Journal of Materials Chemistry A
·
2018
·Vol. 6
·期 36
·17519-17529
·
IF 9.931
Xiaosheng Du,Shuang Wang,Zongliang Du,Xu Cheng,Haibo Wang
In this work, flame-retardant nanoencapsulated phase change materials (NanoPCMs) containing n-octadecane as the core material and poly(methylmethacrylate) (PMMA) as the shell material were successfully fabricated by introducing diethyl bis(2-hydroxyethyl acrylate)amino methylphosphonate (DEAMP) as the crosslinking agent via miniemulsion polymerization. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) analyses confirmed that n-octadecane was successfully encapsulated into the PMMA shell and that the NanoPCMs exhibited a regular spherical profile. The phase change properties, thermal reliability, thermal stability, and flame-retardant properties of NanoPCMs were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), cone calorimeter tests, and limiting oxygen index (LOI) measurements. The DSC results showed that the NanoPCMs possessed a relatively high encapsulation efficiency in the range of 86.5–94.0% for n-octadecane. The thermal properties and durability of the NanoPCMs were almost unchanged after the introduction of DEAMP into the NanoPCMs. The combustion test results showed that the introduction of phosphorus-based flame retardant DEAMP into the NanoPCMs significantly suppressed the heat and smoke releases and, increased the residual weight and LOI value of the EP/NanoPCM composites. In addition, a computer-aided thermal measurement system was created to investigate the thermoregulation properties of the NanoPCMs and the results showed that the addition of NanoPCMs into a gypsum board significantly improved the thermoregulation properties. In conclusion, the flame-retardant NanoPCMs showed considerable potential for thermal energy storage applications, especially in thermoregulated textile and construction fields.
研究领域:
材料科学
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能源工程
·
防火技术
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产品关联
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 32
·25450-25456
·
IF 3.84
Wenqiong Ye,Ling Zhang,Chunzhong Li
SiO2@poly(methyl methacrylate)–reduced graphene oxide (SiO2@PMMA–rGO) composites with outstanding thermal stability, robust mechanical performance and excellent conductivity have been prepared by dispersion polymerization and electrostatic assembly based colloidal blending. The simultaneous construction of well-segregated silica structures and interconnected graphene networks, not only efficiently avoids agglomeration of the incorporated nanofillers, but also ensures enhanced interfacial adhesion between the fillers and the PMMA matrix, endowing the resultant composite with high performance. Specifically, compared to the host polymer, the composite with collaborative structure exhibits high thermal stability, i.e. the decomposition temperature increases by 80 °C and shows robust mechanical properties with a 108% increase in modulus and a 125% improvement in hardness. Besides, an ultra-low percolation threshold of 0.23 vol% is also achieved and the electrical conductivity reached 15.1 S m−1 with only 2.7 vol% graphene loading, which is ∼8 orders of magnitude higher than that for SiO2–PMMA–rGO (where SiO2, PMMA and rGO were simply compounded without forming synergetic structures) with the same rGO loading. These results demonstrate that the SiO2@PMMA–rGO composite has great potential to be applied as mechanical, thermal, and electrical materials.
研究领域:
材料科学
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纳米技术
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2017
·
IF 1.174
Ting Zhang,Minmin Chen,Yu Zhang,Yi Wang
Aiming to identify the validity of fabricating microencapsulated phase change material (PCM) with polymethylmethacrylate (PMMA) by ultraviolet curing emulsion polymerization method using iron (III) chloride as photoinitiator, SA/PMMA microcapsules were prepared and various techniques were employed to determine the ignition mechanism, structural characteristics and thermal properties of the composite. The results shown that the microcapsules containing SA with maximum percentage of 52.20 wt% formed by radical mechanism and only physical interactions existed in the components both in the prepared process and subsequent use. The phase change temperatures and latent heats of the microencapsulated SA were measured as 55.3 °C and 102.1 J·g − 1 for melting, and 48.8 °C and 102.8 J·g − 1 for freezing, respectively. Thermal gravimetric analysis revealed that SA/PMMA has good thermal durability in working temperature range. The results of accelerated thermal cycling test are all shown that the SA/PMMA have excellent thermal reliability and chemical stability although they were subjected 1000 melting/freezing cycles. In summary, the comparable thermal storage ability and good thermal reliability facilitated SA/PMMA to be considered as a viable candidate for thermal energy storage. The successful fabrication of SA/PMMA capsules indicates that ferric chloride is a prominent candidate for synthesizing PMMA containing PCM composite.
