BIOMACROMOLECULES
·
2018
·
IF 5.738
Chao Xing,Zhekun Shi,Jiliang Tian,Jing Sun,Zhibo Li
Stimuli-responsive polymers have received increasing interest for a variety of applications. Here, we report a series of unique charge-determined thermoresponsive polypeptoids synthesized by a combination of ring-opening polymerization and click chemistry. The LCST-type and UCST-type behavior is mainly dominated by the charge state on the side chain. Further, the phase transition temperature highly depends on the degree of polymerization, the side-chain architecture, the pH value, and so on. The obtained polypeptoid solutions exhibit good stability against temperature and salt concentration. To our knowledge, this report presents the first charge-determined LCST/UCST-type polymer from identical homopolymer backbone that displays a wide range of tunable cloudy points in aqueous media. We propose the hydrogen-bonding interaction plays a critical part on the solution behavior. These features make polypeptoids ideal candidates for highly designable stimuli-responsive polymeric materials.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2022
·
IF 6.267
Funian Han,Liang Yu,Guanghua Wen,Jun Guo,Chunhua Ran,Shaopeng Gu
In this study, the effect of Na 2 O on the sintering and melting behavior of representative CaO-SiO 2 -CaF 2 slag were synthetically investigated by TG-DSC, DIL, XRD, SEM, XPS, and BET. As expected, most shrinkage of CaO-SiO 2 -CaF 2 slags with and without Na 2 O during the sintering process originated from solid-phase sintering, and the formation temperature of cuspidine as the sintering phase was reduced by Na 2 O to 550 °C. While Na 2 O also transformed Ca 4 Si 2 O 7 F 2 to Ca 2 NaSiO 4 F at 650 °C–880 °C and caused unexpected volume expansion, owing to increased cell volume and corresponding pore expansion. Moreover, Na 2 O reduced the melting point of CaO-SiO 2 -CaF 2 slag and promoted the volatilization of fluoride by changing the final phase before melting.
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
CHINESE JOURNAL OF POLYMER SCIENCE
·
2025
·
IF 4
Zhang Li,Li Xin-Rui,Xiao Xia-Hui,Zhou Li-Dan,Zhu Yu-Wei,Chen Jia-Yu,Jiang Hang,Han Jie,Liu Wei,Ngai To
In this study, a pair of dicarboxylic acids as cis-trans isomerism—citraconic acid (CA) and mesaconic acid (MA), was incorporated into polymeric networks of poly( N -isopropylacrylamide) (PNIPAM)-based core-shell microgels via semi-batch precipitation polymerization. We demonstrated that the pH-temperature dual responsiveness of the core-shell microgels is highly correlated with the structure and position of the acid isomers. Both the cis-trans molecular structure and the crosslinking position of the dicarboxylic acids significantly influenced the hydration capacity and surface charge density of the core-shell microgels. These diverse properties first influenced the swelling behavior, further affecting the interfacial behavior of the microgels, including the oil-water dynamic interfacial tension and air-water compression isotherms. Furthermore, the rheological behavior of the microgel suspensions also displayed distinct dependences on the frequency and temperature, illustrating that the cis-trans molecular structure and crosslinked position of the dicarboxylic acids also significantly influenced the interparticle clustering in the bulk solution. Our results suggest that the pH sensitivity of the cis-trans dicarboxylic acid isomer affects the ionization and surface charge distribution of the core or shell layers of individual microgels, which further determines the interparticle interaction and cooperative rearrangement at interfaces and in the bulk.
