POLYMER DEGRADATION AND STABILITY
·
2020
·
IF 4.032
Zhiyuan Chi,Zongwei Guo,Zice Xu,Mengjie Zhang,Ming Li,Lei Shang,Yuhui Ao
Searching a renewable and flame-retardant alternative to bisphenol A epoxy resins is a necessary development trend. Diphenolic acid , a plant derivative, has been proven to be one of the sustainable alternatives to bisphenol A. However, how to impart the flame-retardant property to diphenolic acid thermosets is still a challenge to synthesize high performance intrinsic flame-retardant bio-based epoxy resins. A flame-retardant bio-based epoxy resin (TEBA) was designed and synthesized via a three-step synthetic pathway from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)、diethanolamine and diphenolic acid (DPA). The chemical structures of the intermediate and final products were confirmed by 1 HNMR and FTIR spectroscopy. TEBA cured with 4,4′-diaminodiphenylmethane (DDM) curing agent was compared with a standard bisphenol A epoxy resin (DGEBA). Due to the combination of phosphorus and nitrogen in the main chain, the TEBA-DDM shows superior flame retardancy. Compared with DGEBA-DDM, LOI of TEBA-DDM increased from 25.8% to 42.3%, UL-94 test rating from no rating to V-0 rating, self-extinguishing within 3s. The peak heat release rate (PHRR) in the cone calorimetry test decreased by 67%. total heat release (THR) and total smoke generation (TSP) decreased by 27% and 35%, respectively. In addition, the flame retardant mechanism of TEBA epoxy thermosets was researched by FTIR, residual char photograph, SEM, TG-IR analysis and Raman spectroscopy . Meanwhile, TEBA-DDM and DGEBA-DDM have comparable mechanical properties .
研究领域:
材料科学
·
化学工程
·
高分子科学
·
可持续化学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2024
·Vol. 14
·期 12
·8204-8213
·
IF 3.9
Fangli Li,Ziqin Huang,Changjiang Liu,Meini Yang,Jixiang Wu,Wenhui Rao,Chuanbai Yu
Currently, additively efficient flame retardants are being developed to enhance the smoke suppression, flame retardancy, and thermal properties of composite materials. To this end, the current study designed and prepared a novel P/N/Si/Zn-containing organic–inorganic hybrid denoted as APHZ. Its inorganic part was 2-methylimidazole zinc salt (ZIF-8), which improved its smoke suppression and catalytic carbonization. The organic part (P/N/Si-containing compound) promoted its flame retardancy and interfacial compatibility between APHZ and epoxy resin (EP). The test results revealed that EP/APHZ-3 composites achieved a V-0 rating and a notable LOI value of 30.7% when introducing 3 wt% APHZ into the EP matrix. Cone calorimetry tests (CCT) further demonstrated that the average heat release rate (av-HRR), total smoke production (TSP), and CO production (COP) of EP/APHZ-3 were reduced by 23.3%, 14.0%, and 21.1%, respectively. Meanwhile, the char residual was increased by 60.6%, as compared to pure EP. Furthermore, the flame-retardant mechanism of EP/APHZ composites was investigated by the XPS, TG-FTIR, and Raman spectroscopy techniques. The observed synergistic effect of the imidazole skeleton ZIF-8 and P/N/Si-containing compound in APHZ facilitated the generation of a dense multi-element char layer, with the condensed phase flame-retardant mechanism playing a dominant role. These findings contribute to developing and designing high-performance flame-retardant EP.
研究领域:
材料科学
·
化学工程
·
高分子科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2018
·
IF 3.956
Qilei Yang,Ang Cao,Na Kang,Kang An,Zhao-Tie Liu,Yuan Liu
The catalyst for direct ethanol synthesis (DES) from syngas was investigated in this work, which is Co/La 2 O 3 -doped La 4 Ga 2 O 9 . The catalyst was prepared by using LaCo 1−x Ga x O 3 with perovskite phase as the precursor to intensify the interaction in the elements of Co, La and Ga. The catalysts were characterized by using XRD , H 2 -TPR, TEM , EDS, XPS , BET, ICP and TG techniques. This catalyst showed high selectivity to ethanol and excellent stability including excellent resistance to sintering and carbon deposition . It seems that the ethanol is generated in the interface between metallic Co and La 4 Ga 2 O 9 , and in the interface cobalt would be positively charged due to the interaction between Co nanoparticles and La 4 Ga 2 O 9 . The results and the related discussions indicate that Co/La 2 O 3 -doped La 4 Ga 2 O 9 catalyst is a promising catalyst for DES from syngas. Graphical abstracts.
