JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Tiantian Ping,Yu Dong,Shufeng Shen
Nonaqueous CO 2 absorbents, composed of secondary alkanolamines and 2-alkoxyethanols, have attracted much attention for an energy-efficient CO 2 capture process. In this work, densities and viscosities of partially CO 2 -loaded mixtures of 2-(butylamino)ethanol (BAE) + 2-butoxyethanol (EGBE) and 2-(ethylamino)ethanol (EAE) + EGBE were measured at atmospheric pressure over the temperature range of (293.15 to 353.15) K with amine mass fraction ( w 1 ) of (0.10, 0.30 and 0.50) containing various CO 2 loading. With increasing CO 2 loadings, significant increases in both density and viscosity were observed. Dimensionless ρ loaded · ρ CO2-free −1 and η loaded · η CO2-free −1 from the CO 2 -free and CO 2 -loaded systems were fitted by proposed correlations as a function of temperature, amine concentration and CO 2 loading. The calculated values of density and viscosity from the correlations are in good agreement with the experimental results, with AADs within 0.15% and 1.60% for density and viscosity respectively. The dramatic increase in viscosity of carbonated solutions was interpreted by the intermolecular interactions and the formation of ionic products in the mixtures based on the FTIR spectral results.
研究领域:
化学工程
·
物理化学
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF PHARMACEUTICS
·
2016
·
IF 3.994
Chenguang Wang,Wei Xiong,Sathyanarayana Reddy Perumalla,Jianguo Fang,Changquan Calvin Sun
Dihydromyricetin (DMY) is a natural flavanol compound isolated from a traditional Chinese medicine , Ampelopsis grossedentata . Despite that optically pure (+)DMY is desired for treating chronic pharyngitis and alcohol use disorders, only DMY racemate is commercially available due to prolonged exposure time to high temperature and the presence of metal ions during industrial extraction, which cause racemization of the homochiral (+)DMY. We have developed an extraction method for successfully obtain optically pure (+)DMY. We have further assessed the physicochemical properties of the two phases using PXRD, DSC , TGA, FTIR, and moisture sorption. Among them, PXRD and FT-IR are suitable for quickly distinguishing homochiral (+)DMY from racemic (±)DMY. Lastly, with the aid of cocrystallization with theophylline , the absolute configuration of homochiral (+)DMY was identified to be (2R, 3R).
研究领域:
药学
·
化学
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DOI
PubMed
高影响因子
Polymer Chemistry
·
2013
·Vol. 4
·期 21
·5401-5406
·
IF 5.231
Shengjie Ling,Zeming Qi,David P. Knight,Zhengzhong Shao,Xin Chen
As in other polymer blends, the phase behavior of silk fibroin (SF) blends with other polymers is thought to be important for their related properties. Here we used FTIR imaging to study the phase behavior of three silk protein-based polymer blends, silk fibroin/chitosan (SF/CS) blend, silk fibroin/sodium alginate (SF/SA) blend, and silk fibroin/polyvinyl alcohol (SF/PVA) blend. FTIR images of the films prepared from these polymer blends indicated that the SF/CS blend was compatible, the SF/SA blend was partially compatible, and the SF/PVA blend was incompatible. The results accord with the conclusions from the conventional analysis methods like SEM, DSC, and DTMA reported in the literature. Moreover, we show that FTIR images of the blends can provide additional useful information on the composition of the individual components, and the conformation of SF at defined locations with a spatial resolution of 4 μm. Therefore, we believe FTIR imaging is a useful technique to better understand both the chemical and physical properties of silk protein-based polymer blends, and other kinds of polymer blends.