研究领域:
材料科学
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能源工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2023
·Vol. 30
·期 6
·1-13
·
IF 2.8
Chen Quan,Zhang Pengying,Zhao Bingbing,Zhao Meng,Ni Lingli,Gao Xiaoyan,Hu Guang,Jiang Xiaowu,Ding Shijie
A novel and facile continuous flow photopolymerization of Pickering emulsion procedure to fabricate nanoporous composite microspheres was induced. Palygorskite (PAL) fibers were chosen as stabilizers in oil phase system that containing of Methyl methacrylate (MMA), (ethylene glycol) diacrylate (EGDMA), Irgacure 819 (I 819, photoinitiator) and toluene (porogenic agent). The influence of PAL concentration to the emulsion stabilities and the morphologies of produced microspheres have been fully investigated. It was observed that in the presence of 1.5 wt% PAL fibers, the formed pickering emulsion provided best conditions to obtain polymerized porous microspheres. Furthermore, N 2 adsorption-desorption isotherms characterization revealed a specific BET surface area of 171 m 2 /g of the resultant microspheres, which suggested the great potential applications of such methodology. Suitable polymerization flow rate is one of the other key parameters to result PMMA/PAL composite microspheres. Additionally, the formation mechanism of the microsphere as well as its porosity has been discussed.
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
Materials
·
2022
·Vol. 15
·期 19
·6962
·
IF 3.748
Kangren Niu,Kuiyan Song
The beeswax used in Chinese traditional hot waxed wood technology has several drawbacks, such as high price, scarce resources, and poor heat resistance. To expand the application of hot waxing technology in the field of wood decoration and protection, polyethylene wax was modified by a grafted maleic anhydride-methyl methacrylate co-monomer. A type of modified polyethylene wax with low cost, high melting point, high stability, and strong polarity suitable for hot waxed wood was prepared as a replacement for beeswax. The effects of the grafting conditions on the chemical properties, thermal properties, chemical structure, and crystallization properties of modified polyethylene wax were studied and compared to those of beeswax. The results show that maleic anhydride-methyl methacrylate co-monomer grafting can effectively improve the acid value of polyethylene wax. For the ratio of two monomers of 1/1, the total amount of monomer of 8 wt%, the amount of initiator of 2 wt%, the reaction temperature of 150 °C, and the acid value of modified polyethylene wax was consistent with that of beeswax, realizing the simulation of the main chemical properties of beeswax. The thermal stability and melting temperature of the modified polyethylene wax are significantly higher than those of beeswax, its crystal structure is similar to that of beeswax, and the cyclic anhydride groups and ester groups introduced by co-monomer grafting endow it with polar groups that play an important role in the wood hot waxing process.Keywords:beeswax;polyethylene wax;grafting;maleic anhydride;methyl methacrylate;thermal and chemical properties
研究领域:
材料科学
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木材科学与技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2016
·Vol. 34
·期 4
·483-490
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IF 1.811
Zhang Li-na,Song Yi-hu,Zheng Qiang
