JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2010
·Vol. 48
·期 24
·5643-5651
·
IF 3.971
Peng-Fei Gou,Wei-Pu Zhu,Zhi-Quan Shen
Novel calixarene-centered amphiphilic A 2 B 2 miktoarm star copolymers composed of two PCL arms and two PEG arms with calix[4]arene as core moiety were synthesized by the combination of CROP and “click” chemistry. First, a heterotetrafunctional calix[4]arene derivative with two hydroxyl groups and two alkyne groups was designed as a macroinitiator to prepare calixarene-centered PCL homopolymers (C4-PCL) by CROP in the presence of Sn(Oct) 2 as catalyst at 110 °C. Next, azide-terminated PEG (A-PEG) was synthesized by tandem treating methoxy poly(ethylene glycol)s (mPEG) with 4-chlorobutyryl chloride and NaN 3 . Finally, copper(I)-catalyzed cycloaddition reaction between C4-PCL and A-PEG led to A 2 B 2 miktoarm star copolymer [C4S(PCL) 2 -(PEG) 2 ]. 1 H NMR, FT-IR, and SEC analyses confirmed the well-defined miktoarm star architecture. These amphiphilic miktoarm star copolymers could self-assemble into multimorphological aggregates in water. The calix[4]arene moieties with a cavity <1 nm on the hydrophilic/hydrophobic interface of these aggregates may provide potential opportunities to entrap guest molecules for special applications in supermolecular science. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
研究领域:
高分子化学
·
超分子科学
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DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL PHYSICS
·
2020
·Vol. 33
·期 1
·69-74
·
IF 1.067
Chen Zhuang,Liu Yang-yi,He Xiao-xiao,Chen Jin-quan
As one of the biological endogenous pigments, biliverdin (BV) and its dimethyl
ester (BVE) have extremely weak fluorescence in solution with quantum yield less
than 0.01%. However, the situation reverses with the addition of zinc ions. The
strength for fluorescence of BVE-Zn 2+ complex is greatly enhanced and
fluorescence quantum yield can increase to 5%. Herein, we studied ultrafast
excited state dynamics of BVE-Zn 2+ complex in ethanol, n -propanol, and DMSO solutions in order to reveal the
mechanism of fluorescence quantum yield enhancement. The results show that BVE
can form a stable coordination complex with zinc with 1:1 stoichiometry in
solution. BVE is structurally and energetically more stable in the complex.
Using picosecond time-resolve fluorescence and femtosecond transient absorption
spectroscopy, we show that smaller non-radiative rate constant of
BVE-Zn 2+ complex in DMSO is the key to increasing its
fluorescence quantum yield and the excited state decay mechanism is also
revealed. These results provide valuable information about the fluorescence
property change after BVE binding to metal ions and may provide a guidance for
the study of phytochromes or other fluorescence proteins in which BV/BVE acts as
chromophores.
研究领域:
生物化学
·
光生物学
✓ 已验证
DOI
高影响因子
POLYMER INTERNATIONAL
·
2020
·Vol. 69
·期 9
·876-882
·
IF 2.574
Shaobin Xu,Dekun Sheng,Yan Zhou,Haohao Wu,Haopu Xie,Xiangdong Liu,Yuming Yang
Most self-healing materials based on noncovalent bonding suffer from poor mechanical performance, which largely limits their further application. Herein, we designed and synthesized robust and healable polymers that can be healed under heating. They consist of a linear and three-arm branched polyurethane mixture with triazole ligand end groups that are noncovalently linked through Fe–triazole interaction. The three-arm branched polyurethane in the polymer mixture would imply parts of Fe-triazole coordination bonds were replaced by covalent bonds and, as a consequence, yield materials with improved mechanical properties. Additionally, the mechanical properties of resulting polymers can be tuned by the number of Fe–triazole supramolecular crosslinks. Due to the dynamic nature of Fe–triazole interaction, all the metallopolymers exhibit excellent healable efficiency (over 90%) based on toughness. © 2020 Society of Chemical Industry
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 35
·e52824
·
IF 3.057
Chengbing Gong,Bihua Xiao,Xianhai Hu,Yuxi Xian,Ping Wang,Yuqing Yang,Xiang Luo,Mingjun Li,Jin Liu,Yunsheng Ding,Pei Xu,Chao Liu
An amino-hydroxy-functionalized strongly fluorescent hybrid silicon quantum dots (znoSiQDs) were prepared by a green and simple method. Waterborne polyurethane-based hybrid fluorescent silicon Quantum dots (znoSiQDs-WPU) was prepared by a modified acetone method using znoSiQDs as chain extender. The structure and properties were also investigated by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analyzer (TGA), fluorescence spectroscopy (FL), and so on. ZnoSiQDs was successfully connected to the polyurethane backbone by covalent bonding. ZnoSiQDs-WPU can effectively shield UV in the range of 300–400 nm. Compared with WPU, the UV shielding range of znoSiQDs-WPU is significantly larger, attributed to the direct band gap transition Γ → Γ. The fluorescence intensity of znoSiQDs-WPU was dramatically enhanced compared with that of znoSiQDs. Compared with znoSiQDs, the maximum emission peak of znoSiQDs-WPU is blue shifted at about 18 nm, which was related to the increased polarity of the imidazole chromophore. The luminous life of znoSiQDs-WPU is up to 6.58 ns. The thermal stability of znoSiQDs-WPU is improved by bonding znoSiQDs to the main chains of WPU. Furthermore, it is water as a solvent, especially suitable for safety, green, environment amity of materials.
