RSC Advances
·
2016
·Vol. 6
·期 41
·34364-34375
·
IF 3.289
Jianquan Tan,Weiqu Liu,Zhengfang Wang
A series of waterborne UV-curable comb-shaped (meth)acrylate graft copolymers containing long fluorinated and/or siloxane side chains were synthesized by conventional radical copolymerization of a novel mono-methacryloyloxy terminated fluorinated macromonomer (PHFA-GMA) and/or polysiloxane macromonomer (SiOHMAC) with (meth)acrylate monomers. The separate effects of PHFA-GMA and SiOHMAC, as well as the synergic effect of these two components, on the properties, especially the surface properties were investigated in detail. A hydrophobic surface could be obtained with extremely low content of PHFA-GMA and/or SiOHMAC due to the strong tendency of the macromonomers to migrate towards the outmost layer, resulting in abundant enrichment of fluorine and silicon atoms on the surface. XPS (X-ray photoelectron spectroscopy) results revealed that for a given weight of the two macromonomers, Si atomic concentration of the copolymer modified by SiOHMAC is higher than F atomic concentration of the copolymer modified by PHFA-GMA. AFM (atomic force microscopy) images showed that surface of the copolymer modified by SiOHMAC is rougher than that modified by PHFA-GMA. Compared to PHFA-GMA, SiOHMAC had higher efficiency and effectiveness in creating hydrophobic surfaces. In addition, the influence of PHFA-GMA and/or SiOHMAC on the physical properties, such as water dispersion particle size, water absorption, pencil hardness, adhesion, mechanical properties and thermal properties were also investigated. The novel comb-shaped copolymers prepared via conventional radical polymerization not only had excellent properties but also have potential applications in large scale industrialization.
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
JOURNAL OF MOLECULAR STRUCTURE
·
2024
·
IF 4
Rui Ding,Xue-qi Zhang,Jie Liu
Polymer semiconductors with 1D and 2D side chains are prepared for photo-induced cathodic protection (PICP) of metals. Under multiple cycles of light irradiation, the 1D&2D-Side-Chain Polymer (1D&2D-SCPoly) exhibited stable PICP, generating the most negative photoinduced potential and highest cathodic protection current. It released more charge in the dark state for PICP. The performance of 1D&2D-SCPoly photoelectrode in 3.5 % NaCl solution remained superior to that of 1D-SCPoly and 2D-SCPoly exposed to a hole scavenger solution. Only the HOMO level of 1D&2D-SCPoly photoelectrode was more positive than the equilibrium potential of oxygen evolution reaction (OER), allowing for the consumption of holes via OER. The 2D side chains increased the surface roughness, featuring numerous rod-like protrusions that enhanced light absorption and created more active sites. This also induced quantum confinement effects conducive to directional electron conduction and electron-hole separation. The 2D side chains enhanced the intrachain conjugation and electron delocalization. The small π-π stacking spacing and rough surface of 1D&2D-SCPoly endow it with strong charge storage and dark-state release capabilities. The 1D&2D-SCPoly balanced intrachain and interchain electron transport and possessed a smaller bandgap, exciton binding energy and work function which improved light utilization efficiency, the probability of electron-hole separation and PICP efficiency.
研究领域:
材料科学
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电化学
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Wei Ting Gao,Xue Lang Gao,Qiu Gen Zhang,Ai Mei Zhu,Qing Lin Liu
Anion exchange membranes (AEMs) are the heart of alkaline fuel cells and water electrolysis , and have made a great progress in recent years. However, AEMs are still unable to satisfy the needs of high conductivity and stability, hindering their widespread commercialization. Side chain regulations have been widely used to prepare highly conductive and durable AEMs. Here, we construct a series of polyaromatic AEMs grafted with fluorinated cation side chains and cation-free alkyl chains with different end groups to explore the polar discrimination of side chains on membrane performance . This work demonstrates that AEMs grafting the cation side chains with superhydrophobic fluorine pendent and alkyl side chains with hydrophilic pendent enhance water content and ion conductivity. This is due to the strong immiscibility between the hydrophilic and hydrophobic head groups which promotes the establishments of microphase separation and ion highways. Specifically, poly(binaphthyl- co -terphenyl piperidinium) containing fluorinated piperidinium side chains and alkyl chains with methoxy pendent (QBNTP-QFM) possesses a satisficed OH − conductivity (170.6 mS cm −1 at 80 °C) and can tolerate 5 M hot NaOH for 2100 h with only 3.4 % conductivity loss. Expectedly, the single cell with QBNTP-QFM yields a prominent maximum power density of 1.62 W cm −2 and the water electrolysis cell with QBNTP-QFM achieves a pronounced current density of 3.0 A cm −2 at 1.8 V, both cells also display a prominent durability for 120 h operation. The results prove that this side chain optimization can improve ion conductivity and is a promising method for AEM development.