Poly(methyl methacrylate) (PMMA) based ionomers with different lanthanum (La(III)) contents (PMMA-XLa) synthesized by free radical solution polymerization were applied to poly(vinyl chloride) (PVC) resins as a kind of multifunctional aids, and their performances were evaluated by measuring the static stability time, initial discoloration, transparency, fusion behavior and tensile strength of the modified PVC. The ionomers with proper lanthanum (La(III)) contents show a better thermal stability efficiency in comparison with traditional stabilizer lanthanum stearate. Meantime, they can accelerate PVC plasticization more efficiently than PMMA. The rigid PVC products stabilized with the ionomers present good transparency and enhanced tensile strength.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
Catalysts
·
2021
·Vol. 11
·期 2
·162
·
IF 4.146
Huayin Li,Yuan Tan,Xingkun Chen,Wenshao Yang,Chuanqi Huang,Jie Li,Yunjie Ding
Methyl methacrylate (MMA) is an important monomer in fine chemicals. The synthesis of MMA by one-step oxidative esterification from methacrolein with methanol over a heterogeneous catalyst with high activity, selectivity and stability is highly desirable. Herein, Zn-Al-hydrotalcites (HTs)-supported atomically precise Au25nanoclusters with different molar ratios of Zn2+/Al3+were prepared and used as the precursors for this reaction. They exhibited good performances in comparison with the gold catalysts prepared by the deposition precipitation method. The structural and electronic properties were evaluated by various characterization technologies, including X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), in situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) of CO adsorption, X-ray photoelectron spectroscopy (XPS), and CO2temperature-programmed desorption (TPD). The combined characterization results suggested that the adsorption property of gold and the basicity of the catalyst contributes to their high activities. Substrates extended experiments and stability tests implied the potential application of Zn-Al-mixed oxides supported gold catalysts, which paves a new way for supported gold catalyst in the one-step oxidation esterification reaction.Keywords:gold cluster;hydrotalcite;methacrolein;methyl methacrylate;oxidative esterification
研究领域:
化学工程
·
催化化学
✓ 已验证
DOI
高影响因子
ENERGY
·
2012
·
IF 3.487
Xiaolin Qiu,Wei Li,Guolin Song,Xiaodong Chu,Guoyi Tang
Microcapsules containing n-octadecane with different methylmethacrylate (MMA (methyl methacrylate))-based copolymer shells were fabricated by a suspension-like polymerization. Butyl acrylate (BA), butyl methacrylate (BMA), lauryl methacrylate (LMA) and stearyl methacrylate (SMA) were employed as monomers to copolymerize with MMA . Pentaerythritol tetraacrylate (PETRA) was employed as a crosslinking agent. The (microencapsulted phase change materials) MicroPCMs were characterized using Fourier transformed infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Thermal properties and thermal resistances of MicroPCMs were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), respectively. Phase change enthalpies and PCM contents of MicroPCMs increased with the length decreasing of the side chain of the monomers . The n-octadecane content of as much as 77.3% can be obtained in the crosslinked MicroPCMs with P(MMA-co-BMA) as shell, and accompanied by the highest melting enthalpy (173.7 J/g) and crystallization enthalpy (174.4 J/g). Heat capacities of crosslinked MicroPCMs are higher than those of their uncrosslinked counterparts. The crosslinked MicroPCMs exhibit significantly greater thermal stabilities compared with their uncrosslinked counterparts and the n-ontadecane bulk. The crosslinked MicroPCMs with P(MMA-co-SMA) displays the highest thermal resistance temperature up to 255 °C. Therefore, MicroPCMs with MMA-based copolymer as shells, especially crosslinked copolymer shells, show excellent potentials for thermal energy storage .
