CHINESE JOURNAL OF POLYMER SCIENCE
·
2019
·Vol. 37
·期 6
·598-603
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IF 2.804
Xia De-Yong,Jiang Qi-Min,Huang Wen-Yan,Yang Hong-Jun,Xue Xiao-Qiang,Jiang Li,Jiang Bi-Biao
The anionic polymerization of methyl methacrylate (MMA) was carried out using phosphazene base t -BuP 4 and ethyl acetate (EA) as the catalyst and the initiator, respectively. Gas chromatography (GC), size exclusion chromatography (SEC) measurements, and nuclear magnetic resonance (NMR) analyses were used to reveal the polymerization mechanism and to confirm the polymer structure. The results confirmed the proposed polymerization mechanism and the polymer structure, while the initiator efficiency was low. Meanwhile, the initiation by methoxy anion coming from hydrolysis of the ester bond in MMA was also observed. As a result, there is a marked deviation between the theoretical molecular weight and the measured molecular weight, and it is essential to carry out the polymerization at excessive dosage of t -BuP 4 for preparing polymers with narrow molecular weight distribution.
研究领域:
高分子化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF LOSS PREVENTION IN THE PROCESS INDUSTRIES
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2023
·
IF 3.5
Xiaohua Cui,Xuefeng Gui,Jiwen Hu,Ziyang Gong,Renjie Zhou,Daguang He,Shudong Lin,Yonglu Dong,Yuanyuan Tu
The bulk polymerization of methyl methacrylate (MMA) is of great importance in chemical industry, but the polymerization process is highly hazardous, and few reports have focused on the effect of initiators on its thermal hazards. In this work, to thoroughly explore the thermal hazard characteristics, the runaway behavior of MMA bulk polymerization is investigated by a combination of thermodynamics experimental and kinetics theoretical methods. The results indicate that the presence of initiator exhibits an undesirable thermal hazard to the MMA bulk polymerization, and its exothermic behavior is also greatly influenced by the type and concentration of initiator. For azobisisoheptanenitrile (ABVN), azodiisobutyronitrile (AIBN) and dibenzoyl peroxide (BPO) initiators as examples, the AIBN-initiated reaction has the shortest adiabatic induction period (39.51 min), whereas the BPO-initiated polymerization exhibits the strongest maximum temperature-rising rate and maximum pressure-rising rate. Under adiabatic runaway, the temperature and pressure change significantly with increasing AIBN concentration, revealing a great potential risk of thermal runaway. Kinetic parameters are calculated to further understand the thermal runaway mechanisms, showing a strong agreement with the adiabatic experimental data. Finally, based on the cooling failure scenario, severity grading is determined by the evaluation criteria. The current work provides extensive data as a reference and guidance for the process design and optimization of MMA bulk polymerization from the perspective of safety.