研究领域:
材料科学
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能源技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2019
·
IF 7.015
Haibing Wei,Yan Li,Sheng Wang,Guoqing Tao,Tie Wang,Sheng Cheng,Shanzhong Yang,Yunsheng Ding
Ionic-conductive polymers with highly ordered, phase-separated structure are the promising materials used as anion exchange membranes (AEMs), thanks to their pronounced ion mobility. In this study, apart from imidazolium-functionalized hydrophilic pendants, additional octyl and perfluorooctyl-containing grafts were tethered to the polymer backbone and the resultant structure-morphology relationships were systemically investigated. The results revealed that the introduction of hydrophobic side chains as well as the corresponding hydrophobicity plays an important role in the formation of a phase-separated morphology in the membrane. AEMs containing perfluorooctyl-containing pendants ( PPO- x -Im y 8F z ) exhibited a pronounced microphase-separated morphology with ion clusters of about 2–5 nm size and a spacing of ∼6 nm, while the membranes with octyl pendants ( PPO- x -Im y 8C z ) or no additional hydrophobic side chains ( PPO- x -Im ) only showed indistinct or no phase separation. In addition, PPO- x -Im y 8F z AEMs showed better ion conductivity and suppressed water absorption, thereby exhibiting a good balance between water uptake and ion conductivity. The results of this study provide an efficient strategy to guide the architectural design of high-performance AEMs.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2021
·
IF 8.198
Lv Li,Jia-ao Wang,Lingling Ma,Lei Bai,Anran Zhang,Naeem Akhtar Qaisrani,Xiaoming Yan,Fengxiang Zhang,Gaohong He
Anion exchange membranes (AEMs) usually suffer from the “trade-off” between ion conduction and stability. In this work, a series of dual-side-chain-grafted poly(phenylene oxide) AEMs were synthesized to explore how the side-chain architectures influence membrane performance. Our investigations suggest that the AEM containing both a long hydrophobic extender (attached to the cation’s central atom) and a hydrophilic additional side chain (beside the cation) show high hydroxide conductivity (21.3 mS/cm at 30 °C) and good chemical and dimensional stability (90.5% conductivity retention after 1 M NaOH treatment at 60 °C for 528 h). In addition, when a tri-cation side chain and a hydrophobic side chain are incorporated simultaneously, the resulting AEM shows further improved conductivity and stability (50.0 mS/cm at 30 °C; 90.6% conductivity retention after 1 M NaOH treatment at 60 °C for 528 h); it also shows excellent electrochemical performance when applied in a fuel cell and an electrodialyzer, accomplishing a peak power density of 506 mW/cm2 and a current efficiency of 96.11%, respectively. Our side-chain manipulation strategy provides a new and effective pathway to balance the ionic conductivity and stability of AEMs.
研究领域:
材料科学
·
电化学
·
膜技术
·
能源工程
✓ 已验证
DOI
高影响因子
COMBUSTION AND FLAME
·
2023
·
IF 4.4
Guanyu Wang,Dan Xu,Jiaqi Tang,Bingzhi Liu,Zhandong Wang,Qiang Xu,Yanjun Hu,Jinsong Zhou,Shurong Wang
As an important component of organic solid wastes, disposal of plastic wastes (PWs) has always been a thorny issue. Thermochemical conversion is an efficient method. In-depth research on the influence of structural differences on their pyrolysis behavior is beneficial to promote the development of thermal treatment and conversion technology of PWs. The differences in the chemical structure of different polyolefin plastics at the molecule level are mainly reflected in their side chains. Herein, a series of typical polyolefin plastics with similar backbone structure and different side chain structures, including high-density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyvinyl alcohol (PVA) and ethylene-vinyl acetate copolymer (EVA), were selected for comprehensive pyrolysis characterization in this work. Advanced experimental analysis methods such as in-situ DRIFT and 2D-PCIS were adopted to investigate the evolution of two weak oxygen-containing side chains during pyrolysis of PVA and EVA, respectively. Besides, typical product distribution of six samples were systematically studied by combining SVUV-PIMS and GC/MS. Spectral analysis showed that OH side chain in macromolecular structure of PVA had the weakest thermal stability, and