研究领域:
材料科学
·
能源工程
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2014
·Vol. 52
·期 7
·1020-1027
·
IF 3.245
Danfeng Yang,Dan He,Yonggui Liao,Zhigang Xue,Xingping Zhou,Xiaolin Xie
The polar solvents, N -methylpyrrolidone (NMP), N , N -dimethylformamide (DMF), and acetonitrile (CH 3 CN) were used as ligands for iron(III)-mediated activators generated by electron transfer atom transfer radical polymerizations (AGET ATRPs) of methyl methacrylate (MMA) with various initiators and reducing agents. Polymerizations were conducted with a molar ratio of [MMA] 0 /[initiator] 0 /[FeBr 3 ] 0 /[reducing agent] 0 = 100:1:1:0.5 and a volume ratio of MMA/solvent = 2:1 at 60 °C to investigate the effects of initiator, solvent and reducing agent, and most of the systems showed the typical features of “living”/controlled radical polymerization. In order to get a deeper understanding of the mechanism, the amount of the reducing agent was changed to study the polymerization behavior. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52 , 1020–1027
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
Applied Sciences-Basel
·
2019
·Vol. 9
·期 3
·603
·
IF 2.217
Wenzhong Ma,Yuchen Zhao,Zhiwei Zhu,Lingxiang Guo,Zheng Cao,Yanping Xia,Haicun Yang,Fanghong Gong,Jing Zhong
An efficient synthesis route was developed for the preparation of multiwalled carbon nanotube (MWCNT) nanohybrids using azide-terminated poly(methyl methacrylate) (PMMA) via a combination of reversible addition fragmentation chain transfer (RAFT) and the click reaction. A novel azido-functionalized chain transfer agent (DMP-N3) was prepared and subsequently employed to mediate the RAFT polymerizations of methyl methacrylate (MMA). The RAFT polymerizations exhibited first-order kinetics and a linear molecular weight dependence with the conversion. The kinetic results show that the grafting percentage of PMMA on the MWCNTs surface grows along with the increase of the reaction time. Even at 50 °C, the grafting rate of azide-terminated PMMA is comparatively fast in the course of the click reaction, with the alkyne groups adhered to MWCNTs in less than 24 h. The successful functionalization of PMMA onto MWCNT was proved by FTIR, while TGA was employed to calculate the grafting degree of PMMA chains (the highest GP = 21.9%). Compared with the pristine MWCNTs, a thicker diameter of the MWCNTs-g-PMMA was observed by TEM, which confirmed the grafted PMMA chain to the surface of nanotubes. Therefore, the MWCNTs-g-PMMA could be dispersed and stably suspended in water.Keywords:multi-wall carbon nanotube (MWCNT);azide-alkyne click chemistry;RAFT polymerization;PMMA
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
REACTIVE & FUNCTIONAL POLYMERS
·
2020
·
IF 3.333
Wang Xie,Biwu Wang,Yuan Liu,Qi Wang,Zhongqiang Yang
It is challenge for improving the flame retardancy of poly(methyl methacrylate) (PMMA), and meanwhile keeping its inherent high transparency. In this paper, a phosphorus containing monomer synthesized by our group is introduced into PMMA via radical copolymerization to prepare a flame retardant and transparent modified PMMA. The structure and properties of the obtained copolymer is characterized. With 15% mol of the phosphorus containing monomer involved, the copolymer exhibits a comparable transparency with PMMA, and its limit oxygen index (LOI) reaches 27.5% and passes UL-94 V-0. The flame retardance mechanism of the copolymer is further analyzed by thermogravimetric analysis (TGA), cone calorimetry , scanning electron microscope (SEM) and Fourier transform infrared light spectrograph (FT-IR).
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
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Gang Wang,Zengxi Li,Chunshan Li,Suojiang Zhang
The activation and selectivity are the challenging problems always existing in the utilization of methanol as C 1 resource. Herein, a novel cobalt complex catalyzed process for preparation of methyl acrylate from methyl acetate and methanol at 50 °C–80 °C was firstly developed. Such cobalt complex stabilized with a PN 5 P-type pincer ligand, which can be easily prepared in gram scale, has high catalytic performance with the loading amount of only 5 mol.%. Systematic mechanism investigation revealed the cobalt complex activated by sodium methoxide via salt elimination could simultaneously interact with and catalyze the dehydrogenation of two-fold methanol into formaldehyde, followed by proceeding aldol condensation with methyl acetate in the presence of sodium methoxide. Besides the reaction atmosphere of O 2 was proved to be crucial for preventing the further hydrogenation of methyl acrylate into methyl propionate. Also, the mechanism-based kinetic model indicated the dehydrogenation of methanol was rate-controlling step with the activation energy of 89.0 ± 1.1 kJ/mol.
研究领域:
化学工程
·
催化化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）