COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2014
·
IF 2.354
Yajie Jiang,Tao Geng,Qiuxiao Li,Guojin Li,Hongbin Ju
The salt-free catanionic surfactant dodecyltrimethylammonium decanoate (DTAD) was synthesized by a novel method. Phase behavior and phase structure of DTAD with water at full concentration range were studied at 20–45 °C, using differential scanning calorimetry (DSC), freeze-fracture transmission electron microscopy (FF-TEM), polarization microscopy, and small-angle X-ray diffraction (XRD) techniques. The DTAD–water system formed a large aqueous multi-phase region, a large lamellar liquid crystal (L α phase) region, and a hydrated crystal phase. The densely packed vesicles and the lamellar structure induced the formation of aqueous multi-phase region. With increasing temperature, the multi-phase region and the L α phase region reduced, and the isotropic solution phase (L 1 phase) appeared.
研究领域:
表面化学
·
胶体科学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2024
·
IF 5.1
Jianfei Xia,Lingling Ni,Chang Zeng,Bao Wang,Rui Zhang,Chenxuan Sun,Jian Song,Junfeng Liu,Chengtao Yu,Ying Zheng,Pengju Pan
Terephthalic polyesters are important engineering plastics and can crystallize into multiple crystal phases, including the mesophase in processing. However, the formation process and structural characteristics for the unique long-range ordered mesophase of terephthalic polyesters are still not well understood. Herein, we investigated the crystal polymorphism, crystallization kinetics, phase transition, and mechanical properties of a medium-chain terephthalic polyester, poly(hexamethylene terephthalate) (PHT). A new long-range ordered mesophase (named as the δ phase) is discovered for PHT during quiescent melt crystallization at a low crystallization temperature (Tc = 10–30 °C). However, the α and β crystal phases are crystallized at a medium (40–80 °C) and high (90–130 °C) Tc, respectively. The mesomorphic δ phase has a long-range order with a layered structure and inclined chain packing, which shows faster chain relaxation and smaller lamellar thickness than the α and β phases. The mesomorphic δ phase is metastable and converts into the stable β phase upon heating or high-temperature annealing. Mechanical properties of PHT can be well tuned by crystal polymorphs. The mesomorphic δ phase of PHT has good transparency and ductility, while the α and β phases possess a higher yield strength and modulus. This work provides an in-depth understanding of the mesophase formation and complex crystal polymorphism of terephthalic polyesters.
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
RSC Advances
·
2015
·Vol. 5
·期 43
·34451-34455
·
IF 3.84
Yu Liu,Weidong Chi,Hui Liu,Yueyang Su,Liang Zhao
Cubic and tetragonal ZrO2 were synthesized by a sol–gel method using ethanol and glycerol as solvents and ZrOCl2·8H2O as zirconium source. The effect of phase stabilization with amorphous carbon was observed and discussed. The structural evolution, phase transformation and morphological characteristics of powders were investigated by thermogravimetric analysis (TG), differential scanning calorimetric analysis (DSC), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Cubic and tetragonal phase could be generated in this system.
研究领域:
材料科学
·
陶瓷学
✓ 已验证
产品关联
DOI
高影响因子
TALANTA
·
2025
·
IF 6.1
Ruifang Ding,Sheng Liu,Yangyang Zhang,Zhen Li,Ying Zuo,Dong Pei,Tao Lan,Jinxia Hu,He Zhu,Mei Lv,Litao Wang
The separation and analysis of complex samples with wide polar range on a singular column is always a difficult problem in separation and analysis science. In this study, the RCC3-R molecular cage modified with the quaternary ammonium salt stationary phase (RCC3-GQ@silica) was successfully prepared and applicated in the separation of wide polar range compounds. In the Reverse Phase Liquid Chromatography (RPLC) mode, due to the hydrophobicity and π-π interactions provided by the cyclohexane and benzene rings in the molecular cage structure, this stationary phase demonstrated effective separation capabilities for alkylbenzenes, polycyclic aromatic hydrocarbons, phenols, and anilines. In the Hydrophilic Interaction Liquid Chromatography (HILIC) mode, the study explored the separation performance of this stationary phase for sugars and inorganic salts. Utilizing a mixed mode of HILIC/RPLC/Ion Exchange Chromatography (IEC), effective separation was achieved for sulfonamides, nucleosides, acids, and amino acids, indicating good separation effects for medium to strongly polar compounds as well as various hydrophilic compounds. Combining various separation modes, the RCC3-GQ@silica stationary phase successfully separated 91 compounds across 15 categories. These results not only demonstrate the potential of the stationary phase in expanding the range of polarities of analyzable compounds and achieving multipurpose use on a single column, but also confirm its effective separation of nucleosides in pure water systems, further emphasizing the significant application potential of RCC3-GQ@silica stationary phase in the field of green chemistry.