研究领域:
催化
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2022
·
IF 10.723
Pengchao Xie,Yan Peng,Liyan Qiu
To explore effective therapeutic strategy on nonalcoholic fatty liver disease (NAFLD), the amphiphilic oligochitosan derivative containing ursodeoxycholic acid (UDCA) was synthesized and named as UBC, which could self-assemble and encapsulate exenatide (Exe) to obtain Exe-UBC nano-vesicle. Exe-UBC could be uptaken by fatty-acid cultured cells and release UDCA and Exe responsive to the high esterase concentration. In vitro experiments demonstrated that Exe-UBC activated the expression level of SIRT1 with inhibited expression of PGC-1β and PPAR-γ and consequently exerted synergistic bioaction immediately on reducing lipidosis. After a month of Exe-UBC treated through intravenous injection, the body weight of high-fat diet feeding C57BL/6 mice recovered to ordinary level, and their lipid contents in the liver declined significantly. The recovery in hepatic function indexes like TG , AST , and ALT further revealed the superiority of Exe-UBC vesicles. These results suggested that the co-delivery of UDCA and Exe via Exe-UBC could be a potent platform for NAFLD treatment.
研究领域:
药学
·
生物技术
·
分子生物学
·
药理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
International Journal of Analytical Chemistry
·
2022
·
IF 1.698
Lijing Li,Kaixuan Zhou,Qiulu Zhao,Yuejie Wang,Jia Liu,Huiwei Bao
Buyang Huanwu Decoction (BHD) has lipid-lowering and antioxidant effects. In this study, HPLC was used to establish the fingerprint of extracts from different polar parts of BHD. Through the L02 cell lipid deposition model induced by oleic acid, extracts from different polar parts of BHD were administered for treatment. Oil red O staining, TG detection, and MDA detection were used to determine lipid deposition and antioxidant activity. The component-effect relationship is established by using grey relational analysis and PLSR analysis. The results showed that the extracts from different polar parts of BHD could reduce the levels of TG and MDA. The grey relational analysis showed that the peaks that contributed greatly to the reduction of TG and MDA were peaks 3, 16, 14, 10, 1, 15, 2, and 11, respectively. Peaks 1, 4, 9, 10, 14, 16, and 17 could reduce TG and MDA through PLSR analysis. According to the results of grey relational analysis and PLSR analysis, peaks 1, 10, 14, and 16 may have good lipid-lowering and antioxidant effects. This study provides a certain preliminary basis for follow-up research on lipid-lowering drugs.
研究领域:
药理学
·
生物化学
·
中医药
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POLYMER SCIENCE
·
2024
·
IF 3.9
Lei Yang,Jinglei Xing,Minghui Bai,Xingzhong Fang,Guofei Chen
Transparent polyimides were expected to be an alternative to glass substrates. To meet the requirements of high transparency, high heat resistance, and low coefficients of thermal expansion (CTE) for substrate materials, a series of poly(amide-imide)s (PAIs) were synthesized from 2,2′-bis(trifluoromethyl)benzidine (TFDB), (hexafluoroisopropylidene)diphthalic anhydride (6FDA), cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA), terephthaloyl chloride (TPC) and 9,9-bis(4-aminophenyl)fluorene (FDA) with different substituents. And the corresponding films were prepared by adding 0 or 2 pph lithium chloride (LiCl). Through the adjustment of monomer ratio, regulation of the amino ortho -position of diamine monomer, and coordination of Li ions, all PAIs exhibited high glass transition temperatures ( T g ) of 390°C–436°C, low CTE of 12.5–60.9 ppm K −1 , excellent optical transmittances of 71%–84% at 400 nm, high tensile strengths of 140–204 MPa, and high tensile moduli of 4.4–7.2 GPa. In particular, PAI-M-1-2-2Li showed the best comprehensive properties with the transmittance of 83% at 400 nm, T g of 432°C, CTE of 18.7 ppm K −1 , tensile modulus of 6.9 GPa and tensile strength of 204 MPa, which made it competitive in flexible display applications. Graphical
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
INDUSTRIAL CROPS AND PRODUCTS
·
2023
·
IF 5.9
Donghua Li,Feng Shi,Meihua Fu,Yi Lu,Can Liu,Xu Lin,Defa Hou,Hao Sun,Cuiping Luo,Zhifeng Zheng,Yunwu Zheng