研究领域:
化学工程
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安全科学
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产品关联
DOI
高影响因子
Polymers
·
2021
·Vol. 13
·期 22
·3860
·
IF 4.329
Do Quang Tham,Mai Duc Huynh,Nguyen Thi Dieu Linh,Do Thi Cam Van,Do Van Cong,Nguyen Thi Kim Dung,Nguyen Thi Thu Trang,Pham Van Lam,Thai Hoang,Tran Dai Lam
In this study, vinyltrimethoxysilane-treated hydroxyapatite (vHAP) and PMMA-grafted HAP (gHAP) were successfully prepared from original HAP (oHAP). Three kinds of HAP (oHAP, vHAP and g HAP) were used as additives for the preparation of three groups of HAP-modified PMMA bone cements (oHAP-BC, vHAP-BC and gHAP-BC). The setting, bending and compression properties of the bone cements were conducted according to ISO 5833:2002. The obtained results showed that the maximum temperature while curing the HAP-modified bone cements (HAP-BCs) decreased from 64.9 to 60.8 °C and the setting time increased from 8.1 to 14.0 min, respectively, with increasing HAP loading from 0 to 15 wt.%. The vHAP-BC and gHAP-BC groups exhibited higher mechanical properties than the required values in ISO 5833. Electron microscopy images showed that the vHAP and gHAP nanoparticles were dispersed better in the polymerized PMMA matrix than the oHAP nanoparticles. FTIR analysis indicated the polar interaction between the PO4groups of the HAP nanoparticles and the ester groups of the polymerized PMMA matrix. Thermal gravimetric analysis indicated that mixtures of ZrO2/HAPs were not able to significantly improve the thermal stability of the HAP-BCs. DSC diagrams showed that the incorporation of gHAP to PMMA bone cement with loadings lower than 10 wt.% can increase Tgby about 2.4 °C.Keywords:HAP-modified bone cement;vinyltrimethoxysilane-treated HAP;PMMA-grafted HAP;bending;ISO 5833
研究领域:
生物材料学
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骨科医学
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产品关联
DOI
PubMed
高影响因子
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
·
2023
·Vol. 30
·期 5
·2142-2149
·
IF 3.1
Wenjia Zhang,Shixun Hu,Yaru Zhang,Qi Zhang,Mingti Wang,Juan Li,Xinhua Dong,Xiyu Zhang,Shangshi Huang,Wei Wang,Qi Li,Jinliang He
Polypropylene (PP) is regarded as an environmentally friendly cable insulation material to replace cross-linked polyethylene (XLPE) owing to its thermoplastic nature, high-temperature resistance, and outstanding dielectric characteristics. Grafting modification was applied to satisfy the demand for a higher voltage power grid, and it was proved to be effective in enhancing the insulating performance of PP. The electrical tree is a common cause for cable insulation failure. This study examines the electrical tree initiation and growth characteristics of methyl methacrylate (MMA)-grafted PP under different temperatures. Our results indicate that high temperature can promote the electrical treeing process while grafting modification can hinder the process. The trap characteristics show that more deep traps are introduced in the grafted materials that can limit the motion of electrons and, thus, restrict the electrical tree initiation process. The crystallization morphology shows that the size of spherulites increases and the boundaries of the spherulites become blurry with higher MMA content. The compressed amorphous region and the tortuous boundaries of the crystalline can hinder the electrical treeing process. High temperature may improve charge carrier mobility and enhance the molecular chain relaxation, thus enlarging the free volume and finally accelerating the treeing process. The findings of this study would serve as a reference for designing grafted PP insulation for power cables.
研究领域:
材料科学
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电气工程
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产品关联
DOI
高影响因子
POLYMER SCIENCE SERIES B
·
2023
·Vol. 65
·期 2
·103-110
·
IF 1.2
Tianchen Song,Xiang Yixin,Gao Jiangang,Shen Xianrong
Abstract In this paper, ethyl lactate was used as a green solvent for iron(III)-catalyzed activators generated by electron transfer atom transfer radical polymerizations of methyl methacrylate in the absence of any external ligand. The effects of amount and type of solvent were investigated. Most of the systems showed the typical features of reversible deactivation radical polymerization. The polymerization of methyl methacrylate with ethyl lactate as a solvent and a ligand proceeded in a controlled manner as demonstrated by the first-order kinetic plot, low dispersity of polymers, an increase in polymer molecular weight with rise of the monomer conversion and by chain extension experiments.
研究领域:
材料科学
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聚合物化学
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DOI
高影响因子
FOOD CHEMISTRY
·
2018
·
IF 4.946
Nataliya A. Gavrilenko,Tatyana N. Volgina,Evgeniy V. Pugachev,Mikhail A. Gavrilenko
Polymethylmethacrylate matrix has been developed as an analytical device for visual and spectrophotometric determination of malachite green. Based on the studied effects of different pH levels, temperature, contact time and diverse ions, optimum analysis conditions have been established. For malachite green, the calibration graph was linear in the range of 0.5–30 mg·L −1 in the samples with the detection limit of 1 mg·kg −1 . The proposed simple method makes it possible to determine malachite green visually in the concentration range 8–30 mg·L −1 using a colour scale. The method has been implemented for determination of malachite green in various sea fish samples.
