RSC Advances
·
2013
·Vol. 4
·期 1
·510-515
·
IF 2.562
Huan Wang,Baoqing Shentu,Zhixue Weng
A one-pot synthetic approach for the preparation of poly(2,6-dimethyl-1,4-phenylene oxide)/polystyrene (PPO/PS) alloy in aqueous medium was developed. The method was based on the combination of the oxidative coupling polymerization of 2,6-dimethylphenol (DMP) to form PPO in the presence of a reactive swelling agent, styrene (St), and in situ reverse atom transfer radical polymerization (RATRP) of St initiated by 2,2′-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride (AIBI) in alkaline aqueous solution. The complex of CuCl2 and 4-dimethylaminopyridine (DMAP) was utilized as the catalyst to catalyze the two types of polymerization mentioned above. Oxygen was employed as the sole oxidant to synthesize PPO. The introduction of St during the oxidative polymerization of DMP could increase the molecular weight of PPO. Finally thermodynamically compatible PPO/PS alloy was successfully prepared.
研究领域:
高分子化学
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材料科学
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DOI
高影响因子
POLYMER
·
2024
·
IF 4.1
Hongjing Pei,Yanmei Han,Yong Liu,Xu Han
Although copper-aliphatic amines have been extensively used as catalysts for the polymerization of 2,6-dimethylphenol (DMP) to poly (2,6-dimethyl-1,4-phenylene oxide) (PPO), the high polydispersity index (PDI) of PPO and high content of 3,3′,5,5′-tetramethyl-4,4'diphenoquinone (DPQ) in PPO significantly affect the physical properties of PPO . In this study, different CuBr-aromatic amines have been used as catalysts for synthesizing PPO. CuBr– N -methylbenzylamine shows a high yield of PPO (94.4 %) with the low DPQ yield (0.46 %) and PDI (1.33) in the presence of 0.1 % H 2 O, which facilitates the formation of dinuclear Cu(Ⅱ) species. In addition, the low dielectric constants (2.43 and 2.25) and low dielectric loss factors (1.07 × 10 −3 and 1.29 × 10 −3 ) of the PPO synthesized by CuBr– N -methylbenzylamine and CuBr-4-aminopyridine again indicate that aromatic amines are more appropriate for the synthesis of PPO with superior dielectric properties . Meanwhile, the high-molecular-weight PPO can be successfully redistributed to low-molecular-weight PPO by adding DMP in the presence of CuBr– N -methylbenzylamine, and the decreased T g values from 212.5 to 187.8 °C with decreasing M n values from 2.7 × 10 4 to 5.5 × 10 3 indicate the improved processability of the low-molecular-weight PPO. This study provides new insights on important roles of aromatic amines in the synthesis of PPO.
研究领域:
高分子化学
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材料科学
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产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2014
·Vol. 2
·期 43
·18562-18573
·
IF 0
Lijia Yang,Beibei Tang,Peiyi Wu
In this work, graphene oxide (GO) was first functionalized with branched polyethyleneimine (PEI). The obtained PEI–GO was incorporated into a brominated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) matrix by a covalent bond interaction to form a cross-linking network. Then, a novel ultrafiltration (UF) membrane was prepared via casting and phase-inversion methods. The PEI–GO/BPPO membrane showed highly improved water flux, which was almost 6 times higher than that of the pristine BPPO membrane and 2.5 times higher than that of the GO/BPPO membrane, whereas the rejection of PEI–GO/BPPO membrane was still maintained at a high level. The improvement of membrane performance could be attributed to the special property of PEI–GO and the interactions between PEI–GO and the BPPO matrix. First, a cross-linking network of PEI–GO/BPPO membrane was formed because of the reaction between PEI–GO and the BPPO matrix to provide passageways for water rapidly passing through. Second, the high hydrophilicity of PEI–GO could accelerate the exchange rate between solvent and non-solvent, resulting in a rougher and more hydrophilic surface, higher porosity and a more porous structure. Third, the good dispersion and compatibility of PEI–GO promoted the formation of a uniform structure with fewer defects. Proper molecular weight of PEI was very important for the modification of GO, subsequently resulting in an overall enhancement in membrane performance. Anti-fouling experiments and stability tests of the membranes were also conducted. All of these results were confirmed by various characterizations, such as SEM, TEM, AFM and, etc.
