查找使用阿拉丁产品的科研文献

Preparation and properties of 4, 4′-diphenylmethane diisocyanate blocking modified poly(propylene carbonate)

Sujuan Pang,Nai Xu,Guang Xu,Lisha Pan,Qiang Lin,Xin Wang

Poly(propylene carbonate) (PPC) is inferior in thermal stability and liable to incur thermal degradation, especially in the existence of residual bimetal catalyst. In this article, PPC containing residual catalyst was end-capped with 4, 4′-diphenylmethane diisocyanate (MDI) through melt compounding. The blends were characterized by infrared spectra, melt flow index (MFI), gel permeation chromatography (GPC), gel content measurement, thermogravimetric analysis, scanning electron microscopy, and tensile test. The effect of MDI on thermal stability, molecular weight, and tensile properties of PPC was studied. Thermal degradation kinetics of neat PPC and PPC+MDI blending samples was discussed with Friedman method. MFI, GPC, and gel content measurements showed that mainly end-capping reaction was carried out on PPC chains when 0.1% of MDI was added. However, as the amount of MDI exceeded to 0.3%, end-capping, chain-extension, and crosslinking reactions were synchronously carried out on PPC. Results showed that the end-capping, chain-extension, and crosslinking reaction occurring between PPC and MDI could effectively inhibit the unzipping degradation even when the residual catalyst was not removed thoroughly. When the content of MDI reached 1.0%, the initial degradation temperatures ( T - 5% ) increased from 176.26°C for neat PPC to 259.56°C. As a result, the processing temperature range and processing time were largely extended, and the heat resistance of PPC was improved remarkably. Meanwhile, the tensile property of the modified PPC was enhanced obviously. It may be due to the fact that the molecular weight and gel content of PPC were increased with the increasing amount of MDI. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

A simplified and facile preparation method for the [Ca24Al28O64]4+(e−)4 electride

Xiangyu Zhang,Yunlei Chen,Yongfang Sun,Fei Wang,Xiao-Dong Wen,Tian-Nan Ye

Wide application of novel materials often requires low-cost preparation methods. In this study, we present a simplified and facile preparation method for the [Ca24Al28O64]4+(e−)4 electride material (C12A7:e−). Successful preparation of the C12A7:e− electride was confirmed by XRD patterns and magnetic behavior analysis. The concentration of electrons in the prepared C12A7:e− powder was calculated to be approximately 2.23 × 1021 cm−3, as evaluated by iodometry and TPD. DFT calculations provided insight into the unique electronic structure of C12A7:e−. Additionally, the substitution of the Ca reductant with CaH2 led to a reduction in the solid-state reaction temperature from 1100 to 950 °C, which can be attributed to thermodynamic effects such as a reduction in ΔG°.

Study of 4, 4′-methylenebis-cyclohexanamine as a high temperature-resistant shale inhibitor

Zhong Hanyi,Qiu Zhengsong,Tang Zhichuan,Zhang Xin,Xu Jiangen,Huang Weian

In order to develop high-performance water-based drilling fluid with the aim of meeting the increasing requirement of drilling industry, highly inhibitive and high-temperature-resistant shale inhibitors are essential. In this study, 4, 4′-methylenebis-cyclohexanamine was introduced as a potential shale inhibitor. The inhibitive properties of the amine compound in comparison with currently available polyether diamine inhibitor were evaluated using bentonite inhibition test, shale cuttings hot-rolling dispersion test, linear swelling test, and pressure transmission test. The inhibitive mechanism was investigated with zeta potential measurement, X-ray diffraction analysis, and contact angle measurement. The results indicated that 4, 4′-methylenebis-cyclohexanamine can inhibit shale hydration and dispersion effectively, and prevent pressure transmission to a certain extent, performing better than that of polyether diamine. Furthermore, the new diamine provides reliable thermal stability as high as 220 °C, preserving the benefits of high-temperature wells application. This novel diamine inhibits shale hydration and dispersion with the combination of chemical inhibition and physical plugging. The intercalation into the interlayer of clay with monolayer collapses the hydrated clay structure and expels the water molecules. After adsorption, clay surface became more hydrophobic, which prevents the imbibition of water. The variation of solubility separates the compound from the solution, which can plug the micro-pores of shale and prevent fluid invasion.