研究领域:
分析化学
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环境科学
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产品关联
DOI
PubMed
高影响因子
CATALYSIS LETTERS
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2018
·Vol. 149
·期 2
·373-389
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IF 2.911
He Teng,Qu Yixin,Wang Jidong
The catalytic performance of cesium oxide supported on three types of silica gel A-type (A-silica), B-type (B-silica) and C-type (C-silica) was tested for the aldol condensation of methyl acetate (Ma) and formaldehyde (FA) to methyl acrylate (MA). The catalysts were characterized using TEM, BET, XRD, FTIR, TG, XPS, and CO 2 -TPD and the reaction mechanisms were explored using DFT calculations. To obtain high selectivity of MA, appropriate amount of Cs loading is required since much higher loading of Cs leads to excessive decomposition of Ma and/or MA. On the Cs/silica, the Si–O–Cs species generated from the reaction of cesium oxide with silanol groups are the active sites as demonstrated by characterization and the DFT calculations. Silica gels with larger pore size and pore volume are preferred since these facilitate the contact of the reactants with active sites and provide higher capacity for accommodation of coke. As compared with Cs/SBA-15, Cs/B-silica seems more prospective for industrial application due to the lower cost of silica gel and even better performance. Graphical Abstract
研究领域:
催化化学
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理论计算化学
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产品关联
DOI
高影响因子
Materials
·
2017
·Vol. 10
·期 11
·1239
·
IF 2.654
Bing Yu,Liang He,Yifan Wang,Hailin Cong
Magnetic porous microspheres are widely used in modern wastewater treatment technology due to their simple and quick dye adsorption and separation functions. In this article, we prepared porous polymethylmethacrylate (PMMA) microspheres by the seed-swelling method, followed by in situ formation of iron oxide (Fe3O4) nanoparticles within the pore. Then, we used diazo-resin (DR) to encapsulate the porous magnetic microspheres and achieve PMMA@Fe3O4@DR magnetic material. We studied the different properties of magnetic microspheres by different dye adsorption experiments before and after the encapsulation and demonstrated that the PMMA@Fe3O4@DR microspheres can be successfully used as a reusable absorbent for fast and easy removal of anionic and aromatic dyes from wastewater and can maintain excellent magnetic and adsorption properties in harsh environments.Keywords:poly (methylmethacrylate) (PMMA);magnetic;diazo-resin (DR);adsorption;dye
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Materials
·
2018
·Vol. 11
·期 5
·705
·
IF 2.467
Bing Yu,Tingting Xue,Long Pang,Xiulan Zhang,Youqing Shen,Hailin Cong
Monodisperse cross-linked porous poly (methyl methacrylate) (PMMA) microspheres (~2.5 μm in diameter) were prepared by using an improved two-step seed swelling polymerization method with monodisperse micron-grade PMMA microspheres seeds. The porous PMMA microspheres with diverse surface morphology and pore structure were obtained by tuning porogen systems. The monodisperse porous PMMA microspheres, which were prepared using toluene:dibutylphthalate (DBP) = 1:1 (v/v) as a porogen system, had the smallest pore size and the largest specific surface area. Then, the monodisperse porous PMMA microspheres were subjected to high-performance liquid chromatography. The liquid chromatographic column filler successfully realized complete separation of arginine, glycine and glutamic acid, and the separation effect was good. The porous PMMA microspheres provide a new material for the separation of amino acids by liquid chromatography.Keywords:poly (methyl methacrylate), seed swelling polymerization;porous microspheres;high-performance liquid chromatography
研究领域:
材料科学
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分析化学
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产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2018
·
IF 3.909
Manli Yang,Liang Wang,Yanzhi Xia
The graft copolymerization of methyl methacrylate (MMA) onto alginate was carried out in aqueous media by initiators of ammonium persulphate under a nitrogen gas atmosphere. Then, the grafting of PMMA chains onto the alginate backbone was confirmed through the study of Fourier transform infrared, X-ray diffraction, scanning electron microscopy and 1 H nuclear magnetic resonance spectroscopy . At last, a thin and transparent polymethyl methacrylate grafted alginate film with high strength was obtained by the casting method. The effect of MMA/SA ratio or percentage of graft (G%) on mechanical properties, thermal stability (thermogravimetric analysis/differential thermogravimetry analyses), color, opacity and water resistance of composite films were characterized. Results showed the homogeneous transparent films could be obtained while G% was lower than 8.64%. After being grafted by PMMA, the tensile strength of the films was distinctly improved by 205.3%, as well the elongation at break (E%) by 41.7% while the MMA/SA (g/g) is 0.3. On the other hand, water resistance, thermal stability and crystallinity of the films were improved, however, the transparency was slightly decreased.
