POLYMER SCIENCE SERIES B
·
2019
·Vol. 61
·期 3
·240-246
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IF 0.907
Xian Rong Shen,Xiang Yi Xin,Gao Jian Gang
Abstract Supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) of methyl acrylate was successfully performed in inexpensive, eco-friendly polyethylene glycol solvents and catalyzed by a mixed sulfite/CuBr 2 system at room temperature. The presence of polyethylene glycol in the reaction mixtures allowed fast and controlled polymerizations throughout the whole reaction time. Remarkably, a fast polymerization can be achieved with a monomer conversion reaching 90% in only 50 min using PEG 200 as the reaction solvent. The controlled character of the ATRP of methyl acrylate was confirmed by the linear increase in molecular weight with monomer conversion, the narrow molecular weight distributions ( M w / M n = 1.15) and the results of chain extension experiments. 1 H NMR analysis also confirmed the molecular structure and chain-end functionality of the obtained polymers, and the effects of PEG molecular weight and inorganic sulfites on the polymerization behavior were investigated.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Yufei Tang,Lei Chen,Zihao Duan,Kang Zhao,Zixiang Wu
The introduction of BaTiO 3 (BT) particles into biomaterials, such as polymethyl methacrylate (PMMA) bone cement , is among the effective ways to improve their osteoinductivity. However, excessive addition leads to mechanical degradation . An important problem to solve is the manner by which piezoelectric properties matching human bones can be obtained under the premise of sufficient mechanical properties . The piezoelectric effect is obtained by adding BT particles into PMMA bone cement. The piezoelectric coefficient close to the human bone is obtained at a relatively low BT addition amount by adding graphene on this basis. High mechanical properties can also be obtained. Graphene increases the piezoelectric coefficient by increasing the conductivity, dielectric constant, and effective polarization voltage of graphene (G)/BT(BaTiO 3 )/PMMA bio-piezoelectric composites. The compression strength of the aforementioned composites increases from 83.5 MPa to 89.5 MPa after the addition of 0.5 vol% graphene, and the requirements of bone implant materials were met. G/BT/PMMA bio-piezoelectric composites have no cytotoxicity, and graphene can also promote cell adhesion and proliferation on the composite's surface. The polarized bio-piezoelectric composites can improve cell morphology and promote cell proliferation . The number of cells increases with increasing piezoelectric coefficient. The composite has potential application prospects in various fields, such as oral cavity and bone implant.
研究领域:
生物医学工程
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材料科学
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产品关联
DOI
高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
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2022
·
IF 9.463
Kang Zhang,Yan Wang,Yuling Xiao,Yapeng Zheng,Jingyi Lu,Chao Ma,Yuan Hu
A novel phosphorus/nitrogen-containing hyperbranched polyphenylphosphate (PHP) was synthesized and it was used with 3-isocyanatopropyltrimethoxysilane (ICPTMOS) to prepare transparent and flame retardant coating for poly(methyl methacrylate) (PMMA). The content of PHP and ICPTMOS was changed to investigate the influence of silicon content on the performance of PMMA coating complexes. All coated PMMA samples are highly transparent and the pencil hardness of coatings increases with the increment of silicon content. The cone calorimeter test results indicate that the relatively low silicon content in PMMA coatings is conducive to the simultaneous reduction of heat release and smoke production. Moreover, the coatings can effectively protect the PMMA matrix in fire and with only 3.2% PHP replaced by ICPTMOS (0.08 g) in coating formulation, the fire resistance time of corresponding coated PMMA sample is extended to 1500 s. This work provides a highly-efficient strategy to concurrently improve fire safety, transparency and hardness of coating.
