C30-45 alkyls and trifluoropropyl pendent groups, namely (C30-45 alkyl) methylsiloxane/trifluoropropylmethylsiloxane copolymer (TF-AMS), could be synthesized via a simple siloxane equilibration process between silanol-terminated polytrifluoropropylmethylsiloxane and (C30-45 alkyl)methyl silicone, a commercially available silicone that is generally considered as unreactive. The chemical structure of TF-AMS was characterized unambiguously by FTIR, NMR, GPC and DSC. The thermal stabilities of TF-AMS were investigated by TGA. Based on our experimental results, a plausible mechanism for the synthesis of TF-AMS was proposed. Graphic abstract A novel long-chain alkyl fluorosilicone was synthesized via a simple yet efficient siloxane equilibration process.
研究领域:
材料科学
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化学工程
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高分子化学
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 22
·52263
·
IF 3.057
Jie Zhang,Zongwei Guo,Jinpeng Ma,Lingxiao Song,Guorui Yang,Yuhui Ao,Lei Shang,Ming Li
As an important thermosetting resin, epoxy resin (EP) is widely used in the field of composite materials. Long storage time, rapid curing and low viscosity of one-component EP is ideal for preparing composite materials by vacuum assisted resin transfer molding (VARTM). For this sake, we developed and synthesized a new imidazole thermal latent curing agent, 4,7-diimidazol-2,1,3-benzothiadiazole (BTD-MZ 2 ) with a yield of about 75%. The curing behavior, thermal stability and storage time of the prepared EP system was studied by differential scanning calorimeter (DSC), thermal gravimetric analyzer (TGA), modular compact rheometer (MCR), respectively. DSC results showed that EP/17.5 wt% BTD-MZ 2 had a good latent period at low temperature, and can rapidly cure EP when heated to 150°C. TGA results show that BTD-MZ 2 promoted the formation of carbon residue and the residual carbon rate of EP/17.5 wt% BTD-MZ 2 is as high as 37.9%. MCR results show that the storage time of EP/17.5 wt% BTD-MZ 2 at 60°C can reach 850 min. In addition, it could play a role of catalyst used as co-curing agents with aromatic amines for EP. DSC test showed that the addition of 5 wt% BTD-MZ 2 reduced the activation energy of EP/4,4′-diaminodiphenylmethane (DDM) and promoted the curing reaction.
研究领域:
材料科学
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化学工程
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高分子科学
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DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2021
·
IF 6.165
Qingguo Zhang,Sihan Feng,Xinyuan Zhang,Ying Wei
Two novel ionic-liquid-based binary mixture systems of N,N-diethyl-N-(2-methoxyethyl)- N -methylammonium tetrafluoroborate ([DEME][BF 4 ]), or N,N-diethyl- N -methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl)imide ([DEME][TFSI]) + γ-butyrolactone (GBL) are prepared over the whole concentration range (mole fraction from 0–1). Some important thermodynamic properties and parameters of the pure ILs and two systems were measured and calculated. The temperature dependences of the transport properties (viscosity and conductivity) were described by the Vogel–Fulcher–Tamman (VFT) equation. The excess molar volumes ( V E ) were obtained from the experimental densities and fitted to Redlich–Kister (R–K) polynomial equation. The DSC analysis, the shifts of the infrared (IR) spectrum, and COSMO–RS methodology based on DFT calculations were combined to explain the interaction information of GBL molecules and cations/anions of the selected systems. The stable optimized structures, interaction energies, and charge distributions were further obtained. Those maybe slight enlighten the application of similar mixture systems in future.
研究领域:
化学
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材料科学
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DOI
高影响因子
Food Bioscience
·
2025
·
IF 5.9
Walaa Kobacy,Xiaomin Gong,Naglaa K.F. Elshamandy,Hamdy A. Zahran,Ahmed I. Osman,Ahmed K. Rashwan
The study explored the chemical, antimicrobial, and antioxidant properties of essential oils from garlic (GEO), parsley (PEO), and thyme (TEO) using GC-MS, ATR-FTIR, and DSC techniques, and examined the synergistic effects of their combination on antioxidant and antimicrobial properties. The oils' antimicrobial effectiveness against pathogens was also tested. GC-MS analysis revealed diverse chemical profiles. The garlic, thyme, and parsley mixture (GTP) showed the highest phenol content (533.05 milligrams of gallic acid equivalent per 100 grams of dry weight sample), flavonoids (284.16 milligrams of quercetin equivalent per 100 grams of dry weight sample), and antioxidant activity (94.14% DPPH scavenging). The oils demonstrated significant antimicrobial effects, particularly against gram-negative bacteria and molds, with the GTP mixture being highly effective against Aspergillus niger . The bioactive compounds and antimicrobial effects were ranked as GTP > GT > GP > TP > GEO > TEO > PEO. These findings suggest that combining these EOs enhances their bioactivity, positioning them as natural preservatives for food safety and shelf-life extension.
