JOURNAL OF CHEMICAL THERMODYNAMICS
·
2019
·
IF 2.29
Ying Zhang,Junshuai Chen,Taotao Zhan,Xiangyang Liu,Maogang He
Ethyl myristate is one of the main components of biodiesels and its thermophysical properties are critical to be supplemented and perfected. In this work, the speed of sound and thermal diffusivity of ethyl myristate were measured by the light scattering method. The investigated temperature and pressure is ranged from 303.15 K to 560.15 K and up to 10 MPa. The relative expanded uncertainties of the speed of sound and thermal diffusivity were estimated to be less than 1.3% and 2.6% (k = 2), respectively. The correlations for the speed of sound and thermal diffusivity as function of temperature and pressure were presented based on the experimental data. The absolute average deviations (AADs) between the experimental data and the calculated results are 0.04% for the speed of sound at atmospheric pressure, 0.07% for the speed of sound at p > 0.1 MPa and 0.28% for the thermal diffusivity , respectively.
研究领域:
化学工程
·
能源科学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2022
·
IF 8.025
Wenjian Huang,Xin Wen,Jin Zhou,Xuzhen Zhang
Poly (L-lactic acid) (PLLA) based copolymers modified with δ -valerolactone (DVL) through random copolymerization (PVLA-R) and block copolymerization (PVLA-B) with various DVL content were prepared to investigate their degradation regulation and mechanism. Chemical structure , thermal properties , hydrophilicity , crystallization as well as the crystal defects of the obtained copolymers were respectively confirmed. Degradation regulation of both PVLA-R and PVLA-B, such molecular weight and pH value changes of PLLA based copolymers were investigated via vitro degradation method. In order to further explore the degradation principle of the two copolymers , their degradation residues at different stages were systematically studied. The addition and increasing content of DVL disturbs the regularity of original PLLA molecular structure, resulting in accelerating degradation of copolymers . Compared with amorphous region, the crystalline region of both two copolymers has better corrosion resistance , which could be confirmed by increased melting point and crystallinity of both PVLA-R and PVLA-B degradation residues. PVLA-B copolymers show relatively superior degradation resistance mainly due to their higher molecular weight , crystallinity and hydrophobic index than PVLA-R copolymers.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
DOI
高影响因子
SYNTHETIC COMMUNICATIONS
·
2020
·
IF 1.796
Xiaoyun Ma,Zhiyuan Liang,Xiuhai Gan,Gang Wei,Qingdi Zhou
Obtucarbamate A was purified from Disporum cantoniense with good antitussive property. In present work, a series of obtucarbamate A derivatives were designed and synthesized from obtucarbamate A by microwave method, and their antitussive activity were evaluated. The results showed that the toluene diisocyanate was obtained with a yield of 95.1% using a simple method, 1-methyl-2-pyrrolidinone as solvent, temperature of 190 °C, microwave irradiation at 60 W power for 30 min. All compounds have good antitussive activity, and small steric hindrance unsaturated groups of ester chains and amino groups favor activity. It is the first reported of obtucarbamate A derivatives used as antitussive, and the results provide a basis for the application of obtucarbamate derivatives as new antitussive.
研究领域:
药理学
·
有机合成化学
✓ 已验证
DOI
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2014
·Vol. 113
·期 1
·211-223
·
IF 0.983
Wang Chenwei,Gui Xia,Yun Zhi
A new activated carbon catalyst (AC) with relatively high density of –SO 3 H group was synthesized by HNO 3 oxidation followed by sulfonation with H 2 SO 4 . After 10 wt% HNO 3 oxidation for 8 h and subsequent sulfonation for 15 h, the total acid density and the density of the –SO 3 H group in AC were determined by titration to be 4.43 mmol/g and 0.93 mmol/g, respectively. The resulting AC exhibited relatively high catalytic performance for the esterification of lauric and oleic acid in methanol, which was due to an obvious increasing of –SO 3 H group density. In the meantime, the catalytic performance correlated with density of total acidity and esterification rates was also revealed.