研究领域:
高分子科学
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材料科学
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光谱学
·
生物聚合物
·
成像技术
✓ 已验证
DOI
高影响因子
IRONMAKING & STEELMAKING
·
2026
·
IF 2.1
Jiawen Chen,Liang Yu,Shipeng Xu,Yu Wan
As a crucial functional material in the continuous casting process, mould fluxes play a significant role in ensuring smooth operation and improving the quality of cast billets. To mitigate the environmental impact of fluorides in mould fluxes, TiO2 has been introduced as a network former to reduce viscosity and melting temperature. The formation of perovskite instead of cuspidine also contributes to controlled heat transfer. However, preventing the formation of titanium carbide (TiC) under high-temperature conditions remains challenging. Experimental results indicate that during heating, both CaO–SiO2–TiO2 and CaO–SiO2–CaF2–TiO2 slag systems react to form perovskite. TiO2 participates more readily in solid-state reactions with CaO than CaF2 does, thereby inhibiting the formation of cuspidine. Furthermore, in carbon-containing CaO–SiO2–TiO2 systems, TiC forms along with CO at elevated temperatures. It is revealed that TiC formation does not result from the direct reaction between TiO2 and C, but rather from the reaction between CaTiO3 and C. Under high-temperature carbon-rich conditions, carbon reduces perovskite to form TiC. Consequently, in contrast to fluorine-based fluxes, titanium-bearing mould fluxes require careful optimisation of carbon content to prevent TiC precipitation.
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DOI
高影响因子
RSC Advances
·
2020
·Vol. 10
·期 31
·18192-18199
·
IF 3.119
Zihao Yang,Taiheng Yin,Fengfan Zhang,Wei Wu,Meiqin Lin,Zhaoxia Dong,Juan Zhang
To study the microscopic dispersion state of CO2 in different ester solvents, the solubility, volume expansion coefficients and in situ Fourier transform infrared (FTIR) spectra of the CO2–ester system were measured. The results show that the solubility and expansion coefficient of CO2 in ester solvents decreases as the hydrocarbon chain increases. As the pressure increases, the infrared absorption peaks of CO2 and the functional groups characteristic of ester molecules shift, indicating that CO2 molecules interact with ester molecules and that CO2 would destroy the interactions between the ester molecules. The hydrocarbon chain length of the ester molecules has a significant effect on the infrared absorption peak of the CO2–ester system. As the hydrocarbon chain length increases, the CO2 absorption peak shift and peak shift of the carbonyl groups in the ester gradually decrease.
研究领域:
化学工程
·
物理化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2024
·Vol. 31
·期 7
·1-11
·
IF 2.6
Yang Rui,Dai Zilin,Kong Zhenxing,Ou Juhua
Procuring silicone rubber composite with different content of vinyl MQ silicone resin was prepared and its thermal stability was evaluated. A total of 50 wt% MQ resin containing 5 wt% vinyl MQ exhibited optimal thermal stability and was consequently chosen. This silicone rubber composite was blended with TPU at high temperature using an internal mixer to produce a modified TPU. The TPU modified by silicone rubber was firstly investigated by Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA). The FTIR results indicated that negligible chemical reactions occurred between TPU and silicone rubber during the mixing process. Furthermore, the TGA results demonstrated that the silicone rubber composite positively influenced the thermal stability of TPU. Additionally, the modified TPU displayed satisfactory thermal stability even after aging. Moreover, Scanning Electron Microscope (SEM) results indicated that uniform dispersion of silicone rubber was facilitated by the banburying method. The tensile strength of modified TPU initially increased and then decreased when the content of silicone rubber reached 3 wt%. On the other hand, the elongation at break of modified TPU demonstrated continuous improvement. Furthermore, the mechanical properties of the modified TPU were still acceptable after aging.
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 SCIENCE AND TECHNOLOGY
·
2022
·
IF 2.799
Qingxia Ye,Zhen Li,Jin Liu,Di Wang,Ping Wang,Xianbiao Wang,Xianhai Hu
In this paper, the application of zone smelting to remove the trace heavy metal lead from waste acrylonitrile-butadiene-styrene (wABS) plastics was investigated. ABS standard samples with uniform and stable lead content were prepared by the method of lead stearate coupling agent. The structure, thermal stability, morphology and lead content of the standard ABS samples before and after zone smelting were characterized by FTIR, DSC, SEM and ICP-AES. The results showed that the lead content in the front and middle sections of the ABS sample decreased obviously after zone smelting, while the lead content in the tail increased significantly, and the structure, thermal stability and morphology remained basically unchanged.