研究领域:
材料科学
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环境工程
✓ 已验证
DOI
JOURNAL OF POLYMER RESEARCH
·
2021
·Vol. 28
·期 7
·1-11
·
IF 3.097
Yu Xueyi,Fang Zeming,Qin Yijing,Lu Dong,Liu Qianfa,Luo Li,Lin Zhiyong,Wang Ke
Thermosetting Polyphenylene oxide (PPO)/Triallyl isocyanurate (TAIC) based composite systems have attracted considerable attentions in recent years due to their excellent performance as the substrate for printed circuit boards (PCBs) used for 5G networks. Since the residuals of -OH and -C = C- groups have significant effects on the properties of the substrate, especially the dielectric properties and thermal stability, it is critical to establish valid methods for characterizing these systems. In this work, FTIR, 1 H-NMR and 13 C-SSNMR were employed to qualitatively and quantitatively characterize the -OH and -C = C- groups in the methyl methacrylate (MMA) terminated PPO/TAIC co-cured system. No -OH groups were detected on the molecular chains of PPO oligomers, indicating that almost all the phenolic hydroxyl groups in the precursor had been substituted. During the curing, no new -OH groups were generated but some -C = C- groups were left unreacted. FTIR quantitative analysis showed that these -C = C- groups belonged to TAIC and the residual ratio of -C = C- could be as high as 60.37%.
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
SEPARATION AND PURIFICATION TECHNOLOGY
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2022
·
IF 9.136
Yansu Lan,Die Zhou,Longhuan Lai,Huanhuan Qi,Lei Xia,Stef Depuydt,Bart Van der Bruggen,Yan Zhao
Bromide recovery from waste streams is crucial for both environmental and economic reasons. Membrane technology has shown great potential in achieving efficient ion separation, credited to the use of separation membranes with well-defined pore structure down to molecular level and surface charge properties. Herein, a class of novel anion exchange membranes (AEMs) was fabricated by brominated poly (2,6-dimethyl-1, 4-phenyl oxide) (BPPO) and different content of 4-hydroxy-1-methylpiperidine (HMP) via the chemical substitution reaction for Br - recovery. The resulting membrane (HMP@BPPO-0.1) had an ion exchange capacity of 1.69 mmol g −1 , a water content of 14.4 %, a swelling rate of 4.7 %, a surface electrical resistance of 3.68 Ω cm 2 and a limiting current density of 28.4 mA cm −2 . In addition, under a constant voltage of 15.0 V for 180 min in electrodialysis, the removal ratio of NaBr solution was 98.15 %, which was higher than that of the commercial AEM (ASE) (97.1 %) under the same testing conditions. To evaluate the Br - selectivity, the membranes were tested for an initial concentration of 50 mM of NaCl, NaBr and Na 2 SO 4 in a mixed solution with a constant current density of 2.5 mA cm −2 , 5.0 mA cm −2 and 10.0 mA cm −2 . The results showed that the permselectivity of the HMP@BPPO-0.1 for 100 min was as high as 12.6 (Br - /SO 4 2- ) and 1.20 (Br - /Cl - ) under the 5.0 mA cm −2 electric field, and the ion permeation rate of Cl - , Br - and SO 4 2- were 0.78, 1.20 and 0.20 mol −1 m -2 h −1 , respectively. Compared to the ASE membrane and the resulting membrane with negatively charged modification layer, this work suggests novel ideas in fabricating a membrane with Br - selectivity in view of resource recovery.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2025
·
IF 4.5
Ya-Qi Wang,Qing He,Zhi-Yang Zhang,Lei Zhang,Na-Juan Yuan,Yong Liu,Hai-Tao Ren,Xu Han
Although the low molecular weight poly(2,6-dimethyl-1,4-phenyl oxide) (LMW-PPO) has been extensively applied in the field of 5G communication, the complicated procedures involved in the synthesis of LMW-PPO and efficient recovery of the homogeneous catalysts are still challenging nowadays. In this study, five ionic liquids (ILs) have been successfully synthesized, and LWM-PPO is directly synthesized using different Cu(OAc) 2 -ILs complexes as catalysts. Among them, Cu(OAc) 2 - IL(a) not only exhibits the high yield of LWM-PPO (83.68%, M n =3.6✕10 3 ) with the low 3,3’,5,5’-tetramethyl-4,4’-diphenoquinone (DPQ) yield (0.12%) and polydispersity index (PDI, 1.39) in methanol, but also maintains high stability after being recycled for 5 times. In addition, with increasing H 2 O contents in the system from 1.0% to 5.0%, the M n values of PPO decrease from 2.9✕10 3 to 2.4✕10 3 with the narrow PDI values in the range of 1.22-1.45, indicating that trace H 2 O effectively promotes the formation of binuclear Cu(II) complex between Cu(OAc) 2 ·H 2 O and ILs, which then polymerizes 2,6-dimethylphenol (DMP) to LMW-PPO. The synthesized LMW-PPO exhibits high thermostability ( T d5% =427.07-430.52°C), low glass transition temperature ( T g =167.6-180.3°C), and low dielectric constant ( D k =2.14-2.64, 1 GHz) and dielectric loss ( D f =2.83✕10 -3 -4.91✕10 -3 , 1 GHZ), indicating that it is more appropriate to be used in the field of 5G communication. This study provides new insight on the importance of ILs in direct synthesis of LMW-PPO with high performances.