To unveil the nitrogen migration and conversion characteristics, catalytic copyrolysis of biomass pseudo components and polyamide (PA) with different blend ratios (1:0, 5:1, 3:1, 1:1, 1:3, 1:5, 0:1) under an ammonia atmosphere was proposed to boost the yield of N-containing compounds (NCCs) and N-rich biochar. The evolution and distribution of NCCs in liquid, gas and biochar were systematically investigated with a combination of TG-MS, Py-GC/MS and EPR. Synergistic effects and possible reaction pathways were also evaluated. Experimental results showed that PA could obviously boost biomass conversion due to increasing the chance of secondary cleavage, and the comprehensive synergistic effect of biomass-derived H* radicals, acid sites of the catalyst and cracking reactions (-C-N and C-C bonds) that reduced the reaction energy barrier and enhanced the NH 3 and HCN yields. NH 3 comes from the amino acids that are released from the amino acid pyrolysis and hydrolysis of HCN on the surface of char, while HCN is from the secondary cracking of primary pyrolysis products. Adding biomass increased CO 2 , CO, CH 4 , C-O and C O emissions from co-pyrolysis. Additionally, significant synergetic effects were observed when Biomass/PA= 3:1, which improved the NCCs and pyridine yields by 78.58% and 48.23%, respectively, under the HZSM-5 catalyst. A lower proportion of PA addition facilitated the Maillard reaction and amide bond cleavage to enhance the NCCs content and suppressed π-conjugated ring structure compound evolution and coke-derived O-containing compound polymerization, while a higher content of PA was favorable for amine and diaza heterocycle compound formation. Moreover, the addition of PA reduced the HHV and N content in biochar, resulting in lower pyrrole-N content and graphitization degree due to secondary cross-polymerization reaction of reaction volatiles, but it enhanced the polarity due to higher oxygen content (14.98%).
研究领域:
能源与燃料
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2023
·
IF 6.8
Shaolin Xie,Bing Yang,Siying Li,Liangjun Ge,Min Li,Qingshi Chen,Xian Qing,Jixing Zou
CYP1A is the most commonly used biomarker and transgenic fish which carrying a cyp1a promoter to drive a reporter gene can be used as reliable way to monitor dioxin/dioxin-like compounds (DLCs) in the environment. Here, we cloned the cyp1a promoter of Gambusia affinis and this promoter showed stronger transcriptional activity than that of zebrafish. Then, a Tg(GAcyp1a:eGFP/Luc) transgenic zebrafish line was first constructed with the G. affinis cyp1a promoter driving eGFP expression using meganuclease I-SceI mediated transgenesis technology. The Tg(GAcyp1a:eGFP/Luc) larvae at 72 h post-fertilization (hpf) were tested by exposing to TCDD for 72 h, and induced GFP was mainly expressed in the liver with low background. The Tg(GAcyp1a:eGFP/Luc) zebrafish showed high sensitivity (limit of detection of 0.322 ng/L TCDD and 0.7 TEQ-ng/L PCDD/Fs) and specificity (insensitive to responses to PAHs and PCBs). In addition, the transgenic line showed a low detection concentration of the DLCs contaminated environmental samples (as low as 1.8 TEQ-ng/L), and the eGFP fluorescence intensity and the chemical-TEQ values were closely correlated. In conclusion, a sensitively and specifically transgenic zebrafish line was established to convenient and effective to detect DLCs in the environment.
研究领域:
环境科学
·
分子生物学
·
毒理学
·
遗传学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2019
·
IF 3.78
Tian Liu,Xingrong Zeng,Xuejun Lai,Hongqiang Li,Yanlin Wang
Organosilicon materials with high capacity of organic-to-inorganic conversion at elevated temperature are always favorable in the field of high-temperature-resistant materials, flame retardant materials, chemical engineering and functional materials in electrical engineering. In this work, it was found out that the platinum-nitrogen catalytic system could obviously enhance the organic-to-inorganic conversion efficiency of silicone rubber (SiR) at elevated temperature. The residual rate of Pt/N/SiR (SiR containing 0.33 phr Karstedt's catalyst (Pt) and 2 phr nitrogenous silane (N)) at 1000 °C was significantly improved from 3.0% to 44.8% in comparison with SiR and its thermal stability was also enhanced. DLS , TEM and UV–vis absorption spectrometry revealed that the platinum in Karstedt's catalyst would aggregate at elevated temperature and deteriorate its catalytic activity for organic-to-inorganic conversion of SiR. And the addition of nitrogenous silane can efficiently inhibit the aggregation and retain the high catalytic efficiency of platinum. A thorough TG-FTIR study, together with SEM/EDX and XPS analyses suggested that the platinum-nitrogen system might suppress the intramolecular cyclic transition and enhance the radical coupling between polymer chains of SiR during thermal degradation , which resulted in the high capacity of organic-to-inorganic conversion of Pt/N/SiR at elevated temperature.