研究领域:
材料科学
·
环境工程
·
分析化学
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产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Haipeng Zhang,Jun Tang,Jihong Fu,Boshen Wang,Junli Yu,Xakura Xarpby,Xinyue Li
Recently, the pollution problem of microplastics (MPs) that are widespread in various foods has drawn widespread attention; yet, much remains unknown regarding the presence of MPs in ice cream. In this study, nine different brands of commercial ice cream from China were detected, and the presence of MPs was analyzed. After a two-step digestion with 10% KOH + 30% H 2 O 2 , a total of 1031 MPs were extracted and characterized. MPs were detected in all brands of ice cream. The results revealed that the maximum and minimum quantities of MPs detected in the tested samples were 241 ± 24 MPs/100 g (sample E) and 38 ± 6 MPs/100 g (sample C), respectively, with an average concentration of 131 ± 22 MPs/100 g. The Kruskal-Wallis test revealed a statistically significant difference in MPs abundance among the samples (p = 0.003). Fiber was the main shape, and the results of micro-Fourier transform infrared spectroscopy (μ-FTIR) showed that the most common polymer of MPs in ice cream was rayon. The smallest size of the MPs recorded was 22 μm, while the largest size exceeded 2128 μm. Therefore, the findings of the study revealed information about the present situation and contamination of MPs in ice cream.
研究领域:
环境科学
·
食品安全
·
分析化学
·
污染研究
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DOI
高影响因子
ANALYST
·
2014
·Vol. 139
·期 8
·1967-1972
·
IF 3.906
Chao Yan,Bin Yang,Zhicheng Yu
Silk fibroin extracted from the gland of Bombyx mori silkworm is employed as an ideal system to investigate its conformation transition in methanol/D2O solution. The transition process was monitored by Fourier transform infrared (FTIR) spectroscopy coupled with terahertz time domain spectroscopy (THz-TDS). Analysis of FTIR spectra suggests that, with increasing time of treatment, an increasing band at 1634 cm−1 is observed indicating the formation of β-pleated sheets coincident with the loss of intensity of a band at 1673 cm−1 indicating decrease of the random coil structure. In addition, there is a burst phase of 33% occurring during the first 2 minutes when the gland fibroin membranes are immersed into methanol/D2O solution. THz spectra present distinct features for conformations of silk fibroin, in combination with the results obtained from FTIR; the peaks observed at 1.54 THz (51 cm−1), 1.67 THz (55 cm−1), and 1.84 THz (61 cm−1) can be attributed to a β-pleated sheet, α-helix, and random coil, respectively. Intensity change of bands centered at 1.54 THz and 1.84 THz confirms the formation of the β-pleated sheet and the disappearance of the random coil. Kinetic curves obtained from THz spectra indicate that the methanol-induced conformation transition from the random coil to the β-pleated sheet is fitted with an exponential function. The results suggest that THz-TDS presents great potential as a complementary approach in studying the secondary structure of a protein, providing significant insight into the silk-spinning process in vivo.
研究领域:
生物物理学
·
材料科学
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DOI
PubMed
高影响因子
International Journal of Electrochemical Science
·
2023
·Vol. 8
·期 12
·12735-12740
·
IF 1.5
Binbin Zhang,Yuan Zhou,Xiang Li,Xiufeng Ren,Hongen Nian,Yue Shen,Qiang Yun
FTIR (Fourier transformed infrared) spectra have been collected and analyzed for solutions of lithium tetrafluoroborate in propylene carbonate (PC). It has been shown that the carbonyl stretch, symmetric ring deformation stretch and ring deformation stretch bands for PC is very sensitive to the interaction between Li + and the solvent molecule. Their half-peak breadth increases and bands split with the addition of LiBF 4 , indicating that a strong interaction exists between Li + and PC molecule mainly through the oxygen group of C=O and ring position of PC.