研究领域:
化学工程
·
催化材料
✓ 已验证
DOI
高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2020
·Vol. 20
·期 12
·7376-7384
·
IF 1.134
Yuan Chen,Ren Xin,Ye Huilin,Jin Shue,Zuo Yi,Li Jidong,Li Yubao
Mechanical and degradation properties are crucial factors of guided tissue/bone regeneration (GTR/GBR) membranes. In this work, a series of fibrous membranes with different ratios of polycaprolactone (PCL) and gelatin (Gel) were prepared (PCL:Gel = 1:9 (P1G9), 3:7 (P3G7), 5:5 (P5G5),
7:3 (P7G3), and 9:1 (P9G1)) by electrospinning, and their physicochemical properties and In Vitro degradation behaviors were systematically investigated. Mechanical tests showed that tensile strength was enhanced with the presence of Gel, and the tensile strength of the P9G1 membrane
reached nearly three times that of the pure PCL membrane. The degradation rate of the composite membranes could be adjusted by controlling the ratio of PCL and Gel; the higher the Gel content was, the faster the degradation of the PCL/Gel membrane. The higher PCL content favored maintaining
the fibrous structure of the electrospun membranes. These findings will be beneficial for designing PCL/Gel composite materials for biomedical applications.
研究领域:
生物材料学
·
组织工程学
✓ 已验证
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Xiaosheng Du,Jinghong Qiu,Sha Deng,Zongliang Du,Xu Cheng,Haibo Wang
Organic phase change materials (PCMs) have attracted increasing attention in the solar energy utilization field for their large thermal energy storage density, appropriate phase transition temperature, and excellent chemical stability. However, the liquid leakage defect and poor solar-thermal conversion performance restrict their large-scale application. Herein, novel PCM composites with superior solar-thermal conversion efficiency, excellent form-stability, and improved thermal conductivity were successfully synthesized by introducing a dopamine-decorated MXene (Ti3C2Tx@PDA) into a poly(ethylene glycol) (PEG)-based polyurethane PCM. Ti3C2Tx@PDA, which was covalently bound to polyurethane, acted as a photon capturer and molecular heater and converted solar energy to thermal energy, whereas the PEG-based polyurethane PCM could absorb and store the generated thermal energy through solid–solid phase transition. Sunlight irradiation experiments demonstrated that the solar-thermal conversion and storage efficiency of PCM composites (up to 90.1%) were significantly improved with the introduction of the MXene Ti3C2Tx@PDA. Based on differential scanning calorimetry (DSC) analysis, PCM composites exhibited satisfactory phase change enthalpy in the range of 121.9–128.2 J/g. Moreover, the developed PCM composites possessed excellent form-stability, remarkable thermal reversibility, good thermal stability, and improved thermal conductivity. In conclusion, the synthesized PCM composites exhibited tremendous application potential in solar energy utilization field.
研究领域:
材料科学
·
能源工程
✓ 已验证
DOI
高影响因子
ACS Omega
·
2020
·
IF 2.87
Maoyong Zhi,Quanyi Liu,Yinlong Zhao,Shansong Gao,Zheng Zhang,Yuanhua He
A novel MoS2–DOPO hybrid has been successfully synthesized through the grafting of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) on the surface of MoS2 nanosheets using allyl mercaptan as an intermediate. MoS2–DOPO was used as a flame retardant additive to prepare flame-retardant flexible polyurethane foam (FPUF). The influence of MoS2–DOPO on the mechanical, thermal stability, and flame retardancy properties of FPUF composites were systematically investigated. The incorporation of MoS2–DOPO could not deteriorate greatly the tensile strength and 50% compression set of FPUF composites, but effectively improves the char residue. The cone calorimeter and smoke density tests results revealed that the peak heat release rate, total heat release, and the maximum smoke density of the MoS2–DOPO/FPUF composite were reduced by 41.3, 27.7, and 40.5%, respectively, compared with those of pure FPUF. Furthermore, the char residue after cone calorimeter tests and pyrolysis gaseous products of the MoS2–DOPO/FPUF composite were analyzed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and thermogravimetric analysis/infrared spectrometry. The results suggested that the MoS2–DOPO hybrid played a synergistic flame retardant effect of gas and condensed bi-phase action. In addition, a possible flame retardancy and smoke suppression mechanism of the MoS2–DOPO/FPUF composite were proposed. This study provides a facile and promising strategy for the fabrication of polymer materials with excellent flame retardancy and smoke suppression properties.
