Polymers
·
2020
·Vol. 12
·期 9
·1926
·
IF 3.426
Yanyi Wen,Bing Yu,Zhongjie Zhu,Zhuoran Yang,Wei Shao
In the present study, sponges with the antibiotic tetracycline hydrochloride (TCH) loaded into alginate incorporated with gelatin (G/SA) were fabricated. The G/SA sponges were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric (TG) analysis. G/SA sponges show a three-dimensional network structure with high porosity. An excellent swelling behavior and a controlled TCH release performance are observed from G/SA sponges. Moreover, they exhibit good antibacterial activity against both Gram-positive and Gram-negative bacteria.Keywords:alginate;gelatin;porosity;antibacterial
研究领域:
生物材料
·
医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·
IF 7.139
Meigeng Gao,Elena Yu Konysheva,Jun Yang
The La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF) ceramics with the porosity of 20% (LSCF-20) and 50% (LSCF-50) were fabricated through temperature variation. Kinetics of the Cr-adsorption has been studied at 700 °C over 345 h under air. Different dominant mechanisms of Cr chemisorption over the ceramics with different porosities were identified. The Cr–substitution into the LSCF perovskite grains will dominate in the denser LSCF-20 ceramics, whereas the growth of SrCrO 4 crystals over the LSCF perovskite phase will occur preferably in the more porous LSCF-50 ceramics. The Cr penetrates into a more porous LSCF-50 ceramics up to 12–17 μm and the total Cr amount adsorbed after 345 h over the LSCF-50 ceramics is larger by about 10 times than over the denser LSCF-20 ceramics. The revealed remarkable differences could be associated with the increase in the surface area and with a higher volume of macro- and mesoporosity.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2018
·Vol. 102
·期 3
·1414-1424
·
IF 2.956
Yaowu Wei,Tao Zhang,Qi Zhang,Bingqiang Han,Nan Li
Improving the hydration resistance of CaO aggregates is the key to successful application of lime-based refractories in metallurgical industry. Additive Zr(OH) 4 and Al(OH) 3 were introduced in the preparation of CaO granules using granulation equipment and calcination method in this study. The results showed that the hydration resistance of CaO granules was improved significantly, especially for granules with 0.6 wt.% Zr(OH) 4 and 0.9 wt.% Al(OH) 3 , respectively. The shell of CaO granules was relatively dense after calcination and the volume of open pores of CaO granules decreased from 3.56 × 10 −2 to 1.80 × 10 −2 cm 3 /g when additive was introduced. Zr(OH) 4 and Al(OH) 3 have the opposite effect on the closed porosity of CaO granules, the closed porosity of CaO granules was decreased with Zr(OH) 4 addition, but increased with Al(OH) 3 addition.
研究领域:
材料科学
·
冶金工程
✓ 已验证
产品关联
DOI
高影响因子
DESALINATION
·
2015
·
IF 3.756
Lei Wang,Danxi Huang,Xudong Wang,Xiaorong Meng,Yongtao Lv,Xin Wang,Rui Miao
To obtain a high-performance polyvinylidene fluoride (PVDF) membrane, low-temperature thermally induced phase separation (LT-TIPS) was employed to prepare microporous flat PVDF membranes and hollow-fiber membranes using diluent mixtures of triethylphosphate and diethylene glycol monoethyl ether acetate. The membrane morphology was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results show that thermally induced phase separation (TIPS) played a more important role than nonsolvent-induced phase separation (NIPS) in determining the cross-sectional morphology of the membranes, and the surface structure was mainly affected by NIPS in a low-temperature (0 °C) coagulation bath . By increasing the temperature of the coagulation bath, different structures of membranes, such as spherulites and cellular and sponge structures, were observed. It is believed that the formation mechanism of these membranes depended on a combined NIPS and TIPS process. Wide-angle X-ray diffraction (XRD) analysis indicated that PVDF crystallized into an α-phase crystal structure for all the membranes tested. In addition, the porosity, tensile strength and filtration performance of the flat membranes were measured. On the basis of the above results, a hollow fiber membrane with highly interconnected pores and high porosity could be prepared employing LT-TIPS.