研究领域:
材料科学
·
化学工程
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2024
·
IF 12.2
Xiao-qing Li,Zu-lin Hua,Jian-yun Zhang,Jun-liang Jin
Short-chained perfluoroalkyl acids (PFAAs, C n F 2n+1 –R, n ≤ 6) have merged as global concerns due to their extensive application and considerable toxicity. However, long-chained PFAAs (n ≥ 7) featured with high persistence are still ubiquitously observed in aquatic environment . To understand the uptake behavior of short-chained PFAAs in aquatic macrophytes , the uptake kinetics, bioconcentration , and translocation of short-chained PFAAs (3 ≤n ≤ 6) in two typical free-floating macrophytes ( Eichhornia crassipes and Ceratophyllum demersum ) were investigated in the treatments with and without long-chained PFAAs (7 ≤n ≤ 11). Results showed that short-chained PFAAs can be readily accumulated in both E. crassipes and C. demersum , and the uptake of short-chained PFAAs fit the two-compartment kinetic model well ( p < 0.05). In the treatments with long-chained PFAAs, significant concentration decreases of all concerned short-chained PFAAs in E. crassipes and PFAAs with n ≤ 5 in C. demersum were observed. Long-chained PFAAs could hinder the uptake rates, bioconcentration factors , and translocation factors of most short-chained PFAAs in free-floating macrophytes ( p < 0.01). Significant correlations between bioconcentration factors and perfluoroalkyl chain length were only observed when long-chained PFAAs were considered ( p < 0.01). Our results underlined that the effects of long-chained PFAAs should be taken into consideration in understanding the uptake and bioaccumulation behaviors of short-chained PFAAs.
研究领域:
环境科学
·
生态学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Kaihui Ma,Junyi Deng,Qinghui Wu,Peng Hu,Shuxing Qiu,Mao Chen,Jian Xu
Using clean energy in the ironmaking industry is expected to reduce the negative impacts on our environment. H 2 , one of the most important clean energies, has a great potential to partially replace CO in the blast furnace process, thus cutting down CO 2 emission. In order to unravel the distinct effects on the shrinkage behaviour between CO and H 2 , four binary- FeO-rich oxides and four ternary- FeO-rich oxides were employed to compare their performance under the simulated blast furnace cohesive zone conditions. The results show that the formed olivine and solid solution have the intention to dominate the shrinkage of packed bed below 900 °C, while the formed spinel compounds with higher melting point determine the shrinkage above 1300 °C. In comparison to CO, H 2 has a faster gaseous reduction rate. Therefore, the higher quantity of reduced iron and less disintegration of coke in the packed bed simultaneously suppresses the shrinkage between 900 °C and 1000 °C. Besides, the much slower iron carbonization rate in H 2 postpones the re-accelerating of shrinkage as a result of melting and dripping to higher temperatures.
研究领域:
冶金学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Polymer Crystallization
·
2020
·Vol. 3
·期 5
·e10158
·
IF 0
Xiang Li,Xiaolei Dong,Jiale Zhou,Jianna Bao,Shichang Chen,Wangyang Lu,Xianming Zhang,Wenxing Chen
The end group modification of hydrogen bonding units has a significant effect on physical properties of covalent linked polymers. In this study, telechelic poly(ethylene glycol)s (PEG) with various molecular weights were functionalized by thymine (Thy), which was able to form self-complementary double hydrogen bonding. The physical properties of Thy-functionalized PEGs, including viscosity in solution or melt state, crystallization behavior, crystalline structure as well as lamellar structure were systemically investigated by comparison with hydroxyl-terminated PEGs. Crystallinity and melting temperature of linked PEG chains were decreased by the presence of Thy groups and the depression effects were strengthened by increase of Thy content. Crystallization rate and temperatures at which crystallization occurred were more complicated. Lower crystallization rate was obtained for Thy-functionalized PEGs with highest Thy content, a signature for confined crystallization by covalent links to Thy groups. However, in the case of moderate Thy content, the trend of crystallization rate was shifted to lower temperature regions, where the maximum and minimum of crystallization rates were comparable with free polymer chains. For Thy-functionalized PEGs with low Thy content, crystallization rates were similar with that of non-functionalized PEGs. The differences in supercoolings might give explanation on differences in crystallization behaviors among three conditions.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
Journal of Chemistry
·
2012
·
IF 0
Xiao Yan,Hai-Rong Pei,Tong-Bo Wang,Wen-Bo Liu,Xiao-Zheng Lan
Phase behavior of undecane-dodecane mixtures (n-C11H24-C12H26, C11-C12) in bulk and confined in SBA-15 (pore diameters 3.8, 7.8, and 17.2 nm) has been studied by differential scanning calorimetry. Phase diagram of the confined C11-C12 system shows dependence on pore size, indicating simple behavior compared with the bulk. In the three systems, melting points of the confined C11, C12 and the mixtures ( = 0.1–0.9) present a linear relation with the pore diameter from 3.8 to 17.2 nm. Melting behavior of the confined C11-C12 mixtures is closely as the confined C11, C12. Melting temperatures of the three systems have been fitted as a function of mole fraction .