研究领域:
分析化学
·
分离科学
·
绿色化学
✓ 已验证
DOI
PubMed
高影响因子
ANALYTICA CHIMICA ACTA
·
2015
·
IF 4.513
Qing Wang,Mao Ye,Li Xu,Zhi-guo Shi
A mixed-mode chromatographic packing material, C18 and diol groups modified silica (C18-Diol), was prepared with controllable hydrophobicity and hydrophilicity . It demonstrated excellent aqueous compatibility and stability in aqueous mobile phase ; compared to the traditional C18 column, improved peak shape of basic analytes was also obtained. Additionally, it exhibited both reversed-phase liquid chromatographic (RPLC) and hydrophilic interaction chromatographic (HILIC) performance; the analyte separation scope was thus enlarged, demonstrated by simultaneous separation of twenty acids, bases and neutrals. More interestingly, a novel on-line two-dimensional liquid chromatography on the single column (2D-LC-1C) was established by modifying the high performance liquid chromatographic instrument only with the addition of an extra six-port two-position valve. The early co-eluted components of the extract of Lonicera japonica on the 1st-dimension (RPLC) were collected for the online re-injection to the 2nd-dimension (HILIC) by conveniently varying the mobile phase components. Six more peaks were obtained. The established system was simple, easy operation and low cost, which had advantages in analyzing complicated samples.
研究领域:
分析化学
·
药物分析
·
色谱技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TRIBOLOGY INTERNATIONAL
·
2025
·
IF 6.9
Weihua Cao,Xiaolong Ma,Xiao Yang,Yiwei Guo,Changxin Liu,Yu Dong,Xiaowen Qi
Three-phase coupled composites were manufactured to holistically evaluate their load-response mechanisms. Tribological properties in ball-on-disk tests were correlated with GF content and different applied loads. Tribological properties of embedded semirings were better than polymer semirings in semiring tests, resulting in the decrease of COF by 44 %, and the reduction in wear depth by 98.8 %. Embedded semiring with the inclusion of 3 wt% GF possessed remarkable tribological properties, as evidenced by COF of 0.071 and wear rate of 22.7 × 10 −4 mm/h. Stress and strain distributions, as well as associated coupling mechanism among all three phases are revealed with the aid of FEA and MD simulation. Overall, this study offers a fundamental theoretical of polymer composites for self-lubricating bearings applications.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SEPARATION SCIENCE
·
2017
·Vol. 41
·期 4
·877-885
·
IF 2.557
Dan Liu,Ting Qiao,Haiyan Liu,Xiaoling Wang,Zhi-guo Shi
In the present study, a polar-embedded reversed-phase liquid chromatographic stationary phase that contained internal sulfone groups was prepared. The synthesis involved the “thiol-ene” click chemistry between the vinyl functionalized silica and 1-octadecanethiol, followed by the oxidization of sulfide to sulfone groups. The resulting material simultaneously possessed the alkyl chain, i.e. C18, and the internal sulfone groups. Elemental analysis demonstrates that the element contents of the C18/sulfone silica were C 8.94%, H 1.87% and S 0.66%. Chromatographic evaluations indicate that the C18/sulfone stationary phase exhibited a little less retention than the C18/sulfide one. A comparable chromatographic performance of neutral analytes was obtained on these two columns, but much better chromatographic performance in the case of basic and acid analytes was obtained on C18/sulfone stationary phase with additional features such as lower silanol activity, better stability (stable working conditions of pH 1.0–10.0), and better compatibility with 100% aqueous mobile phases. The batch-to-batch reproducibility was acceptable (the RSDs of retention times for the probes were no higher than 1.73%), demonstrating the suitability of the applied synthetic strategy for the new stationary phase. The C18/sulfone is a promising polar-embedded RPLC stationary phase.
研究领域:
分析化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOM
·
2021
·Vol. 73
·期 12
·4376-4386
·
IF 2.474
Zou Qi,Le Qichi,Chen Xingrui,Ban Chunyan,Jia Yonghui,Guo Ruizhen,Wang An
This work investigated the corrosion resistance of AZ80 (Mg-8Al-0.5Zn alloy) with different Nd contents in alkaline solution by the mass loss test, electrochemical test, scanning electron microscope, energy spectrum analysis, and x-ray diffraction. To remove the influence of the Mg 17 Al 12 phase, alloys were heat treated at 410°C for 10 h. Results revealed that Al 2 Nd and AlMnNd phases mainly exist in the alloy. The corrosion rate of the alloy increased when the Nd content was < 0.4 wt.% because the Al 2 Nd phase formed galvanic corrosion with the Mg matrix. With the increase of Nd content, AlMnNd phase appeared in the alloys, which decomposed during the corrosion process and formed a good protective film to reduce the corrosion rate.