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
APPLIED CLAY SCIENCE
·
2018
·
IF 3.641
Shun Wang,Peixin Du,Peng Yuan,Xuemin Zhong,Yaqi Liu,Dong Liu,Liangliang Deng
This work investigated changes in the chemical composition, structure and porosity of hollow spherical allophane under alkaline conditions, which are significant not only for understanding its fate in natural environment but also for its functional applications. Hollow spherical allophane with a silicon/aluminium (Si/Al) molar ratio of 0.77 was hydrothermally synthesised followed by treatment with dilute sodium hydroxide (NaOH) solutions with different concentrations (indicated by pH values). The allophane and its alkali-treated products were then characterized using a combination of techniques, such as Fourier-transform infrared spectroscopy, nuclear magnetic resonance and nitrogen physisorption analysis. Allophane showed a weak structural stability in alkaline conditions. At pH ≤ 11.0, the framework of allophane particles was almost intact; its polymerised silicates showed only slight dissolution. At a higher pH (> 11.0), desilication and dealumination enhanced, resulting in the destruction of the imogolite local structure (ImoLS) along the edges of defect pores and the formation of amorphous materials . Most of the defect pores increased in size, becoming accessible to nitrogen and the textural parameters of the micropores reached their maximum values at a pH of 12.5. However, the damage to some secondary pores and the collapse of some hollow spherules reduced total pore volume ( V total ). At a pH of 13.0, most of the hollow spherules were observed to have collapsed, resulting in remarkable decrease in the textural parameters. However, some unbroken and/or mildly broken allophane particles might remain, deduced from the relatively high BET specific surface area (SSA) and V total and the considerable proportion of micropores for Allo 13.0 . These results reveal the dissolution behaviour of allophane in alkaline conditions and the mechanism underlying this behaviour, providing essential insights into the mineral's potential applications.
研究领域:
土壤科学
·
矿物学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2019
·
IF 3.372
Peng Liu,Mengmeng Chen,Yiqiang Ma,Chuan Hu,Qiugen Zhang,Aimei Zhu,Qinglin Liu
Pervaporation is a promising membrane technology for separation of aqueous organic solution particularly azeotrope and close-boiling point compounds. However, most of pervaporation membranes are based on hydrophilic polymers that suffer decline of separation performance due to their swelling in aqueous solution. Here we present a copolymer synthetic strategy for preparation of hydrophobic polymer pervaporation membrane with hierarchical porosity via uniting both rigid and flexible segments. The synthesized membrane has well-defined micropores and high free volume faction of 8.03% with cavity size of 0.476 nm, and demonstrate exceptional performance with high permeability and selectivity for dehydration of alcohols. In the pervaporation of ethanol-water azeotrope, the membrane displays the high permeabtion flux of 74.6 μm kg m −2 h −1 and water selectivity of 34 (separation factor of 732) at 30 °C. The developed strategy has excellent potential for synthesizing copolymers for high-efficient pervaporation membranes.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MICROENCAPSULATION
·
2019
·
IF 2.04
Zhaoying Wu,Mengqing Zhao,Wei Zhang,Zhao Yang,Shuxin Xu,Qing Shang
The purpose of this study was to investigate the influences of drying methods on the risperidone (RIS) release profiles of RIS-loaded PLGA microspheres. These microspheres were fabricated with an O/W emulsion solvent evaporation method. The wet microspheres were dried with freeze drying and vacuum drying methods. The microspheres were mono-dispersed spheres with an average diameter of 100 μm. Studies found that drying methods had great influence on the porosity, morphology, and release profiles of RIS-loaded PLGA microspheres. Specifically, the freeze-dried microspheres had higher porosity (78.46 ± 1.64%) than those vacuum-dried ones (52.45 ± 2.68%), and they showed higher RIS release rates (p < 0.05). In the accelerated release tests (45 °C), these microspheres dried under the pressures of 700 mmHg and 200 mmHg gave faster release rates than those ones dried under the pressure of 450 mmHg. Importantly, the accelerated release test (45 °C) had a high correlation with the real-time test (37 °C) (R2 > 0.99). These studies exhibited a significance in the precise preparation of RIS-loaded PLGA microspheres.
