Crystals
·
2017
·Vol. 7
·期 4
·99
·
IF 1.566
Hongqiang Gao,Wenjuan Wei,Liyuan Dong,Guoqiang Feng,Xingxing Jiang,Rong Wu,Zheshuai Lin,Wei Li
The elastic properties of a zeolitic metal-azolate framework, Zn(mtz)2(MAF-7, mtz−= 3-methyl-1,2,4-triazolate), have been examined from the view point of the first principles calculations and experiments. Our results demonstrate that the three independent elastic constants of MAF-7 are about 5.0–73.3% higher than those of ZIF-8, though they are isomorphic. The electron-donating effect of the nitrogen atom at the 2-position in mtz- ring dominantly accounts for such a prominent difference. The detailed analysis of the full elastic tensors reveals that the volume moduli, shear moduli, and Poisson’s ratios of MAF-7 are about 3.4% to 20.1%, 3.2% to 20.6%, and −30.3% to 12.3% higher than those of ZIF-8. The underlying structural reasons were discussed to explain the anisotropic difference of those properties. Moreover, the conclusion deduced from first-principle calculations was also been verified by nanoindentation and high-pressure synchrotron X-ray diffraction measurements.Keywords:zinc-triazolate framework;elastic constants;volume moduli;shear moduli;Poisson’s ratios
研究领域:
材料科学
·
物理化学
·
机械工程
✓ 已验证
DOI
高影响因子
MACROMOLECULES
·
2024
·
IF 5.1
Jian Tang,Haodong Hu,Ralph H. Colby,Quan Chen
Polymer gels are three-dimensional polymer networks immersed in solvents. They usually exhibit tunable elasticity and swellability that both depend on the solvent quality as a function of the temperature. The development of temperature-insensitive gels is essential in some applications such as treating retinal detachments and scaffolds for tissue regeneration, where the volume change caused by swelling and deswelling is undesirable. To this end, it is feasible to tune either the content and species of the polymer or those of the solvent. Nevertheless, the testing of the temperature dependence of swelling is a laborious process because the equilibration of a gel sample of approximately centimeter dimensions at one temperature can take several hours or even days. In this study, we selected a neutral tetrapoly(ethylene glycol) gel (Tetra-PEG gel) in various mixed solvents as a model system to explore the relationship between the overlap concentration of the precursor solution and the elastic shear modulus and the swelling ratio of the gel network. Our findings reveal that rheometric analysis offers an efficient approach to identifying the optimal mixed solvents, i.e., solvents with temperature-independent interactions with the polymer, to prepare gels having temperature-insensitive swellability over a wide temperature range of application.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2023
·
IF 6.6
Huimin Qi,Xuemei Lei,Jianzhen Gu,Yafeng Zhang,Xingshi Gu,Gai Zhao,Jiaxin Yu
Organogels with low modulus are widely used as anti-icing materials due to their low ice adhesion strength . In this work, the poly(dimethylsiloxane) swelled with silicone oil , trimethyl terminated poly(dimethylsiloxane), vinyl terminated polydimethylsiloxanes, and hydride terminated poly(dimethylsiloxane) were prepared, respectively. The organogels with a wide range of shear modulus displayed various ice adhesion strength. In particular, the lowest ice adhesion strength 6.5 kPa was obtained for poly(dimethylsiloxane)/100 trimethyl terminated poly(dimethylsiloxane) at −10 °C. After being placed for 60 days, the ice adhesion strength of poly(dimethylsiloxane)/trimethyl terminated poly(dimethylsiloxane) almost maintained the previous effect. We believed that the low modulus and the lubricated film co-contributed to this result. However, the even lower modulus of poly(dimethylsiloxane) gels enhanced the ice adhesion strength due to the failure within poly(dimethylsiloxane) gels. Molecular dynamics further demonstrated that the ice adhesion strength was almost independent on the electrostatic interactions and van der Waals. This work opens up new opportunities for tailoring modulus of organogels by tuning structures and composition of de-icing materials.
研究领域:
材料科学
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Physics
·
2023
·
IF 11.5
Yadong Yu,Ding Weng,Lei Chen,Jiadao Wang
In this study, the effective large-scale deicing based on the interfacial toughness-tuning strategy of an ultraviolet-curable PDMS coating was developed. Methacrylate groups were grafted on the hydroxyl-terminated PDMS molecular chains to endow PDMS the response to UV irradiation. Then the precursor was doped with different proportions of silicon dioxide nanoparticle (SiO 2 NP) to tune the interfacial toughness between the coating and the ice layer. The PDMS coating was fabricated through manual spraying and the polymerization under UV irradiation. The effects of the amounts of the methacrylate groups and SiO 2 NP on the deicing properties of UV-curable PDMS coatings were investigated systematically. In addition, it was found that the large-scale deicing performance of the PDMS coating with 10% SiO 2 NP improved when lowering the ambient temperature, which was mainly related to the increase of the shear modulus and thermal residual stress on the interface and might indicate attractive advantage on the extremely cold environment. Meanwhile, the durability and the adaptability to different substrates of the PDMS coating were also examined for the verification of the possible practical application. In summary, the effective large-scale deicing based on the interfacial toughness tuning of a UV-curable PDMS coating was achieved and the coating showed great potential for practice.
