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
·
材料科学
✓ 已验证
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
✓ 已验证
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
·
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
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 140
·期 10
·e53579
·
IF 3.057
Rui Liu,Yiwen Nie,Junjie Chen,Chunhui Shen,Shanjun Gao
Poly (styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) has been widely studied in the field of anion exchange membranes (AEMs) due to its superior flexibility and chemical stability, but the poor dimensional stability of functionalized SEBS restricts its further application. Thus, we adopt an effective strategy to reinforce AEMs based on SEBS via grafting poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) using Williamson ether synthesis reaction. With the addition of PPO, grafted membranes exhibit outstanding comprehensive properties, such as mechanical strength, chemical stability, especially dimensional stability. SEBS-PPO-QA-1 grafted membrane with the highest content of PPO showed the best tensile strength (20.54 MPa), and restrained swelling behavior (swelling ratio of 4.81% at 25°C). Moreover, the conductivity retention of SEBS-PPO-QA-1 grafted membrane is up to 92.71% at 80°C after 10 days alkaline treatment. The ion exchange capacity of SEBS-PPO-QA-3 grafted membrane is 1.719 mmol/g, and the ionic conductivity of SEBS-PPO-QA-3 grafted membrane reach 58.27 mS/cm at 80°C and 25.53 mS/cm at 20°C. Therefore, the SEBS-PPO-QA- X grafted membranes, which combine the advantages of PPO and SEBS, are promising in AEM application.
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
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2021
·
IF 5.816
Qian Liu,Zhe Wang,Aijun Yu,Jinsheng Li,Hongcheng Shen,Hui Wang,Kai Yang,Hongyu Zhang
We report a novel comb-shaped anion exchange membrane based on poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) and 4-(dimethylamino)butyraldehyde diethyl acetal (DABDA). The Menshutkin reaction successfully introduced DABDA into the brominated PPO backbone, which was proved through FT-IR and 1 H NMR. The distinct hydrophilic/hydrophobic microphase separation structure observed by transmission electron microscope (TEM). As the increase of grafting degree, so does the water uptake, swelling ratio, hydroxide conductivity and alkaline stability. The membranes also possess good mechanical property with tensile strength from 14.2 to 38.11 MPa. This is due to the increasing number of hydroxide and unique steric hindrance effect caused the higher water uptake and higher dimensional stability. Simultaneously, especially PPO/DABDA-60 in comb-shaped membranes demonstrate an excellent long-term alkali resistance stability. In a 576-h alkali resistance stability test, the retained ionic conductivity of the PPO/DABDA-60 membrane is 96% of the initial value. The PPO/DABDA-60 is a potential candidate material for AEM.
研究领域:
材料科学
·
化学工程
·
电化学
✓ 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）