研究领域:
物理化学
·
光谱学
·
电解质溶液
·
电池材料
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DOI
高影响因子
VIBRATIONAL SPECTROSCOPY
·
2020
·
IF 1.917
Ren Hu,Cheng Zong,Long-xiang Lin,Ting Wei,Qian Cheng,Yan-xia Jiang,Chang-jian Lin,Bin Ren,Zhong-qun Tian
A facile Fourier transform infrared (FTIR) spectroscopy is developed to detect live cell activities in the transmission mode. With the use of an O ring to aid cell culture on optical windows, live cell activities can be semi-quantitatively investigated using a commercially available demountable liquid device by FTIR spectroscopy in the transmission mode. Cellular volume adaptation to osmolarity was observed by FTIR spectra for PC12 cells. The chemical information upon growth of human cervical cancer cell line, HeLa cells, were investigated by FTIR at interval incubation time. Glycogen enrichment concurring with cell proliferation was illustrated, but the dissipation of glycogen upon subculturing is to be understood. Further comparison of the CaSki cells with its counterpart Ect1/E6E7 cells revealed bands features for the discrimination of the two cell types. These results demonstrate that the developed protocol can be complementary to microincubators and facilitate chemical analyses of live cellular activities by FTIR spectroscopy in the transmission mode.
研究领域:
生物化学
·
细胞生物学
·
医学检测
✓ 已验证
DOI
高影响因子
POLYMER ENGINEERING AND SCIENCE
·
2026
·
IF 3.6
Xiaoru Wang,Guoxuan Ma,Li Zhou,Lipeng Sang,Shuang Li,Jianru Wang,Bo Yuan,Xueren Wang,Chunxiang Li
Changes in chemical bonds driven by combined thermo-oxidative aging and mechanical loading directly influence the structural integrity of hydroxyl-terminated polybutadiene (HTPB) propellants. Due to uncertainties surrounding the chain scission mechanism of HTPB subjected to thermo-oxidative aging, and the confounding effects of concomitant cross-linking and chain scission on experimental measurements and data interpretation, the present work identifies urethane cross-links as characteristic recognition sites. In situ infrared spectroscopy is utilized to systematically probe chemical bond evolution of HTPB elastomers under static thermo-oxidative aging as well as thermo-oxidative aging coupled with mechanical stress. At the early stage of thermo-oxidative aging, the hydrogen-bond network of urethane groups breaks down first. Bond scission takes place simultaneously across the soft and hard segments of HTPB polyurethane, producing large quantities of amide groups ( CONH ) via oxidative rearrangement. However, secondary cross-linked structures possess limited stability and fully degrade via hydrolysis, oxidation and chain cleavage at the late aging stage. Scission of long molecular chains into shorter segments alters the modulus contributions of chemical cross-linking and physical entanglement. Chemical cross-linking modulus peaks at week six, while physical entanglement modulus maximizes at week eight. When subjected to coupled thermal, humid, oxidative and mechanical fields, stress changes the degradation pathways of HTPB polyurethane. In HTPB soft segments, it mainly causes conformational rearrangement, mechanochemical chain scission and formation of new unsaturated groups. For polyurethane hard segments, stress mainly promotes fatigue degradation and bond scission. This work reveals the microscopic causes behind mechanical property evolution and provides theoretical basis for predicting the service life and optimizing anti-aging formulations of HTPB propellants. Highlights Hydrogen-bond networks and dual-segment chain of HTPB preferentially fracture. Oxidation and chain scission remove secondary cross-links of aged HTPB. Shortened molecular chains alter the modulus of aged HTPB. Mechanical loading alters the thermo-oxidative degradation pathways of HTPB. External loading accelerates bond rupture within hard-segment domains of HTPB.
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DOI
高影响因子
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