研究领域:
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2023
·
IF 8.7
Haijian Xie,Jiawei Wu,Mengzhen Yu,Huaxiang Yan,Shakil Masum,Peifu Cai,Yun Chen
Bisphenol A (BPA) is a toxic endocrine disruptor often found in landfill leachate . Adsorption behaviors and mechanisms of BPA onto organo-bentonites amended loess , e.g., Hexadecyltrimethylammonium chloride-bentonite (HTMAC-B) and Carboxymethylcellulose-bentonite (CMC-B) were experimentally investigated. The adsorption capacity of loess amended by HTMAC-B (LHB) and CMC-B (LCB) is 4.2 and 4 times greater than that of loess (L), respectively. It is attributed to the increase of hydrogen bonds and hydrophobic lateral interactions between the adsorbent and the adsorbate. The binary (Pb 2+ -BPA) systems may enhance BPA adsorption onto the samples by the formation of coordination bonds between the hydroxyl group of BPA and Pb 2+ ions. A cycled column test was used for investigating the transport behavior of BPA in LHB and LCB samples. The hydraulic conductivity of loess amended by the organo-bentonite (e.g., HTMAC-B, CMC-B) is generally lower than 1 × 10 −9 m/s. Especially for CMC-B amended loess, the hydraulic conductivity can be reduced to 1 × 10 −12 m/s. This guarantees the hydraulic performance of the liner system. Transport behavior of BPA in cycled column test is explained by the mobile-immobile model (MIM). Modelling results showed that loess amended by organo-bentonites can increase the breakthrough time of BPA. In comparison to loess-based liner, the breakthrough time of BPA for LHB and LCB can be increased by a factor of 10.4 and 7.5, respectively. These results indicate that organo-bentonites can serve as a potentially effective amendment for improving the adsorption of loess-based liners.
研究领域:
环境科学
·
土壤学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
DIAMOND AND RELATED MATERIALS
·
2024
·
IF 4.3
Junxin Chen,Ying Long,Hua-Tay Lin,Fenglin Zhang
In present work, FeCoCrNiB 0.15 high-entropy alloy (HEA) with its diamond composite were prepared by spark plasma sintering (SPS) technique at 950 °C. FeCoCrNiMo 0.15 and its diamond composite samples were prepared for comparison. The phase composition and microstructures of FeCoCrNiMo 0.15 and FeCoCrNiB 0.15 HEAs and diamond composite samples were investigated, and the friction and wear behaviors of the HEAs and diamond composites against Si 3 N 4 balls under dry sliding condition in ambient air were compared on a ball-on-disk tester. The results showed that, Cr-rich phase precipitated from the metastable FCC matrix was observed in both HEAs. The relative density of the FeCoCrNiMo 0.15 and FeCoCrNiB 0.15 alloy samples was ∼93.1 % and ∼ 98.4 %, respectively, while the Vickers hardness of the samples was 309.7 ± 10.6 HV 1 and 317.5 ± 8.4 HV 1 , respectively. The wear resistance of FeCoCrNiB 0.15 was higher than that of FeCoCrNiMo 0.15 alloy, and the grinding rate of FeCoCrNiB 0.15 /diamond composite against Si 3 N 4 was higher than that of the FeCoCrNiMo 0.15 /diamond composite. With detailed microstructural analyses, the possible friction and wear mechanism were discussed. Present study shows that the boron-doped HEA matrix in diamond composites is a promising candidate for fabricating diamond tools with long service life and high processing efficiency.