研究领域:
材料科学
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食品科学
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产品关联
DOI
PubMed
高影响因子
Arabian Journal of Chemistry
·
2019
·
IF 3.298
Umair Azhar,Rimsha Yaqub,Huateng Li,Ghulam Abbas,Yongkang Wang,Jian Chen,Chuanyong Zong,Anhou Xu,Zhang Yabin,Shuxiang Zhang,Bing Geng
Due to intermediate hydrophobicity of methyl methacrylate (MMA) monomer in water, it is difficult to prepare its stable water in oil high internal phase emulsion (HIPE). Moreover, the addition of fully hydrophilic co-monomer such as 2-hydroxyethyl methacrylate (HEMA) in MMA monomer makes it further troublesome to stabilize these emulsions. This paper addresses the preparation of such type of difficult to prepare emulsions via addition of an amphiphilic fluorinated di-block copolymer (FDB), poly(2-dimethylamino)ethylmethacrylate- b -poly(trifluoroethyl methacrylate) (PDMAEMA- b -PTFEMA) as stabilizer. Interestingly, HEMA and/or HFBA (hexa fluorobutyl acrylate) as co-monomers were successfully added to impart some special properties such as thermodynamic stability, desired amphiphilicity to the final polyHIPEs. Fluorinated blocks in FDB anchored well at oil/water interface of HIPE, offering enough hydrophobicity to the comparatively hydrophilic monomers and in turn providing resistance against coalescence. MMA polyHIPEs were found to be fully hydrophobic just by replacing HEMA co-monomer with HFBA. Due to superb inherent hydrophobic nature of fluorine atoms , MMA-HFBA polyHIPEs showed remarkable water contact angle of 139°. Furthermore, the addition of fluorinated co-monomer in MMA based HIPEs significantly improved thermal stabilities of these materials with improvement in degradation temperature from 305 °C to 360 °C.
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
SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2010
·
IF 3.858
Sude Ma,Guolin Song,Wei Li,Pengfei Fan,Guoyi Tang
Microencapsulated phase change material (MEPCM), paraffin, with polymethylmethacrylate shell was prepared by introducing UV irradiation to an O/W emulsion polymerization for approximately 30 min under constant stirring. The results of differential scanning calorimetry analyses indicate that the latent heat and the content of paraffin of microcapsules are 101 J g −1 and 61.2 wt%, respectively. The phase transition temperature of MEPCM ranges from 24 to 33 °C. The MEPCM was characterized using scanning electron microscopy and Fourier transform infrared spectroscopy. Thermal gravimetric analysis results show that the MEPCM is degraded into two distinguishable steps. Accelerated thermal cycling tests also indicate that the MEPCM displays a good thermal reliability. Gypsum boards composed of as-prepared MEPCM show a good temperature-regulated property. Based on all these results, it can be concluded that the microencapsulated paraffin as MEPCMs have good potential for thermal energy storage purposes such as phase change material slurries, solar space heating applications, textiles and building materials .
研究领域:
材料科学
·
能源存储
·
建筑技术
✓ 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）