研究领域:
材料科学
·
腐蚀工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2024
·
IF 3.8
Xiang Wang,Xingrui Wang,Hanqi Yang,Hanlin Zeng,Zhiqiang Xu,Wenhao Chen,Guangming Zhou,Jingdong Peng
In this study, we synthesized and employed an ionic gel-functionalized silica stationary phase for high-performance liquid chromatography. The successful fabrication of the stationary phase was confirmed through attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), zeta-potential measurements, and elemental analysis (EA). Comparative performance evaluation against a commercial column demonstrated the prepared column's effectiveness in the mixed mode of reversed-phase liquid chromatography (RPLC), hydrophilic interaction liquid chromatography (HILIC), and ion chromatography (IC). Moreover, the stationary phase exhibited exceptional retention repeatability in per aqueous liquid chromatography, showcasing its potential as an environmentally friendly analytical method. Mechanistic investigations unveiled multiple solute-stationary phase interactions, including π-π interactions, hydrogen bonding, and ion exchange. Finally, we applied the developed stationary phase for the precise detection of preservatives in carbonated beverages and jelly, achieving high levels of accuracy and recovery rates.
研究领域:
分析化学
·
环境科学
·
食品科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MACROMOLECULES
·
2025
·
IF 5.2
Mengru Ding,Lingling Ni,Ying Zheng,Bao Wang,Chengtao Yu,Guorong Shan,Yongzhong Bao,Junfeng Liu,Pengju Pan
Long-spaced aliphatic polyesters are typical sustainable polyethylene (PE)-like polymers. However, the presence of a low amount of ester groups can exert a profound effect on the crystalline structure of such PE-like polymers. Herein, we synthesized a series of long-spaced aliphatic polyesters bearing two proximate ester groups from ethylene glycol (EG) and n-methylene diacids (n = 9–18) and investigated their polymorphic crystallization and phase transitions. We find that the EG-based polyesters exhibit unique crystal polymorphism and phase transition behaviors. They can form a metastable hexagonal phase (form II) with nontilted, extended chain conformations at low temperatures or during rapid cooling but adopt the thermally stable orthorhombic phase (form I) with tilted chain packing at high temperatures or under slow cooling. Form I demonstrates a more densely packed chain structure and displays distinct mechanical properties compared to form II. The metastable hexagonal phase can transform into an orthorhombic phase during heating through a melt-recrystallization mechanism. This study advances the current understanding of the multiphase crystallization of PE-like long-spaced polyesters.
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 19
·6465
·
IF 4.927
He Chang,Yang Lu,Yantao Sun
In this paper, a new aqueous two-phase extraction system(ATPES) consisting of UCON (poly(ethylene glycol-ran-propylene glycol) monobutyl ether)–NaH2PO4was established, and four trace polycyclic aromatic hydrocarbons (PAHs: fluorene, anthracene, pyrene and phenanthrene) in water and soil were analyzed by high-performance liquid chromatography (HPLC)–ultraviolet detection. In the multi-factor experiment, the central composite design (CCD) was used to determine the optimum technological conditions. The final optimal conditions were as follows: the concentration of UCON was 0.45 g·mL−1, the concentration of NaH2PO4was 3.5 mol·L−1, and the temperature was 30 °C. The recovery of the four targets was 98.91–99.84% with a relative standard deviation of 0.3–2.1%. Then UCON recycling and cyclic tests were designed in the experiment, and the results showed that the recovery of PAHs gradually increased in the three extractions because of the remaining PAHs in the salt phase of last extraction. The recovery of PAHs in the UCON recycling test was less than that in the extraction test due to the wastage of UCON. In addition, a two-phase aqueous extraction model was established based on the random forest (RF) model. The results obtained were compared with the experimental data, and the root mean square error (RMSE) was 0.0371–0.0514 and the correlation coefficient R2was 96.20–98.53%, proving that the model is robust and reliable.Keywords:aqueous two-phase separation;high-performance liquid chromatography;polycyclic aromatic hydrocarbons;determination
研究领域:
环境科学
·
分析化学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2018
·
IF 3.716
Yujie Zhang,Qiaoqi Li,Benlin Dai,Shouyong Zhou,Mingliang Zhang,Haifeng Han,Hongdeng Qiu
A new polar-embedded aromatic stationary phase has been prepared by covalently attaching p -biphenylacetamide silane to silica spheres. The retention behavior of this phase was compared with an alkylamide counterpart and octadecyl phases using different classes of analytes, including geometric isomers and congeners from Standard Reference Materials 869b, 870 and 1647e, positional isomers of electron-deficient benzenes, as well as alkylbenzenes and alkylbiphenyls. The relationship between shape selectivity and surface chemistry of stationary phase was comparatively studied. Influences of the embedded group and ligand length and/or size on the chromatographic selectivity towards various congeners were established. The new polar-embedded aromatic phase possessed unique benzenoid affinity, enhanced aromatic selectivity, distinct charge-transfer properties, as well as good water-wettablity, as a result it can be employed in normal phase, reversed-phase and per -aqueous modes.
研究领域:
分析化学
·
色谱技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）