研究领域:
材料科学
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火灾安全工程
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产品关联
DOI
高影响因子
POLYMER COMPOSITES
·
2014
·Vol. 36
·期 9
·1675-1684
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IF 1.455
Lili Qin,Guohua Li,Jun Hou,Xiaoyan Yu,Huili Ding,Qingxin Zhang,Nongyue Wang,Xiongwei Qu
Poly (methyl methacrylate)/boron nitride (PMMA/BN) composites were prepared by dispersing BN particles into methyl methacrylate monomer phase by bulk polymerization method. BN particles modified with silane coupling agent, γ-methacryloxypropyl trimethoxy silane, were characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. Effects of modified BN particle content on thermal conductivity were investigated, and the experimental values were compared with those of theoretical and empirical models. With 16 wt% of BN particles, the thermal conductivity of the composite was 0.53 W/(m·K), 1.8 times higher than that of pure PMMA. The microstructures of the PMMA/BN composites were examined by scanning electron microscopy, energy-dispersive X-ray analysis, and transmission electron microscopy. Dynamic mechanical analysis and thermogravimetric analysis traces also corroborated the confinement of the polymer in an inorganic layer by exhibiting an increase in glass-transition temperatures and weight loss temperatures in the thermogram. Mechanical properties and electrical insulation property of the PMMA/BN composites were also determined. These results showed that PMMA/BN composites may offer new technology and business opportunities. POLYM. COMPOS., 36:1675–1684, 2015. © 2014 Society of Plastics Engineers
研究领域:
材料科学
·
高分子化学
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产品关联
DOI
高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
·
2022
·Vol. 34
·期 2
·549-558
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IF 3.348
Wang Xie,Yuan Liu,Mingming Yu,Qi Wang
The synthesis of intrinsic flame retardant copolymer by copolymerization with reactive flame retardants is the most potential method to prepare transparent and flame retardant poly (methyl methacrylate) (PMMA) at present，but the main challenge of this method is that the copolymer usually has poor mechanical properties and heat resistance. In this work, the hydrogen bond enhancement strategy is adopted, and the flame retardant PMMA with excellent comprehensive properties is obtained by ternary copolymerization with methyl methacrylate (MMA) as matrix unit, diethyl (methacryloyloxymethyl) phosphonate (DEP) as flame retardant unit and methacrylamide (MAA) as hydrogen bond unit. Due to the formation of intermolecular hydrogen bond via MAA unit, the storage modulus, flexural strength and impact strength of the terpolymer containing 15 mol% MAA are 48%, 19%, and 24% higher than those of the copolymer of MMA and DEP, and its hardness, glass transition temperature and load thermal deformation temperature (increased by 7°C) are also superior. Moreover, owing to the gas-phase dilution and charring flame retardancy of MAA unit, the terpolymer shows increased limiting oxygen index (24.3%) and UL94 rating (V-1). This work not only provides a promising flame retardant PMMA for practical application, but also offers a new strategy to design flame retardant polymers with good mechanical properties.
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Luming Wang,Yuhang Bian,Zhenyu Wu,Zengxi Li,Gang Wang,Chunshan Li
Hydroesterification of ethylene with carbon monoxide (CO) and methanol (MeOH) for preparing methyl propionate (MP) has stimulated researcher’s attention in recent years. Herein, the palladium-phosphine catalyzed ethylene hydroesterification with the promotion of acidic poly ionic liquids (APILs) for direct MP synthesis was developed. Series of APILs samples having different anions and acid densities were prepared and their structural properties were characterized by employing NMR, FTIR, TG and XPS. The anion type and acid density in APILs shown great influence on the catalytic performance due to the electronic effect and proton supply capacity related to Pd-H species formation. The hydrogen bond formed through the interaction between the anion of APILs and methanol could effectively promote the ethylene hydroesterification. The substrate extension experiments revealed the polarity and steric hindrance of alcohol would impact ethylene conversion. The mechanistic studies using in-situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) unraveled that the hydroesterification started with the activation of palladium complex to Pd-H species by CO, followed by the sequential formation of Pd-C 2 H 4 , Pd-alkyl and Pd-acyl intermediate species and consequential product MP. As a result, 94.4 % ethylene conversion could be achieved with 100 % selectivity toward MP at 80 °C and 2 MPa. No obvious deactivation behavior was observed for this kind of palladium catalyst after ten recycling experiments. The kinetic studies revealed the activation energy of ethylene hydroesterification is 59.3 kJ/mol.