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DOI
高影响因子
Brazilian Journal of Pharmaceutical Sciences
·
2023
·
IF 1.3
Yang Xintong,Chen Yang,Qiao Ning
In this study, we investigated the effects of polymers on the pharmaceutical cocrystal formation process. Ibuprofen (IBU) was selected as the active pharmaceutical ingredient (API), nicotinamide (NIC) and saccharin (SAC) as the cocrystal coformer (CCF), ethanol/water as the solvent, polyvinylpyrrolidone (PVP) and poly (ethylene glycol) (PEG) as the representative polymers. We prepared IBU-NIC and IBU-SAC cocrystals in ethanol-water cosolvent in the absence or presence of polymers. Cocrystal screening products were characterized by FTIR, DSC, PXRD, and HPLC. The results showed that the mixture of IBU and IBU-NIC cocrystal can be prepared in ethanol-water cosolvent without polymers. The addition of PVP facilitates the formation of pure IBU-NIC cocrystal; however, no cocrystal was formed in PEG solutions. SAC could not cocrystallize with IBU in the ethanol-water solvent in the absence of polymers. Neither PVP nor PEG could facilitate the formation of the IBU-SAC cocrystal.
研究领域:
药剂学
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材料科学
·
化学
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Xianbao Li,Shunjing Luo,Yaqin Hou,Yunfei Liu,Xiuting Hu,Chengmei Liu
This study aimed to reveal the effect of corn oil on formation of complex between rice starch and fatty acids, including lauric acid (C12:0), myristic acid (C14:0), palmitic acid (C16:0) and stearic acid (C18:0). The RVA, XRD, DSC and CLSM analysis confirmed formation of starch-fatty acid complex but the starch-triglyceride complex was not detected. The addition of triglyceride promoted formation of starch-C16:0 and starch-C18:0 complexes, which might be due to more leached amylose induced by oil. However, triglyceride inhibited formation of starch-C12:0 and starch-C14:0 complexes, which might be due to high solubility of C12:0 and C14:0 in oil. In conclusion, the effect of triglyceride on formation of starch-fatty acid complex depended on the chain length of fatty acids.
研究领域:
食品科学
·
化学
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Rong Zhang,Teng Jin,Yue Zhang,Xueqing Sui,Shiman Wu,Yue Wu,Dapeng Hao,Zhenwei Yao,Zhengze Yu,Xuejun Liu,Hua Zhang
Immunotherapy holds significant promise to completely eliminate tumor, yet lack of timely evaluation of immune responses, which challenged by inherent lagging and pseudoprogression during immunotherapy. Immune-vascular crosstalk (IVC), an enhancement ring for the mutual regulation linking tumor vascular normalization with immune remodeling forms, emerging as a systematic indicator for immunotherapy outcomes, necessitates timely, non-invasive, and early detection of its status to enhance clinical benefits. Herein, positive and negative loop models of tumor IVC were established using different degree of photothermal therapy (PTT) based on NaBiF 4 :Gd@PDA@PEG nanoprobes. Multi-functional magnetic resonance imaging, including fast spoiled gradient-recalled (FSPGR), time-resolved imaging of contrast kinetics (TRICKs) and dynamic susceptibility contrast perfusion weighted imaging (DSC-PWI), was applied to dynamically reflect normalized/ablated tumor vasculature, well-matched increased/decreased immune response corresponding to different status of IVC, confirmed by pathology results. This study proposes a novel biological method to noninvasively detect the positive/negative IVC loop, paving the visualized way for immunotherapy assessed benefits, which is expected to be extended to clinical translation.