研究领域:
材料科学
·
机械工程
✓ 已验证
DOI
高影响因子
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2017
·
IF 1.591
Yang Wang,Xu-guang Wang
The instability of emulsion explosive matrices is mainly due to the crystallization of interphases as oversaturated aqueous solutions of nitrate salts. The principal features of crystallization for this type of emulsion have been previously studied; however, there is no consensus regarding the mechanism of crystallization for an emulsion explosive matrix. This study is devoted to the investigation of the crystallization behavior of interphase droplets. By monitoring the mass change of emulsions during their aging process, it was found that the mass of the emulsions remains almost constant and that water still completely existed in the emulsion system after crystallization of the interphase droplets. The ammonium nitrate (NH4NO3) crystals in the emulsion explosive matrices were then separated successfully using a simple method. The thermal behavior of pure NH4NO3 and crystals in the emulsion explosive matrices was studied by differential scanning calorimetry-thermogravimetric analysis (DSC-TG) at a heating rate of 10 K/min. The experimental results show that the thermal behavior of the crystals in the emulsions was exactly the same as for pure NH4NO3, meaning that only NH4NO3 crystallized from the emulsion explosive matrices with no water crystals. Thus, it could be concluded that after crystallization of the dispersed drops in the emulsion explosive matrices, pure NH4NO3 crystals and new smaller droplets were produced.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Polymer Chemistry
·
2017
·Vol. 8
·期 37
·5749-5760
·
IF 5.375
Hongcan Zhang,Jian Zhang,Wenxue Dai,Youliang Zhao
The simple and straightforward construction of multi-responsive systems with tunable LCST and UCST dual phase transitions is a great challenge. This study affords an efficient route to tune cloud points via control over the chemical composition of hydroxyl and diethylamino bearing poly(amido thioether)s which were prepared by one-pot thiol–amine–acrylate polyaddition. Owing to the balance of inter/intrachain interactions, various copolymers could exhibit LCST (fOH < 0.84), LCST–UCST (fOH = 0.84–0.89) and UCST (fOH > 0.89) behaviors relying on the hydroxyl fraction in comonomer units. Meanwhile, the thermoresponsive behaviors of copolymer solutions could be efficiently tuned via switching the solvent and solution pH, applying CO2/N2 bubbling, and oxidation. The success of this study further paves the way for the robust synthesis and practical applications of smart polymers with double thermoresponsivity.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2022
·Vol. 20
·期 3
·1636-1645
·
IF 2.328
Yehong Cheng,Fan Zhang,Denghao Ma,Yixin Zhang,Yaxiong Liu,Yumin An,Anzhe Wang,Ning Hu,Libin Zhao,Wenbo Han
Although C f /ZrB 2 –SiC composites prepared via direct ink writing combined with low-temperature hot-pressing were shown to exhibit high relative density, high preparation efficiency, and excellent flexural strength and fracture toughness in our previous work, their oxidation and ablation resistance at high and ultrahigh temperatures had not been investigated. In this work, the oxidation and ablation resistance of C f /ZrB 2 –SiC composites were evaluated via static oxidation at high temperature (1500°C) and oxyacetylene ablation at ultrahigh temperatures (2080 and 2270°C), respectively. The thickness of the oxide layer of the C f /ZrB 2 –SiC composites is <40 μm after oxidizing at 1500°C for 1 h. The C f /ZrB 2 –SiC composites exhibit non-ablative properties after oxyacetylene ablation at 2080 and 2270°C for >600 s, with mass ablation rates of 3.77 × 10 −3 and 5.53 × 10 −3 mg/(cm 2 s), and linear ablation rates of −4.5 × 10 −4 and −5.8 × 10 −4 mm/s, respectively. Upon an increase in the ablation temperature from 2080 to 2270°C, the thickness of the total oxide layer increases from 360 to 570 μm, and the carbon fibers remain intact in the unaffected region. Moreover, the oxidation and ablation process of C f /ZrB 2 –SiC at various temperatures was analyzed and discussed.
研究领域:
材料科学
·
航空航天工程
✓ 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）