研究领域:
催化化学
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材料科学
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物理化学
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产品关联
DOI
高影响因子
Nanomaterials
·
2023
·Vol. 13
·期 16
·2372
·
IF 5.3
Jiaming Wang,Li Zou,Meili Yang,Jiajie Cheng,Yufan Jiang,Guangdong Huang,Jingjing Dong
All-inorganic perovskite quantum dots (CsPbX3QDs) (X = Cl, Br, I) have the advantages of adjustable emission position, narrow emission spectrum, high fluorescence quantum efficiency (PLQY), easy preparation, and elevated defect tolerance; therefore, they are widely used in optoelectronic devices, such as solar cells, light-emitting diodes, and lasers. However, their stability still constrains their development due to their intrinsic crystal structure, ionic exchange of surface ligands, and exceptional sensitivity to environmental factors, such as light, water, oxygen, and heat. Therefore, in this paper, we investigate the stability improvement of CsPbX3QDs and apply fabricated high-efficiency, stable perovskite QDs to solar cells to improve the performance of the cells further. In this paper, we focus on CsPbBr3QDs with intrinsic extreme stability and optimize CsPbBr3QDs using strategies, such as Mn+doping, ligand regulation, and polymer encapsulation, which can improve optical properties while ensuring their stability. The test results show that the above five methods can improve the strength and luminescence performance of QDs, with the best stability achieved when PMMA encapsulates QDs with a ratio of PMMA = 2:1 and PLQY increases from 60.2% to 90.1%.Keywords:perovskite quantum dots;CsPbBr3;PMMA;optical properties;stability
研究领域:
材料科学
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光电子学
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产品关联
DOI
PubMed
高影响因子
IRANIAN POLYMER JOURNAL
·
2018
·Vol. 27
·期 11
·881-887
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IF 1.278
Zeng Le-Lin,Xie Wan-Yun,Yang Cai-Xia,Liang Enxiang,Wang Guo-Xiang
In this study, a novel photocatalyst, pentarylenebis(dicarboximide) dye: (1,6,13,18-tetra(4-(2,3,3-trimethylbut-2-yl)phenoxy)- N,N ’-(2,6-diisopropylphenyl)-pentarylene-3,4,15,16-tetracarboxidiimide) (TTPDPT), was first used in metal-free photoinduced atom transfer radical polymerization (ATRP) of methyl methacrylates (MMA). The initiator was methyl α-bromoisobutyrate (MBI) and the light source was mild near-infrared (NIR) light irradiation ( λ max ≈ 870 nm). The TTPDPT-mediated ATRP relies on in situ photoreduction of a MBI through an electron transfer process to generate the desired alkyl radical, which could induce polymerization of the monomer. The photoinduced metal-free ATRP of MMA shows typical characteristics of controlled free radical polymerization, showing the linear evolution of number-average molecular weight ( M n,GPC ) with monomer conversion, where polymers with predetermined degree of polymerization have well-controlled molecular weights and narrow molecular weight distribution ( M w / M n ). The photoinduced metal-free ATRP of MMA can be carried out with just ppm level of TTPDPT. The polymerization initiation and propagation can be operated by the aid of pulsed light sequences while NIR light source was used to promote carbon–carbon bond formation and to produce poly(methyl methacrylate) (PMMA) with M w / M n as low as 1.5. The synthesized PMMA was characterized by 1 H nuclear magnetic resonance ( 1 H NMR). The resultant PMMA contained a bromide end group that can be employed to reinitiate styrene polymerization to produce block copolymers through chain extension experiments.
研究领域:
高分子化学
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材料科学
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光化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Xiongwei Wang,Peiyi Wu
Covalent modification of nanofillers with polymeric chains is believed an efficient method to improve their dispersion and interfacial adhesion in polymer matrix, which both play critical roles in attaining the high heat-conducting properties of the polymer composites. However, the facile graft of polymeric chains onto nanofillers through a one-step approach is still faced with large challenges, especially for the chemically inert carbon nanotubes (CNTs), graphene and boron nitrides. In this work, one-step photo-mediated graft polymerization was used to graft PMMA chains onto the fluorinated CNTs (FCNTs) by using C-F bonds as the initiating sites. It was found that covalent functionalization greatly improves the dispersion of FCNTs in PMMA resin by reinforcing the interfacial interaction between them. Owing to the reduced thermal resistance, the thermal conductivity of functionalized FCNTs based composite outperforms the composite filled with virginal FCNTs in the whole range of filler fractions. Moreover, the PMMA functionalization contributes to strengthening the mechanical performances of the composite, and despite the amount of filler, the composites with functionalized FCNTs always show an excellent electrical insulating property.