研究领域:
材料科学
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化学工程
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高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2024
·
IF 8.4
Huimin Ruan,Shangshang Gao,Yeyang Li,Shuaijun Yu,Junbin Liao,Edison Huixiang Ang,Yanqing Xu,Jiangnan Shen
Proton blocking anion exchange membranes (AEMs), which are employed in electrodialysis technology, show promise in acid recovery from industrial waste. A series of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) membranes were prepared using (3-aminopropyl)trimethoxysilane (APTMS) and weakly functionalized bases including N-butylimidazole (N-BuIm). Were networked to create AEMs with low leak rates. It was discovered that the appropriate concentration of siloxane crosslinker raised the membrane matrix's density and lowered the AEM matrix's hydrophilicity. Thermogravimetric measurements and water absorption have confirmed this, and the membranes in this series even swell up to 8.61 %. The maximum H + concentration concentrated by the cross-linked AEM (BPPO/5Si) during the ED with a current density of 10 mA ∙ cm −2 was 2.35 M, which was higher than the concentration concentrated by the uncross-linked AEM (BPPO/OSi), which was 1.90 M (beginning concentration: 1.00 M). The current efficiency was 44.8 % and the energy consumption was only 1.81 kW ∙h∙kg − 1 . A balance between proton blocking and SO 4 2− ions transport was achieved by the optimized AEM, which exhibited increased hydrophobicity and smaller ion clusters. The improved AEM was found to have fewer ionic clusters and greater hydrophobicity. For cross-linked AEMs, a trade-off between SO 4 2− ions transport and proton blocking was thus accomplished. This work is thought to offer direction for developing sophisticated proton blocking AEMs.
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
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2018
·Vol. 165
·期 5
·F350
·
IF 3.662
Yunfei Yang,Yixin Xu,Niya Ye,Dengji Zhang,Jingshuai Yang,Ronghuan He
Quaternization of poly(2,6-dimethyl-1,4-phenylene oxide)s (PPOs) with a series of saturated heterocyclic compounds was carried out via the Mannich reaction to fabricate anion exchange membranes (AEMs) with high alkaline chemical stability and ion conductivity. The heterocyclic quaternary ammonium cations include 1-methylpyrrolidinium (MPy), 1-ethylpyrrolidinium (EPy), 1-butylpyrrolidinium (BPy), 1-methylpiperidinium (MPrD), 1-ethylpiperidinium (EPrD) and N-methylmorpholinium (NMM). For comparison, trimethylammonium (TMA) and 1-methylimidazolium (MeIm) functionalized PPO membranes were fabricated as well. The physicochemical properties of the prepared membranes were investigated in terms of water uptake, swelling, ion exchange capacity, mechanical properties, conductivity and tolerance to alkalies. The AEMs having saturated heterocyclic quaternary ammonium groups exhibited better resistance to nucleopholic attack of hydroxide ions than PPO-TMA and PPO-MeIm membranes, especially the PPO-MPy membrane, which retained its initial conductivity of 87.5% after immersed in 1M KOH at 80°C for 508 h.