研究领域:
材料科学
·
化学工程
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
Food & Function
·
2017
·Vol. 8
·期 9
·3259-3270
·
IF 3.247
Xiaozhou Zhou,Shiguo Chen,Xingqian Ye
The anti-obesity effects of different proanthocyanidin extracts (PE) from Chinese bayberry (Myrica rubra Sieb.et Zucc.) leaves were evaluated in a high-fat (HF) diet-induced obese rat model. The leaves of Chinese bayberry (LCB), a non-desaccharified proanthocyanidin extract (NDPE), and a desaccharified proanthocyanidin extract (DPE) were compared with orlistat, a conventional anti-obesity drug used as a positive control. The rats from all of the PE-treated groups showed obvious weight loss, with the greatest weight loss in the DPE group (P < 0.05). Compared to the HF group, almost all of the PE-treated groups showed significantly reduced levels of serum TC, TG, AST, ALT, ALP, LDL-C, ADP and a LEP/ADP ratio, and increased levels of HDL-C and LEP. Furthermore, the expression levels of SIRT1, PPAR-γ, C/EBP-α, BMP4 and UCP1 were investigated in the liver, kidney, epididymis and abdominal adipose tissue. Compared to the HF group, PPAR-γ and C/EBP-α levels were significantly reduced and SIRT1, BMP4 and UCP1 levels were significantly upregulated in the DPE-treated group. Our results suggested that PE exerted its anti-obesity effects by upregulating the expression of SIRT1, thus inducing the deacetylation of PPAR-γ and downregulating the expression of C/EBP-α, and also upregulating the expression of BMP4 to boost the levels of brown fat.
研究领域:
药理学
·
营养学
·
分子生物学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of CO2 Utilization
·
2020
·
IF 5.993
Guangyong Shi,Wei Xu,Jichao Wang,Ye Yuan,Somboon Chaemchuen,Francis Verpoort
The coordination of pyridylcarboxylate (isonicotinic acid, IN) with copper (II) fabricates a Cu(IN)-MOF. The characteristic properties of the Cu(IN)-MOF are obtained via different analysis techniques such as XRD, SEM, BET, ICP, TG, etc. The advantage of copper(II) coordinated with a bi-functional organic linker (IN), containing a pyridyl and carboxylate group, is demonstrated by the chemical properties of which the Cu(II)-based MOF exhibits excellent catalytic performance for the CO 2 carboxylation of terminal alkynes. No noble-metal, co-catalyst, or additives are required to execute the reaction. The effectiveness of the Cu(IN)-MOF was demonstrated with a variety of substrates (>11). Moreover, the Cu(IN)-MOF, as a heterogeneous catalyst, can be recycled at least 5 times retaining its excellent catalytic performance. Herein, we report the first copper (II) metal-organic framework (Cu(IN)-MOF) applied for the carboxylation of alkynes with CO 2 demonstrating several advantages such as stable catalyst, avoiding the use of an expensive noble-metal, straightforward synthesis.
研究领域:
材料科学
·
催化
·
化学工程
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2023
·
IF 8.4
Shiyao Lu,Jian Zhang,Hao Meng,Xiaoyuan Qin,Jianbin Huang,Yehao Liang,Feng-Shou Xiao
Dehydration of methyl lactate (ML) obtained from biomass is a sustainable route for the production of methyl acrylate (MA). Herein, we demonstrate that cesium-exchanged Al-rich Beta zeolite (Cs-Beta) is highly efficient for the dehydration of ML to MA, exhibiting full ML conversion with 87.4% MA yield at 340 °C. In situ FT-IR spectra and kinetic studies provide evidence that the ML dehydration on the Cs-Beta zeolite follows a forward ion-exchange/dehydration/reverse ion-exchange reaction pathway. Model experiments, DFT calculations, TG-DSC analysis, and FT-IR spectra showed that coke formation competes with the dehydration of ML to MA. Kinetic studies and theoretical simulations demonstrate that cesium cations in the micropores of Beta zeolite have a strong steric hindrance, suppressing the formation of oligomers and coke. These results offer new insights for developing highly selective and stable catalysts for the dehydration of ML to MA in the future.
研究领域:
化学工程
·
催化
·
材料科学
·
可持续化学
✓ 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）