研究领域:
材料科学
·
化学工程
✓ 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
FUEL
·
2022
·
IF 8.035
Yuncong Li,Songdang Zhang,Zao Li,Heng Zhang,Hu Li,Song Yang
Biodiesel is being deemed a kind of important renewable energy source and also shows the great potential to replace fossil fuels to respond to global primary energy demands. However, by-product water generated during the esterification reaction of biodiesel production is not conducive to the forward progress of the reaction, and even affects the pristine structure and activity of the employed catalytic material. In this work, the hydrophobic polymeric bio-based solid acid catalyst FDCA/SA-UiO-66(Zr) was prepared by a facile grinding method using biomass-derived stearic acid (SA) and 2,5-furandicarboxylicacid (FDCA) as hydrophobic ligand and green organic linker, respectively. Accordingly, the corresponding characterization results showed that the relevant material had a good particle shape along with a highly hydrophobic network (136.4°), wherein the significant hydrophobic environment was determined to promote the adsorption of lipophilic acid and the desorption of water on the Lewis acid site. Compared with traditional heterogeneous and homogeneous acid catalysts, just at a low temperature (60.2 °C, 98.4% yield), FDCA/SA-UiO-66(Zr) exhibited superior or equivalent catalytic performance in the esterification of FFAs for biodiesel manufacture. More importantly, thanks to the stable skeleton structure of UiO-66(Zr), the catalyst demonstrated a stable structure and good reusability during 6 consecutive recycles (92.5% biodiesel yield).
研究领域:
化学工程
·
可再生能源
·
催化材料
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2018
·
IF 4.427
Ting Tang,Guining Lu,Wenjing Wang,Rui Wang,Kaibo Huang,Zhiyuan Qiu,Xueqin Tao,Zhi Dang
In this study, the TiO 2 -mediated photocatalytic removal of organic phosphate esters (OPEs) under UV irradiation was investigated. In addition, the effects of selected inorganic ions and humic acid (HA) were examined. TCEP, TCPP, and TDCPP hardly undergo degradation via photolysis, and TiO 2 -mediated photocatalysis was confirmed to be effective for removing OPEs present in a water matrix. Inorganic ions (e.g., PO 4 3− , SO 4 2− , Cl − , and NO 3 − ) and HA inhibited the degradation of OPEs. Among these selected ions, PO 4 3− exhibited the strongest inhibition ability, followed by SO 4 2− and then Cl − and NO 3 − , and the inhibition effect increased with the ion concentration . The inhibition effect was caused by two main reasons: (1) Inorganic ions or HA served as ·OH scavengers and competed with OPEs for ·OH. (2) On account of the adsorption of inorganic ions and HA on TiO 2 , the available surface-active sites for OPEs decreased, followed by their oxidation with surface-bound ·OH. The ·OH concentrations were measured by electron spin resonance and the probe method, and it was positively correlated to the degradation rate of OPEs. This study emphasized the importance of inorganic species and HA on the photocatalytic degradation of OPEs and clarified the inhibition mechanism for the degradation of OPEs by the inorganic species or HA.
研究领域:
环境科学
·
化学
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2023
·Vol. 31
·期 1
·1-14
·
IF 2.8
Song T.,Ren L.,Li W. B.,Liu Q.,Qin Y. X.,Zhang Y. L.,Wang Y. B.,Shen Y. D.,Du W. N.,Zhang M. Y.