研究领域:
材料科学
·
高分子化学
·
燃烧学
✓ 已验证
DOI
PubMed
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2014
·
IF 2.633
Jun-Bo Zhang,Xiu-Li Wang,Qiu-Xia He,Hai-Bo Zhao,Yu-Zhong Wang
Poly(1,4-cyclohexylenedimethylene terephthalate) (PCT) is a commercialized semicrystalline high-temperature thermoplastic polyester, but its flammability restricted its applications in some fields. A third monomer , 2-(6-oxido-6H-dibenz < c,e > <1,2> oxaphosphorin-6-yl)-1,4-hydroxyethoxy phenylene (DOPO-HQ-HE), was used to synthesize an intrinsic flame-retardant copolyester through trans-esterification and polycondensation . Its chemical structure was confirmed by 1 H NMR and ICP-AES. The crystallization behavior of PCTDs was investigated by DSC and WAXD , and found that the introduction of DOPO-HQ-HE slightly reduced the crystallization ability of PCT. TGA results showed that the incorporation of phosphorus-containing monomer improved the thermal stability of copolyesters both in nitrogen and air. Flynn–Wall–Ozawa method was used to analyze the thermal degradation kinetics of copolyesters, and found that the apparent activation energy was enhanced. The microscale combustion calorimetry (MCC) showed that PCTDs had lower heat release rate and total heat release than PCT. The results of the limiting oxygen index (LOI), the UL-94 vertical and the cone calorimeter test indicated that DOPO-HQ-HE endowed PCTDs with flame-retardant properties to some extent. Besides this, the cone calorimeter results show that the introduction of DOPO-HQ-HE remarkably suppressed the smoke release of PCT. The pyrolysis behaviors of PCT and PCTDs were investigated by Py-GC-MS, and found that the decomposition of PCT chains usually happened at ester bond and followed the random chain scission mechanism. The introduction of DOPO-HQ-HE almost had no effect on the thermal degradation mechanism of PCT.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Materials Science & Engineering C-Materials for Biological Applications
·
2017
·
IF 4.164
Yayuan Guan,Yuling Su,Lili Zhao,Fancui Meng,Quanxin Wang,Yongchao Yao,Jianbin Luo
Polyurethane micelles with disulfide linkage located at the interface of hydrophilic shell and hydrophobic core (PU-SS-I) have been shown enhanced drug release profiles. However, the payloads could not be released completely. The occurrence of aggregation of hydrophobic cores upon shedding hydrophilic PEG coronas was considered as the reason for the incomplete release. To verify the above hypothesis and to develop a new polyurethane based micelles with dual stimuli respond properties and controllable location of pH and reduction responsive groups in the PU main chains, a tertiary amine was incorporated into the hydrophobic core PU-SS-I, which resulted polyurethane with both reduction and pH sensitive properties (PU-SS-N). Biodegradable polyurethane with only disulfide linkages located between the hydrophilic PEG segment and the hydrophobic PCL segments (PU-SS-I) and polyurethane with only pH sensitive tertiary amine at the hydrophobic core (PU-N-C) were used as comparisons. Paclitaxel (PTX) was chosen as mode hydrophobic drug to evaluate the loading and redox triggered release profiles of the PU micelles. It was demonstrated that PU-SS-N micelles disassembled instantly at the presence of 10 mM GSH and at an acidic environment (pH = 5.5), which resulted the nearly complete release (~ 90%) of the payloads within 48 h, while about ~ 70% PTX was released from PU-SS-I and PU-SS-N micelles at neutral environment (pH = 7.4) with the presence of 10 mM GSH. The rapid and complete redox and pH stimuli release properties of the PU-SS-N nanocarrier will be a promising anticancer drug delivery system to ensure sufficient drug concentration to kill the cancer cells and to prevent the emergency of MDR. The in vitro cytotoxicity and cell uptake of the PTX-loaded micelles was also assessed in H460 and HepG2 cells.