its oxidation reaction occurred earlier than dissociation and dehydration, while the acetoxy side chain in EVA polymers could not only be directly dissociated via deacetoxylation, but also be transformed into OH side chain via deacetylation that occurred simultaneously with deacetoxylation. Further combined with SVUV-PIMS and GC/MS, the distribution characteristics of pyrolysis products of polyolefin plastics and the rules of generation and release of typical products with temperature were obtained in detail. It was found that the release of typical oxygen-containing products was earlier or slightly earlier than the release of hydrocarbons in pyrolysis of PVA or EVA. However, the release of all hydrocarbons was almost simultaneous during the respective pyrolysis process of HDPE, PP and PS, suggesting that the evolution of oxygen-containing side chains with weak thermal stability occurred earlier under the drive of temperature. Based on the characterization results, the main evolution pathways of different side chains were proposed to explain the influence mechanism of different side chain structures on the pyrolysis behavior of polyolefin plastics. The cleavage of C C bonds mainly occurred in HDPE, PP and PS, while the evolution of side chains occurred first in PVC, PVA and EVA, and exerted different influence on the degradation of carbon skeleton.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2017
·
IF 6.395
Jinchao Li,Suqin Liu,Zhen He,Zhi Zhou
A novel branched side-chain-type sulfonated polyimide (6F-s-bSPI) membrane with accessible branching agents of melamine , hydrophobic trifluoromethyl groups ( CF 3 ), and flexible sulfoalkyl pendants is prepared by a high-temperature polycondensation and post-sulfonation method for use in vanadium redox flow batteries (VRFBs). The chemical structure of the 6F-s-bSPI membrane is confirmed by ATR-FTIR and 1 H NMR spectra. The physico-chemical properties of the as-prepared 6F-s-bSPI membrane are systematically investigated and found to be strongly related to the specially designed structure. The 6F-s-bSPI membrane offers a reduced cost and possesses a significantly lowered vanadium ion permeability (1.18 × 10 −7 cm 2 min −1 ) compared to the linear SPI (2.25 × 10 −7 cm 2 min −1 ) and commercial Nafion 115 (1.36 × 10 −6 cm 2 min −1 ) membranes, prolonging the self-discharge duration of the VRFBs. In addition, the VRFB assembled with a 6F-s-bSPI membrane shows higher coulombic (98.3%–99.7%) and energy efficiencies (88.4%–66.12%) than that with a SPI or Nafion 115 membrane under current densities ranging from 20 to 100 mA cm −2 . Moreover, the VRFB with a 6F-s-bSPI membrane delivers a stable cycling performance over 100 cycles with no decline in coulombic and energy efficiencies. These results show that the branched side-chain-type structure is a promising design to prepare excellent proton conductive membranes.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2021
·
IF 6.953
Wei Tang,An-Qi Li,Jun-Yi Yin,Shao-Ping Nie
Three water-soluble pectic polysaccharides (WKBP-P2, P3 and P4) were isolated from white kidney bean by ion exchange combined with size-exclusion methods. The structural features were characterized by GC–MS, NMR spectroscopy and HPSEC-MALLS-RI. It was found that three pectic polysaccharides were the major water-extracted polysaccharides in white kidney bean. All the WKBP-P2, P3 and P4 were probably composed of various structural regions including homogalacturonan (HG), xylogalacturonan (XGA), rhamnogalacturonan I (RG-I) regions in backbone, and arabinan region mainly as side chain. However, these pectic polysaccharides were significantly different in molar ratios of these structural regions and molecular size. WKBP-P2 was HG-predominant pectin (partially methyl-esterified) with weight-average molecular weight ( M w ) of 1.2 × 10 4 g/mol, and contained minor RG-I, arabinan and probable XGA regions. WKBP-P3 ( M w of 4.0 × 10 4 g/mol) primarily embraced XGA, HG, arabinan regions and minor RG-I region. WKBP-4 with highest M w (4.5 × 10 5 g/mol) had the most arabinan region (51.3%), which was probably the side chain linked to the backbone composed of RG-I, HG and slight XGA regions. These findings provided a structural basis for study on polysaccharides from white kidney bean, which was benefit for development of functional food.