In this contribution, isosorbide dinonanoate (SDN), an environmentally sustainable plasticizer for polypropylene (PP), is successfully synthesized by virtue of esterification reaction using isosorbide and nonanoic acid with the reaction temperature of 120 °C, and the reaction time of 5 h. When the corporation of plasticizer SDN into PP matrix is the value of 15 phr, the impact strength of PP blends reaches 121 J/m, the dramatically increase of 384% compare to that of PP. DMA results shows that the glass transition temperature (T g ) of PP blends gradually decline with the increasing amount of SDN, indicating the efficient plasticization action of the SDN. It is suggested that SDN can be feasibly inserted into the non-polar matrix and then more evenly dispersed in matrix, herein, it will increase the distance between the polymer chains, improving the mobility of the molecular chains and the processing performance of the polymers. Furthermore, the plasticizing effect and environmental friendliness of SDN can be a potential replacement for o-phenyl plasticizers in the industry in the future.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
MACROMOLECULAR RESEARCH
·
2018
·Vol. 26
·期 4
·365-373
·
IF 1.767
Ling Lei,Li Jinhui,Zhang Guoping,Sun Rong,Wong Ching-Ping
Self-healing polymeric materials have attracted extensively interests due to the ability to heal the damage autonomously. The self-healing systems based on dynamic disulfide bonds have been the most promising due to the efficient healing capacity at a mild condition. However, it is still of great challenge for designing the polymer with excellent mechanical and self-healing property by a simple synthetic route. Herein, a novel series of self-healing linear polyurethanes with the disulfide linkage as the grafting point were developed. The synthetic polymers all exhibited excellent mechanical properties (breaking strength and elongation at break were as much as 31.91 MPa and 1156% for PU-A). Meanwhile, the effects of different ratios of soft/hard segments on the mechanical properties and healing efficiencies have been investigated by stress-strain tests. The results showed that with the increase of soft segments contents, the breaking strength and elongation at break of the polymer improved significantly, while the healing efficiency and Young’s modulus showed a declining trend. The self-healing polyurethane can quickly restore its over 90% of mechanical property after healing at moderate temperature for 10 min. The cyclic tensile tests also showed the dissipated efficiencies and self-recovery abilities of the polymers. Finally, the recovery capability tests verified the shape memory effect in the polymers, which can replace an external force to accelerate the healing process.
研究领域:
材料科学
·
高分子化学
✓ 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
JOURNAL OF MATERIALS IN CIVIL ENGINEERING
·
2023
·Vol. 36
·期 3
·04023627
·
IF 3.2
Zengheng Hao,Bailin Shan,Pan Liu,Yan Wu,Xuejuan Cao
Asphalt pavement will crack under the action of traffic load and harsh environment, and the cracks can be repaired by the self-healing properties of asphalt itself, but the healing efficiency is lower. This study developed a novel self-healing asphalt based on disulfide-crosslinked polyurethane elastomer. A low-cost crosslinking agent (CY-OA) was synthesized from cystamine dihydrochloride as raw material, and then a disulfide-crosslinked polyurethane prepolymer (PU-SS) was synthesized using a stepwise copolymerization method for modification of asphalt to obtain a self-healing polyurethane-modified asphalt. The chemical properties, microscopic morphology, and self-healing capability of disulfide-crosslinked polyurethane elastomer and polyurethane-modified asphalt were evaluated in this study. Infrared spectroscopy confirms the introduction of CY-OA into the polyurethane main chain. Thermal gravimetric analysis shows excellent thermal stability of PU-SS. Healing tests demonstrate that disulfide bonds enhance the self-healing ability between polyurethane elastomer and asphalt binder. PU-SS exhibits a healing efficiency as high as 96.33% within 12 h at 60°C. With an increase in PU-SS content and repair time in the modified asphalt, the repair efficiency increases, with a maximum fatigue recovery index of 80%. The objective of this study is to introduce dynamic covalent bonds to enhance the self-healing performance of asphalt and improve the long-term crack resistance of asphalt pavement.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 21
·52224
·
IF 3.057
Chuangchuang Sun,Wei Zhang,Yihua Cui,Dongyue Liu
A phosphazene-triazine bi-base sulfonate compound (CPNS) was synthesized using hexachlorocyclotriphosphazene, cyanuric chloride, and sodium p-hydroxybenzene sulfonate as raw materials. The chemical structure was determined by FTIR, 1 H NMR 31 P NMR (NMR stands for nuclear magnetic resonance), and elemental analysis of P, Na. To study the flame retardant properties of CPNS, a series of modified polycarbonate (MPC) with different ratios of CPNS were prepared. The flame retardant performance and thermal stability of CPNS/MPC were characterized by limiting oxygen index (LOI), UL-94 vertical burning test, cone calorimetry test, and TG. Results show that when CPNS is added to 0.3%, the CPNS/MPC can pass the UL94 V-0 level with an LOI value of 35.3% and reduce the peak heat release rate by 16.89% during the combustion. TG results show that adding 0.1% CPNS can decrease the initial decomposition temperature of the MPC by 68°C in nitrogen and 27°C in air. The reduction of the initial decomposition temperature means that the flame retardant promotes the isomerization reaction of polycarbonate accelerates the formation of an intermediate char on the surface. Investigation of intermediate char residue's morphology and chemical structure demonstrates that CPNS promotes the formation of more complete and compact char residue, which acts not only there is increased opportunity for radical recombination reactions in the condensed phase but also as physical barriers to inhibit the transfer of heat and oxygen, resulting in good flame retardant properties.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）