研究领域:
药学
·
生物材料学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Materials Today Nano
·
2021
·
IF 8.109
C. Zeng,K. Wang,L. Pan,B. Li,J. Li,L. Zhou,W. Zhang,C. Liang,H. Pan
Green synthesis of nanocarbons from greenhouse gas CO 2 has been achieved by introducing lithium hydride into CO 2 system. However, the role of lithium hydride in determining the morphology and microstructure of nanocarbons is not revealed. Herein, the morphology and porosity of nanocarbons are found to be related to particle sizes of LiH. Gas blowing velocities of H 2 and CO 2 , increased with the decreasing particle size of LiH, and their distribution are revealed to the most important factors for the morphology and porosity of nanocarbons. The understanding of the roles of lithium hydride in green synthesis of nanocarbons may shed light on the design and large-scale synthesis of nanomaterials with desired morphology and microstructure.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2023
·Vol. 16
·期 19
·6612
·
IF 3.4
Bo Li,Lei Fan,Jie Bai,Jinhang He,Jianfeng Su,Song Wang,Chao Deng,Shifeng Liu,Zhiqing Zhang
Porosity is closely related to the corrosion and wear properties of a coating processed by thermal-spraying technology, and the quantitative characterization of porosity is a crucial part of the research on coating structures. The current image analysis method often uses the mechanical polishing method recommended by ISO to measure a coating porosity. This method has been proved to be an effective method for the characterization of oxide coatings. However, due to the significant differences in the physical and chemical properties between aluminum and oxides, this method may not be suitable for aluminum coatings, and a more appropriate approach needs to be explored. In this paper, the effects of three polishing technologies (mechanical polishing, argon-ion-beam polishing, and electrolytic polishing) on the porosity measurement of pure aluminum coatings were compared and studied. The research results showed that the commonly used mechanical polishing method and more advanced argon-ion-beam polishing method could not completely reveal the pore structure because SiC particles would be embedded in the pure aluminum coatings during mechanical polishing, filling large pores. Although electrolytic polishing technology had advantages in revealing the macroporous structure, it would introduce a microporous structure and oxides, which would affect the measurement of the coating porosity. The composite polishing technology (electrolytic polishing + argon-ion-beam polishing) could perfectly reveal the pore structure in the pure-aluminum coating, and the porosity of arc-sprayed aluminum coating was 9.9%, which was close to the macroscopic true value measured using the weighing method of 10.2%.Keywords:coating;mechanical polishing;argon ion beam;electrolytic polishing;porosity
研究领域:
材料科学
·
表面工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Qianjie Niu,Jiwei Jiang,Changsong Zhan,Yujie Tao,Zijun Ye,Jian Huang,Bin Dong,Zhenhui Kang
With the world's population expanding rapidly, modern agriculture is evolving at a swift pace, leading to a significant increase in food production, primarily through the use of chemical fertilizers. However, this heavy reliance on fertilizers has led to issues such as soil compaction and decrease of earthworm abundance. Herein this study reports a smart soil consisting of conventional soil and carbon dots (CDot) based smart material which is capable of automatically adjusting its porosity and soil aggregate size. Due to the responsiveness, The CDot-based smart soil can lift its height up to 150% upon humidity stimulation due to the increased porosity which is similar to the effect caused by earthworms. Based on this effect, this smart soil can increase the growth rate of maize seedlings by 40%, thus showing great potentials in agriculture.
研究领域:
农业科学
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2020
·
IF 5.289
Zhijun Wang,Baoqiang Xu,Jia Yang,Bin Yang,Heng Xiong,Guobo Yang,Fengkang Wang
A route is present for preparing porous titanium scaffolds with open and interconnected pore morphology through calcium thermal in-situ reduction of TiO precursor. Titanium and dioxide titanium powders, with ammonium carbonate as the space holder, were used to prepare porous precursor whose main phase is TiO by a sintering process. Then calcium vapor was conduced to reduce the precursor and CaO was removed by leaching to obtain porous titanium structures. The morphology, pore structure, phase analysis of porous titanium precursor and porous titanium scaffolds were investigated by means of XRD, SEM and EDS. The porosity was observed by Archimedes method. By this route, the porous titanium with multi-gradient pore sizes ranging from a few microns to several hundred microns was formed. The porous titanium is of multi-gradient pore size distribution of 100 μm bigger, 10 μm∼100 μm and 10 μm smaller. The micro-pores on the pore walls increases connectivity between the macro-pores throughout the porous titanium interior. The porous titanium obtained by this method has a porosity of 50–65% and a titanium content more than 99%.
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
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Jiaojun Tan,Yanwei Luo,Meiyun Zhang,Bin Yang,Fangfang Li,Shaowei Ruan
Aramid paper has been widely used in high-voltage motors and transformers due to its excellent insulation property and thermal durability. However, the smoothness and chemical inertness of aramid fibers lead to a loose structure (voids) of aramid paper, which limits its potential applications in harsh environments, such as high-frequency and high-voltage circuits. This work reports a simple and efficient method to improve the mechanical and insulation properties of meta-aramid paper via controllable dissolving and regeneration of aramid fibers. To obtain a dense and robust structure, the pristine meta-aramid paper was immersed in a dimethyl sulfoxide/potassium hydroxide (DMSO/KOH) mixture to make aramid fibers swelled and dissolved, followed by regeneration in water vapor, eventually generating densified aramid paper with fewer voids and enhanced insulation and mechanical performance. Optimum conditions resulted in aramid paper with the best comprehensive performance, and the tensile strength, Young’s modulus, and electrical breakdown strength of the consolidated aramid paper were 22.85 MPa, 0.72 GPa, and 15.3 kV/mm, respectively, which were significantly higher than those of the pristine aramid paper (12.53 MPa, 0.41 GPa, and 8.36 kV/mm). Meanwhile, such treatment did not cause any chemical structure change, and thus it still retained the excellent thermal resistance (Td > 430 °C) of aramid fibers. This simple method can effectively regulate the surface porosity and the mechanical and breakdown strength of aramid paper, as well as provide a generic method for postprocessing and enhancing aramid paper.
研究领域:
材料科学
·
电气工程
✓ 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）