研究领域:
材料科学
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高分子化学
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产品关联
DOI
高影响因子
ChemPlusChem
·
2015
·Vol. 81
·期 2
·161-165
·
IF 3.026
Shaoyun Chen,Chenglong Hu,Weihong Zhang,Jian Chen
Graphical Silver linings : A large-area, self-assembling, octahedral aggregate composed of poly(methyl methacrylate) nanospheres (PMMA-NS) was constructed by a one-step electrodeposition approach using an aqueous solution of AgNO 3 and PMMA-NS as sacrificial electrolytes. The surface chain geometry of the product was revealed by Raman spectroscopy, and its excellent adsorptive properties were studied (see figures). A large-area, self-assembling, octahedral aggregate composed of poly(methyl methacrylate) nanospheres (PMMA-NS) was constructed by using a one-step electrodeposition approach from an aqueous solution containing AgNO 3 and PMMA-NS as sacrificial electrolytes. The surface chain geometry of the product was revealed by Raman spectroscopy. The results revealed that the orientation of chains of the PMMA-NS octahedron is different from that of the nonaggregated PMMA-NS because of the interfacial interactions between the polymer chain and Ag metal. This can be explained by the crystal surface free energy of the octahedral Ag substrate, which gives rise to diverse conformations of the PMMA molecular chain at different surface regions of the silver substrate. In addition, the adsorptive properties of PMMA-NS octahedra are such that the adsorbent–adsorbate system is cost-effective, efficient and fast for the removal of dyes from contaminated wastewater.
研究领域:
材料科学
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表面化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER
·
2023
·
IF 4.6
Jun Zhong,Xinyue Zhang,Xiaofeng Yu,Xuanyu Shi,Shihao Sun,Li Yang,Min Zuo,Yihu Song,Qiang Zheng
The selective distribution of silica nanoparticles(NPs) grafted with crosslinked poly(methyl methacrylate) (PMMA) in PMMA/poly(styrene- co -acrylonitrile) (SAN) blend is investigated by varying the crosslinking degree of grafted PMMA. NPs grafted with highly crosslinked PMMA chains mainly tend to be located in the PMMA-rich domains, while NPs grafted with linear PMMA chains mainly tend to be distributed at the interface of blend matrix. NPs grafted with slightly crosslinked chains are located partially at the interface and partially in the PMMA-rich domains. The deviation between the theoretical predication and actual location of modified NPs may be related with the heterogeneity of miniemulsion polymerization. Furthermore, different location of three modified NPs induced by different grafted chain structure may result in their various compatibilization effects on PMMA/SAN blend. NPs grafted with linear or slightly crosslinked PMMA aggregate at the interface of blend matrix to form the jamming structure and further inhibit completely the domain coarsening.
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2024
·
IF 4.1
Huimin Xue,Guidong Li,Lifei Liu,Tong Feng,Chun Li,Jiayang Sui,Weizhen Zhao
The stereochemistry of polymethyl methacrylate (PMMA) has a profound influence over its material properties; however, the pursuit of high tacticity in bulk free radical polymerization presents a formidable challenge. Consequently, the procurement of a methodology that facilitates the synthesis of highly tactic polymers during bulk free radical polymerization is both desirable and challenging. In this investigation, the propagation of methyl methacrylate (MMA) within an ionic liquids (ILs) medium was employed via bulk free radical polymerization to harness tacticity. The reactivity of polymerization and the propensity for isotactic polymer formation were potentiated by the incorporation of ILs, specifically 1-octyl-3-methylimidazolium hexafluorophosphate as an additive. The resultant polymer exhibited a triad isotacticity (mm) of 33%, achieved in the presence of a 5 wt% concentration of 1-octyl-3-methylimidazolium hexafluorophosphate. The isotactic selectivity of the ILs appeared to arise from their dynamic interplay with the monomeric or polymer chains, an interaction elucidated by 1 H NMR and DFT analyses. The research imparts critical understanding into the manipulation of PMMA tacticity and presents an enaging prospect for the production of highly tactic polymers via bulk free radical polymerization.
研究领域:
材料科学
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高分子化学
✓ 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）