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
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2013
·
IF 2.206
Yijian Wu,Lei Gui,Huan Wang,Baoqing Shentu,Zhixue Weng
A novel and convenient synthetic method for the preparation of α,ω-bis(2,6-dimethylphenol)-poly(2,6-dimethyl-1,4-phenylene oxide) (PPO-2OH) oligomer in water is presented. It is based on the oxidative copolymerization of 2,6-dimethylphenol (DMP) and aromatic diols in the presence of Cu-ethylene diamine tetraacetic acid catalyst in water. It was found that the mole fraction of PPO-2OH in the product was affected by species of aromatic diols and mole ratio of DMP to aromatic diols. Species and concentration of surfactants were demonstrated to be significant factors that would influence molecular weight (Mn) and yield of PPO-2OH. The synthesized PPO-2OH was end-group modified with methacryloylchloride (MAC) to obtain dimethacryloyl chloride telechelic PPO (PPO-2MAC). The relationship between glass transition temperature (Tg) and Mn of PPO-2OH is in good agreement with the Flory–Fox equation. Thermal polymerized low-molecular-weight PPO-2MAC has a constant Tg at about 208 °C.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
SOLID STATE IONICS
·
2019
·
IF 2.886
Xi Zhu,Chunhui Shen,Shanjun Gao,Huaiyang Jin,Xiangze Cheng,Chenliang Gong
A series of high-temperature proton exchange membranes were prepared by incorporating phosphonic acid functionalized siloxane synthesized from Amino Trimethylene Phosphonic Acid (ATMP) and 3-Aminopropyltriethoxysilane (APTES) into cross-linked 1-Methylimidazole-functionalized poly(2,6-dimethyl-1,4-phenyleneoxide) (PPO) backbone. The structural characteristics of membranes were investigated using FT-IR, 1 H NMR and XRD , indicating that ATMP and backbones of membranes were successfully immobilized into cross-linking Si-O-Si networks formed by hydrolysis-polycondensation of APTES. The resultant membranes named as HTM-X exhibited superior oxidative resistance, mechanical properties and dimensional stability, even the thermal stability was up to 210 °C. The proton conductivities of membranes were also measured under different temperature. The result showed that HTM-15 membrane, whose content of phosphonic acid functionalized siloxane was 15 wt%, possessed the highest proton conductivity of 8.48 × 10 −2 S cm −1 at 160 °C and low relative humidity (5%) with the contribution of dual proton transfer channels of acid-base pairs and continuous hydrogen bond networks. Therefore, this novel membrane acts as a potential candidate for proton exchange membranes operating at elevated temperature.
研究领域:
材料科学
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化学工程
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2019
·
IF 3.771
Zhengfang Zhu,Peng Cui,Yu Lu,Jianrong Wu,Jing Zeng,Weiye Ma,Xinsheng Zhao,Yuanqin Zhu
To develop a facile route towards anion conductive polymers containing multi-cation side chains, novel anion conductive poly (2,6-dimethylphenylene oxide)s (DQPPO-x-I) was prepared from a clickable di-quaternized side-chain precursor, via Cu(I)-catalyzed azide-alkyne click chemistry. The new precursor was synthesized from commercially available 2-{[2-(dimethylamino)ethyl]methylamino}ethanol and 3-bromopropyne via nucleophilic substitution and Menshutkin reaction . The chemical structures of the precursor and DQPPO-x-I polymers were characterized by 1 H NMR and FT-IR. Small angle X-ray scattering and transmission electron microscopy revealed that the obvious micro-phase separation was formed in the DQPPO-x-I membranes. The optimized DQPPO-19-OH membrane with ion exchange capacity of 2.13 meq./g exhibited the highest hydroxide conductivity of 31.6 mS/cm at 80 °C, tensile strength of 64 MPa, and thermal stability (onset decomposition temperature up to 187 °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
Polymer Chemistry
·
2023
·Vol. 14
·期 16
·1933-1944
·
IF 4.6
Yi-Fang Lu,Song-Hai Wu,Cong Wang,Yong Liu,Fu-Gen Huang,Bao-Dong Song,Xu Han
Preparing low-molecular-weight poly(2,6-dimethyl-1,4-phenylene oxide) (LMW-PPO) with high thermal stability and satisfactory dielectric properties is a challenge. Herein, we reported two methods for synthesizing LMW-PPO using metal and non-metal catalysts. In the presence of Cu(II), PPO with an Mn of 6.0 × 103 can be obtained with peroxydisulfate (PDS) as the oxidant. In the absence of Cu(II) catalysts, mesoporphyrin IX dihydrochloride or methylamine can also catalyze PDS to produce low-molecular-weight and metal-free PPO (Mn of 4.9 × 103 or 4.6 × 103). PDS not only mediates the oxidation of Cu(I) to Cu(II) with Cu(II) catalysts, which is an important step for binding phenolates to form LMW-PPO, but also abstracts H from DMP to give DMP radicals, which then polymerize to LMW-PPO in the absence of the Cu(II) catalysts. In addition, PDS can effectively break the long-chain PPO to give shorter PPO, thus effectively mediating the molecular weight of PPO. Additionally, the decrease in Tg values from 215 °C to 159 °C with decreasing Mn of PPO mediated by peroxydisulfate indicate its improved processability while maintaining high thermal stability (Td5% = 427 °C–439 °C). The satisfactory dielectric properties of the PPO obtained using PDS and metal-free catalysts also imply its high potential to be used for insulating materials.
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
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