Polymers
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2022
·Vol. 14
·期 15
·3158
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IF 4.967
Chunxia Zhu,Shuyu Pang,Zhaoxia Chen,Lehua Bi,Shuangfei Wang,Chen Liang,Chengrong Qin
At present, the synthesis methods of crystalline porous materials often involve powder products, which not only affects the practical application but also has complex synthesis operations and limited scale. Based on the mechanochemical method, we choose COF-TpPa-1, preparing TpPa-1-DANC composites. Covalent organic frameworks (COFs) are a kind of crystalline material formed by covalent bonds of light elements. COFs possess well pore structure and high thermal stability. However, the state of synthesized powders limits their application. Cellulose nanocrystals (CNCs) are promising renewable micron materials with abundant hydroxyl groups on their surface. It is possible to prepare high-strength materials such as film, water, and aerogel. Firstly, the nanocellulose was oxidized by the sodium periodate method to obtain aldehyde cellulose nanocrystals (DANC). TpPa-1-DANC not only had the crystal characteristic peak of COFs at 2θ ≈ 5° but also had a BET surface area of 247 m2/g. The chemical bonds between COFs and DANC formed by Schiff base reaction appeared in FTIR and XPS. The pyrolysis behavior of the composite was characterized by TG-IR, which showed that the composite had good thermal stability. With the advantages of nanocellulose as a material in every dimension, we believe that this method can be conducive to the large-scale synthesis of COFs composites, and has the possibility of multi-form synthesis of COFs.Keywords:covalent organic frameworks;aldehyde cellulose nanocrystals;mechanochemistry;TGA/FTIR
研究领域:
材料科学
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化学工程
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分析化学
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DOI
PubMed
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2020
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IF 3.905
Mudassir Hussain Tahir,Xingxing Cheng,Rana Muhammad Irfan,Rizwan Ashraf,Yiteng Zhang
The present study proposed successfully TG-FTIR as a novel technique for high quality bio oil production having desirable concentration of targeted products especially phenols and acids. TG-FTIR analysis of pine waste was performed to calculate yield of desirable chemical compounds at different temperature ranged 350−600 °C. While, bio oil was produced at each corresponded temperatures and GC–MS analysis was carried out to support TG-FTIR analysis which showed high consistency. Additionally, efficient extraction of phenolic compounds was performed via complex method using Ca 2+ as a complex agent under alkaline conditions which showed that 95 % phenols were extracted successfully. Meanwhile, production of calcium acetate in residue bio oil turns this study highly valuable for future scientific research.
研究领域:
生物质能
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分析化学
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环境科学
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DOI
高影响因子
BIOMASS & BIOENERGY
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2022
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IF 5.774
Beier Jiang,Yuanyuan Ma,Lijing Wang,Zhou Guo,Xinyu Zhong,Tongtong Wu,Yuanyuan Liu,Haigang Wu
Molecular structure of hyperbranched polyglycerols (hbPGs) strongly affected the thermal stability as the critical heat transfer medium to maintain thermal homeostasis during working of heat engine. Here, thermogravimetric analysis (TGA)-fourier-transform infrared spectroscopy (FTIR)-gas chromatography (GC)-mass spectroscopy (MS) and reactive force-field (ReaxFF) techniques were utilized to identify major thermal decomposition products and explore the molecular mechanism. TGA-FTIR-GC/MS results showed that the major products were CO, CO 2 , water molecules and C3 organic moieties. To perform ReaxFF molecular dynamic simulation, timestep-dependent images revealed that C3 molecules were mainly originated from glycerol units and hydroxyl groups played an essential role in catalyzing thermal decomposition. To examine our hypothesis, different methoxylation levels of hbPGs were prepared, and TGA analysis of these methoxylated hbPGs polymers clearly corroborated that lower percentage of hydroxyl groups in the hbPGs can significantly increase maximum peak temperature from ∼400 °C to ∼460 °C. Our investigation clearly provided the molecular mechanism of hbPGs thermal decomposition and identified a potential way to improve thermal stability of hbPGs.