研究领域:
食品科学
·
植物化学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2015
·Vol. 53
·期 21
·2469-2480
·
IF 3.113
Yong Deng,Xi Wang,Qiulin Yuan,Mengxiang Zhu,Ying Ling,Haoyu Tang
A series of side-chain-functionalized α-helical polypeptides, i.e., poly(γ-4-(3-chloropropoxycarbonyl)benzyl- L -glutamate) (6) have been prepared from n-butylamine initiated ring-opening polymerization (ROP) of γ-4-(3-chloropropoxycarbonyl)benzyl- L -glutamic acid-based N -carboxyanhydride. Polypeptides bearing oligo-ethylene-glycol (OEG) groups or 1-butylimidazolium salts were prepared from 6 via copper-mediated [2+3] alkyne-azide 1,3-dipolar cycloaddition or nuleophilic substitution, respectively. CD and FTIR analysis revealed that the polymers adopt α-helical conformations both in solution and the solid state. Polymers bearing OEG (m = 3) side-chains showed reversible LCST-type phase transition behaviors in water while polymers bearing 1-butylimidazolium and I − counter-anions exhibited reversible UCST-type transitions in water. Variable-temperature UV-vis analysis revealed that the phase transition temperatures ( T pt s) were dependent on the main-chain length and polymeric concentration. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53 , 2469–2480
研究领域:
高分子化学
·
生物材料
✓ 已验证
产品关联
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2015
·Vol. 18
·期 5
·3884-3892
·
IF 4.493
Xinyuan Che,Shiming Gong,Heng Zhang,Bin Liu,Yinghan Wang
Polyimides (PI-N9 and PI-N12) were synthesized from two kinds of functional diamines, whose junction modes between backbones and side chains were different. Side chains of PI-N9 were linked to the backbones with an ether bond spacer; and side chains of PI-N12 were directly linked to the backbones without any spacer. The PI alignment layer surfaces were investigated by atomic force microscopy, surface free energy measurements, X-ray photo-electron spectroscopy and polarized attenuated total reflection Fourier transformed infrared spectroscopy. It was found that PI-N9 lost the vertical alignment capability after high-strength rubbing, while PI-N12 could still induce liquid crystals (LCs) to align vertically under the same condition. The mechanism of the macroscopic molecular orientation of the PI surface is proposed. During the high-strength rubbing process, the side chain could rotate around the flexible ether bond which existed between the side chain and the main chain of PI-N9 and then fell over. Therefore, PI-N9 could not induce the vertical alignment of LCs anymore. But PI-N12 could keep LCs aligning vertically all the time, which proved that the stability of LC alignment induced by PI-N12 was better.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2023
·
IF 7.4
Chengda Li,Yueli Wen,Bin Wang,Maohong Fan,Wenlong Liu,Zheng Cui,Wei Huang
Activation and desorption of the hydrogen atom in the toluene methyl is a restrictive step for side-chain alkylation of toluene with methanol (SATM). In this work, two dehydrogenation strategies were used to improve the catalytic performance, dehydrogenation component Cu was introduced in PAl-NaX catalyst as well as the acid-base property was adjusted by changing NaOH loading amount. The relationship among the percentage of acid-base sites, low valence Cu species and the catalytic performances was investigated combined with the multiple characterizations, like X-ray photoelectron spectroscopy (XPS), Temperature-programmed desorption (TPD) of NH 3 and CO 2 , etc. together with ternary regression analysis. It is found that the dehydrogenation component Cu, especially low valence Cu species, promotes the selectivity of side-chain alkylation products to a certain degree, but base sites play an even more critical role in enhancing it.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Polymer Chemistry
·
2014
·Vol. 5
·期 13
·4105-4114
·
IF 5.368
Xi Chen,Nan Zheng,Qiao Wang,Lingzhi Liu,Yongfeng Men
The influence of different synthetic pathways on the phase transition and side-chain crystallization behavior of cellulose ethers was systematically investigated by a combination of differential scanning calorimetry (DSC), small and wide-angle X-ray scattering (SAXS, WAXS) and Fourier transform infrared spectroscopy (FTIR) techniques. DSC investigation indicated that the melting temperature and crystallization temperature, respectively, of cellulose derivatives that were synthesized by homogeneous reactions in cellulose solutions differed from those of cellulose aggregates in a swollen state synthesized by heterogeneous reactions; this implies that the synthetic pathway had a strong effect on the side-chain crystallization behavior in comb-like polymers. WAXS results showed that the cellulose ethers prepared by homogeneous reaction packed into hexagonal crystals, while those prepared by heterogeneous reaction exhibited multiple crystals. These phenomena may be understood as a result of the effect of the regularity of the main chain and the difference in hydrogen bonding interactions in the two kinds of cellulose ethers. For the latter, the presence of free –OH groups at the C-6 position in the samples obtained via the heterogeneous reaction is considered to contribute critically to intermolecular hydrogen bonds that promote crystallization of the system.
研究领域:
材料科学
·
聚合物化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）