研究领域:
肿瘤学
·
免疫学
·
医学影像学
·
纳米技术
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产品关联
DOI
高影响因子
THERMOCHIMICA ACTA
·
2019
·
IF 2.251
Hao Wang,Zichao Guo,Wanghua Chen
Optimization of the kinetic parameters with thermal analysis data is an essential issue. In this work, the conjugate direction particle swarm optimization (CDPSO) approach, as a global stochastic optimization algorithm that is suitable to high-dimension optimization problem, is first employed to estimate the kinetic parameters with DSC data. This algorithm combines the global optimization ability of the particle swarm optimization (PSO) and the ability to escape from the local extremum by the conjugate direction algorithm (CD) to find the globally optimal solutions. This algorithm does not require estimation of the initial values of the kinetic parameters. The validation of this method is verified by two cases: DCPO decomposition and CHP decomposition. By comparing the experimental and calculated heat flow results, the accuracy of the fitted kinetic parameters is verified. These two cases prove the effectiveness of CDPSO algorithm in the estimation of high-dimension kinetic parameters using DSC data.
研究领域:
热分析
·
优化算法
·
材料科学
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DOI
高影响因子
Polymers
·
2024
·Vol. 16
·期 23
·3254
·
IF 4.7
Jiaqi Wang,Zhaoyutian Chu,Sijia Zheng
Considering the demand for the construction of a sustainable future, it is essential to endow the conventional thermoset silicone adhesive with reuse capability and recyclability. Although various research attempts have been made by incorporating reversible linkages, developing sustainable silicone adhesives by natural linkers is still challenging, as the interface between the natural linker and the silicone is historically difficult. We exploited the possibility of utilizingα-lipoic acid, a natural linker, to construct a sustainable silicone adhesive. Via the simultaneous ring-opening reaction between the COOH and epoxide-functionalized silicone and the polymerization of theα-lipoic acid, the resulting network exhibited dynamic properties. The shear strength of the LASA90 presented strong adhesion (up to 88 kPa) on various substrates including steel, aluminum, PET, and PTFE. Meanwhile, reversible adhesion was shown multiple times under mild heating conditions (80 °C). The rheology, TG-DTA, DSC, and1H NMR showed that the degradation of the LASA occurred at 150 °C via the retro-ROP of the five-membered disulfide ring, indicating their recyclability after usage. Conclusively, we envision that a silicone adhesive based onα-lipoic acid as a natural linker is more sustainable than conventional silicone thermosets because of its desired properties, strong adhesion, reversibility, and on-demand heat degradation.
研究领域:
材料科学
·
化学工程
·
可持续发展
·
粘合技术
·
聚合物化学
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产品关联
DOI
PubMed
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2022
·Vol. 24
·期 34
·20073-20081
·
IF 3.945
Ruifen Shi,Fengyi Zhou,Yu Chen,Zhenghui Liu,Shuzi Liu,Tiancheng Mu
Deep eutectic solvents (DESs) are well-known as novel solvents due to their unique properties, which are indispensable for the development of green chemistry in the future. CoCl2·6H2O and NiCl2·6H2O-based DESs, which could be called magnetic DESs (MDESs) for short in view of their responsive behavior to an external magnetic field, have been widely used in many industrial applications, such as biomass treatment, electrolytes, and material preparation. For better application and full-scale development of these MDESs in various fields, eleven MDESs were prepared in this work by using CoCl2·6H2O and NiCl2·6H2O as hydrogen bond acceptors (HBAs) with alcohols, carboxylic acids and amides as hydrogen bond donors (HBDs), respectively. The intermolecular interactions between the components of MDESs were characterized via FTIR, 1H NMR and DSC analysis. In addition, physicochemical properties including density, viscosity, conductivity, ionicity, pH values, surface tension, thermostability and solvatochromic parameters were investigated. All MDESs exhibit acid characteristics and have good conductivity comparable with ionic liquids (ILs) and other DESs used for electrolytes. The results show that stronger H-bonding networks in Ni-based MDESs make them have higher density, viscosity, polarity and surface tension values than Co-based MDESs. Moreover, all prepared MDESs possess a good conductivity behavior which could be comparable to that of common organic solvents and ILs. According to this work, we could better comprehend the behavior of Co/Ni-based MDESs and choose the appropriate one for particular applications.
研究领域:
化学
·
材料科学
·
绿色化学
·
工业应用
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DOI
高影响因子
危险品化学品经营许可证（带存储）