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高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
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2022
·Vol. 147
·期 23
·13253-13259
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IF 4.755
Chen Yiyang,Wu Weihong,Zhang Man,Cui Yumeng,Zhang Kailun,Qu Hongqiang
The thermal degradation and flame retardancy effect between ionic liquid-modified graphene and hexaphenoxy cyclotriphosphazene on epoxy resin (EP) was investigated using thermogravimetric analysis, differential thermogravimetric analysis, thermogravimetric analysis-infrared spectrometry (TGA-FTIR) and the char residue analysis. The carbonization and synergistic flame-retardant mechanism were obtained. The results showed that, compared with pure EP, the char residue amount of flame-retardant EP was increased, which was dense and continuous with fewer and smaller pores. This was due to the compatibilization of the ionic liquid to the matrix, resulting in the good dispersion of the flame retardant in EP matrix to promote the carbonization efficiency. The TGA-FTIR analysis showed that the PO·and HF free radicals produced by decomposition of flame retardants quenched the flame in the gas phase, and the produced water vapor and NH 3 diluted the concentrations of combustible gas and oxygen to inhibit the progress of combustion. Graphical abstract
研究领域:
材料科学
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燃烧学
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化学工程
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DOI
高影响因子
ENVIRONMENTAL POLLUTION
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2020
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IF 6.793
Yi Liu,Ruojia Li,Jianping Yu,Fengli Ni,Yingfei Sheng,Austin Scircle,James V. Cizdziel,Ying Zhou
Microplastics are ubiquitous in the marine environment but characterizing them in marine organisms is challenging. Herein we describe a method to detect, identify, and quantify microplastics in marine mussels ( Mytilus edulis ) using thermal gravimetric analysis – Fourier Transform infrared spectroscopy – gas chromatography mass spectrometry (TGA-FTIR-GC/MS) after extracting and isolating the microplastics using chemical digestion, density separation, and filtration. Combining the three instrumental techniques adds discriminatory power as temperature profiles, chromatograms, and vibrational and mass spectra differ among common plastics. First, we tested several digestion schemes after spiking the mussels with plastics commonly found in the marine environment, including polyethylene (PE), polystyrene (PS), polypropylene (PP) and polyvinyl chloride (PVC). KOH (10%, w/v) was the most suitable reagent, providing good recoveries (>97%) without degrading the microplastics. We show that the technique TGA-FTIR-GC/MS can be optimized to readily determine both the type (polymer) and amount (mass) of microplastics in the sample. Applied to 100 mussels from each of six locations along the coast of China, we found an average of 0.58 mg of plastic per kg of tissue (range 0.16–1.71 mg/kg), with PE being the most abundant type of plastic measured. Among the coastal cities, mussels from Dalian had the highest microplastic content. Overall, we demonstrate that the method is a powerful technique to quantify masses of microplastics in marine mussels, a species commonly used as a bioindicator of pollution, and may be applied to other biota as well.
研究领域:
环境科学
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海洋生物学
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DOI
PubMed
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2023
·
IF 5.9
Zheng Li,Zuodong Qin,Chunxuan Li,Guimei Zhang,Aozheng Zhang,Sisi Li,Guoqi Liang,Xin Wang,Wufei Tang
Nano calcium carbonate (CaCO 3 ) was successfully treated by tetrabutyl titanate sol together with nickel hydroxide, followed by calcination to form a new kind of flame retardant (Ni-TiO 2 @CaCO 3 ). After study of the Ni-TiO 2 @CaCO 3 structure, it was then introduced into epoxy resin (EP) to improve the flame retardancy and thermal stability. The results shown that NiO and TiO 2 were supported on the surface of the CaCO 3 , and 5 wt% CaCO 3 could enhance the flame retardancy and Ni-TiO 2 @CaCO 3 further increased the flame retardancy of the EP composites. In the cone calorimeter test (CCT), the values of the peak heat release rate (pHRR) and smoke production rate (pSPR) were reduced to 769 kW/m 2 and 0.32 m 2 /s by CaCO 3 from 1101 kW/m 2 and 0.39 m 2 /s of the raw EP respectively. Moreover, pHRR and pSPR values were further decreased to 511 kW/m 2 and 0.25 m 2 /s by Ni-TiO 2 @CaCO 3 respectively. Although the degradation temperature values were lower than that of the control EP, the temperature values at 5 and 50% mass loss for Ni-TiO 2 @CaCO 3 /EP composites were improved compared to the EP. In addition, the char residues value of the Ni-TiO 2 @CaCO 3 / EP composite (23.5%) was obviously improved compared to that of the EP (13.0%) and CaCO 3 / EP composite (16.4%). In addition, the flame retardancy mechanism of the Ni-TiO 2 @CaCO 3 / EP composite was thoroughly analyzed by TGA-FTIR, FITR and Raman methods. This work provides a promising evaluation strategy for utilizing CaCO 3 and its derivatives for possible treatment of EP to enhance its flame retardancy and thermal stability.
研究领域:
材料科学
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高分子科学
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消防安全工程
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DOI
高影响因子
危险品化学品经营许可证（带存储）