研究领域:
材料科学
·
药学
·
肿瘤学
✓ 已验证
DOI
PubMed
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2020
·
IF 4.469
Xiaoqian Ji,Jingyan Liu,Wan Zhang,Wenwen Liu,Chaoxia Wang
Various molecular thermochromic blocked waterborne polyurethanes have been synthesized via incorporating rhodamine B derivative (RhEA). The effect of molecular weight on the thermal properties, rheological behaviors, and thermochromic properties of the thermochromic polyurethanes were tested. The molecular weight of the thermochromic polyurethanes were tailored in the range of 3317–20,377 by choosing polyethylene glycol (PEG200/600/1000) with various molecular weight as soft segments. The results showed that the thermal decomposition temperature of thermochromic polyurethane with the higher molecular weight was higher. The absorbance of thermochromic polyurethanes gradually increased with the increase of induction time. Additionally, the absorbance of PU-PEG200 was lowest because it had least repetition unit. The thermochromic behaviors of polyurethanes were not affected by the molecular weights. The application performances of synthesized thermochromic polyurethanes in textile printing as a functional colorant were also measured. It was found that the actual lines width of PU-PEG200 were less than the theoretical value and the rate of change was negative. This phenomenon was due to the poor water solubility. The K/S of the printed fabrics with polyurethanes gradually raised with the increase of UV induction time. The thermochromic behaviors of fabrics were also not affected by the molecular weights.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Yunliang Jiang,Yumin Dong,Yong Xiong,Jun Li,Jianping Zhou,Hongbo Liang,Binghua Zhou,Bing Xie
To meet the non-removable application scenarios of most integrated electronics, the development of polymer-based packaging materials possessing superior thermal conductivity and self-healing characteristics simultaneously is necessary. However, on account of the complexity of composite structure and composition , its self-heal remains a formidable challenge. Herein, we have designed a self-healing and thermally conductive bi-functional polyurethane composites with Diels-Alder structure (PUDA) and silver nanowires (AgNWs). The hydrogen-bonding network at the interface of AgNWs and PUDA facilitated the dispersion of AgNWs in the matrix, which endows the composites with desirable thermal conductivity . Incorporating 3, 6, 9, 12, and 15 wt% of AgNWs into PUDA leads to increases in thermal conductivity of 33%, 104%, 154%, 321%, and 371%, respectively. In particular, the novel composites incorporated 12 wt% AgNWs exhibited the most efficient balance between self-healing efficiency and thermal conductivity performance. The thermal conductivity of PUDA/AgNWs with 12% of AgNWs content is 1.01 W/mK, which is 4.8 times that of PUDA (0.21 W/mK). After two reconstitution cycles, the thermal conductivity of PUDA/AgNWs-12 was restored to 85%. This study demonstrates the successful preparation of composites possessing both desirable thermal conductivity and self-healing capabilities, rendering them suitable for use as thermal interface materials in thermal management systems and flexible electronics applications.
研究领域:
材料科学
·
纳米技术
·
热管理
✓ 已验证
DOI
高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2022
·
IF 9.463
Mei Wan,Congling Shi,Xiaodong Qian,Yueping Qin,Jingyun Jing,Honglei Che,Fei Ren,Jian Li,Bin Yu
In this study, three-dimensional flower-like Ni-MOFs were fabricated and successfully functionalized on multi-terminal lamellar MXene (Ti 3 C 2 T x ) by solvothermal method, and their flame retardant application in thermoplastic polyurethanes (TPU) was investigated. As expected, the addition of Ni-MOF@Ti 3 C 2 T x can improve the flame retardancy and smoke suppression properties of TPU. The heat release rate, the smoke release rate, total smoke production, CO and CO 2 release of the composite with only 1 wt% MOF@Ti 3 C 2 T x were significantly reduced by 15%, 44%, 26%, 18%, and 8%, respectively. Furthermore, the carbon residues of TPU/Ni-MOF@Ti 3 C 2 T x composites were about 2–5 times that of pure TPU, indicating that the Ni-MOF@Ti 3 C 2 T x can inhibit the thermal degradation of TPU. The mechanism illustrated that the excellent fire safety properties of TPU/Ni-MOF@Ti 3 C 2 T x composites are due to the physical barrier, catalytical carbonization, and gas-phase flame retardant of Ni-MOF@Ti 3 C 2 T x . In this work, the dispersity, thermal stability, and flame retardancy of MXene were improved due to the modification of MXene with Ni-MOF by chemical bonding and physical adsorption, which can broaden the range of applications of MOFs .
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）