研究领域:
材料科学
·
化学工程
·
涂层与薄膜
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2025
·
IF 4.3
Wang Xue,Xin Zhang,Chaoying Sun,Chenlong Wei,Liqun Zhang,Hui Yang,Runguo Wang
Pressure-sensitive adhesives (PSAs) are widely used materials, yet most of their raw materials are currently derived from nonrenewable petroleum resources. The PSA industry faces challenges including the depletion of petroleum resources, high solvent emissions, and carbon-intensive manufacturing processes. To address these issues, a series of poly(dibutyl itaconate-co-butyl acrylate-co-acrylic acid-co-glycidyl methacrylate) (PDBAG) copolymers were synthesized via high-temperature semicontinuous emulsion polymerization, using fully biobased dibutyl itaconate (DBI) as a monomer. The structures and properties of PDBAG with varying DBI and glycidyl methacrylate (GMA) contents were systematically characterized. An optimal balance between adhesion and cohesion was achieved at a GMA content of 0.5 wt %. Remarkably, increasing DBI content from 30 wt % to 50 wt % enhances the high-frequency shear loss modulus (G″) from 55.5 to 87.3 kPa (measured at T = 40 °C, ε = 1%) and correspondingly improves the 180° peel strength with SUS from 10.7 N/25 mm to 16.5 N/25 mm. This enhancement mechanism is attributed to increased energy dissipation within the PSA network during peel deformation. They surpass commercial acrylic PSAs in both peel strength and shear holding power. Biobased PSA partially replaces petroleum-based acrylics in the polymer backbone and features simpler, more eco-friendly processing while maintaining outstanding adhesion. This establishes a sustainable pathway for next-generation adhesive development.
研究领域:
高分子科学
·
可持续材料
·
胶粘剂与密封材料
·
绿色化学
·
乳液聚合
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
·
2021
·
IF 4.346
Shengwei Zhang,Bo Peng,Dan Luo
Adsorption loss of surfactants by rock formations reduces surfactant efficiency and increases cost. We propose a new approach to solve this problem. Xanthan gum/locust bean gum (XLB) and xanthan gum/konjac glucomannan (XKG) were chosen as surfactant carriers. Both XLB and XKG are thermosensitive; they are in a gel state at low temperature and sol state at high temperature. When the temperature near an injection well is low, gelled carriers can shield surfactant charge and reduce adsorption loss of surfactants by the formation. A high temperature deep in the reservoir transforms the carriers into a sol state to release the surfactants. In this way, the transport distance of the surfactants is increased, which enables the surfactants to contact more crude oil. The effects of ratio, pH, and salinity on the rheological properties of the XLB and XKG systems were evaluated to optimize the formulation and define the sol–gel transition temperature (T sol/gel ). The storage modulus and loss modulus of the system was affected by the ratio of rigid glue (XG) and flexible glue (LBG and KGM). Adding acid or base weakened the shear modulus, CaCl 2 and NaCl had little effect on the shear modulus, and KCl significantly increased this property. The shear modulus of these two systems was greatest when the two biogels were mixed in equal proportion, the pH was not adjusted, and 3% KCl was added. Environmental scanning electron microscopy images revealed that KCl transformed the loose porous crosslinked structure into a dense lamellar structure. Sodium lauryl sulfate (SDS) and hexadecyl dimethylamine betaine had little influence on the shear modulus of the system, while cetyl trimethyl ammonium bromide prevented the systems from gelatinizing. The zeta potential and surface tension of XLG (XLB with 2% KCl) and XKG (XKG with 2% KCl) with 3% SDS were measured. The absolute values of their zeta potentials in the gel state were smaller than those in the sol state, which indicates that XLG and XKG effectively shielded surfactant charge. The surface tension decreased with increasing temperature. When the temperature was higher than the T sol/gel , the gel melted completely and the surface tension was almost unchanged. This indicates that the surfactants were released slowly by the carriers before melting was complete. Both XLG and XKG proved to be efficient carriers for surfactants that are used for oil displacement.
研究领域:
石油工程
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2023
·
IF 4.6
Xuanyu Shi,Li Yang,Shihao Sun,Jun Zhong,Xiaofeng Yu,Min Zuo,Yihu Song,Qiang Zheng
In natural rubber (NR), the non-rubber components such as protein and phospholipids strongly influence the Payne effect and Mullins effect while the mechanisms are not yet clarified so far. Herein deproteinized NR (DPNR) and transesterified DPNR (TEDPNR) are prepared and rheological behaviors are investigated. It is shown that the non-rubber components greatly retard the terminal flow behavior. In comparison with NR, DPNR and TEDPNR exhibit significant hysteresis and worse recoverability under large amplitude shear. During cyclic tensile deformation, the DPNR vulcanizate behaves similar to the NR one, while the TEDPNR one demonstrates higher deformation energy normalized with theoretical shear modulus and dissipation ratio. It is suggested that both the protein and phospholipids influence the Payne effect of NR gum by forming aggregates and creating intermolecular association. On the other hand, the phospholipids rather than protein strongly influence the Mullins effect by lowering their crosslinking density and associating the rubbery chains. This investigation would be enlightening for understanding the mechanisms of the Payne effect and Mullins effect of the NR materials.
研究领域:
材料科学
·
高分子科学
·
流变学
✓ 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）