Synthesis and comparative study on polyetherimides from isomeric 4,4′-isopropylidenediphenoxy bis(phthalic anhydride)s

Hongyu Jiang,Hanzhou Jiang,Guofei Chen,Xingzhong Fang

Two isomers of commercial 4,4′-(4,4′-isopropylidenediphenoxy) bis(phthalic anhydride) (4,4′-BPADA), that is, 3,4′-(4,4′-isopropylidenediphenoxy) bis(phthalic anhydride) (3,4′-BPADA) and 3,3′-(4,4′-isopropylidenediphenoxy) bis(phthalic anhydride) (3,3′-BPADA), were synthesized through aromatic nucleophilic substitution from nitrophthalonitrile and bisphenol A. 3,4′-BPADA was first synthesized from two intermediates, that is, 3-(4-[4-hydroxyphenylisopropylidene] phenoxy) phthalonitrile (3-BPADN) and 3,4′-(4,4′-isopropylidenediphenoxy) bis(phthalonitrile) (3,4′-BPATN). The corresponding three series of polyetherimides (PEIs) were prepared with two representative aromatic diamines (4,4′-oxydianiline and m -phenylenediamine ( m -PDA)) via two-step procedure and chemical imidization. Isomeric polyimides showed T g s from 206 to 256°C in nitrogen and T d5% s from 488 to 511°C in argon, good mechanical properties (tensile moduli of 2.3–3.3 GPa, tensile strengths of 70–96 MPa, and elongations at break of 3.2%–5.1%), and good solubility. With the introduction of 3-substituted phthalimide unit, PEIs displayed higher T g values, lower strengths and elongations, better solubility and larger d -spacings. The rheological properties of thermoplastic polyimide resins based on the BPADA isomers were investigated, which showed that polyetherimide PEI-3b derived from 3,3′-BPADA and m -PDA had the lowest melt viscosity among the isomers, indicating that the melt processibility had been greatly improved. Graphical

Design, Synthesis, Structure–Activity Relationship, Molecular Docking, and Herbicidal Evaluation of 2-Cinnamoyl-3-Hydroxycyclohex-2-en-1-one Derivatives as Novel 4-Hydroxyphenylpyruvate Dioxygenase Inhibitors

Hao-Min Song,Li-Xia Zhao,Shuai-Qi Zhang,Tong Ye,Ying Fu,Fei Ye

Cinnamic acid, isolated from cinnamon bark, is a natural product with excellent bioactivity, and it effectively binds with cyclohexanedione to form novel 4-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitors. According to the active sub-structure combination principle, a series of novel 3-hydroxy-2-cinnamoyl-2-en-1-one derivatives were designed and synthesized. The title compounds were characterized by infrared, 1H NMR, 13C NMR, and HRMS. The in vitro inhibitory activity of AtHPPD verified that compound II-13 showed the most activity with a half-maximal inhibitory concentration (IC50) value of 0.180 μM, which was superior to that of mesotrione (0.206 μM) in vitro. The preliminary herbicidal activity tests demonstrated that some compounds had good herbicidal activity especially compound II-13 at a concentration of 150 g ai/ha. The binding mode of AtHPPD through molecular docking indicated that two oxygens of compounds II-13 formed bidentate interactions with metal ions, and the benzene ring formed π-π accumulation effects with Phe-381 and Phe-424. The results of molecular dynamics simulations showed that compound II-13 exhibited a more stable binding ability with AtHPPD than mesotrione. This study provided insights into the development of natural and efficient herbicides in the future.

Solubility and liquid crystal vertical alignment of polyimides derived from a new diamine: 4-((4-dodecyloxy)phenyl)-2,6-di((4-amino)phenyl)pyridine

Lu-Lu Liu,Xin-Guo Zheng,Zhen Sun,Ying-Han Wang

K2Pb(H2C3N3O3)4(H2O)4: a potential UV nonlinear optical material with large birefringence

Yan Chen,Chunli Hu,Zhi Fang,Jianggao Mao

Cyanurate motifs are emerging functional basic blocks (FBBs) for nonlinear optical (NLO) materials and birefringent materials. Herein, we report two new potassium lead(II) hydroisocyanurates, namely, K2Pb(H2C3N3O3)4(H2O)4 (I) and K3Pb(H2C3N3O3)5(H2O)6 (II). I and II belong to acentric Cm and centric C2/m, respectively. Compound I features a novel 3D network formed by 2D [K2PbO8(H2O)4]12− anionic layers interconnected by (H2C3N3O3)− anions. The 2D [K2PbO8(H2O)4]12− anionic layer is composed of 1D chains of edge-sharing K(1)O6 and K(2)O8 being further interconnected by 8-coordinated Pb2+ ions. Compound II exhibits a characteristic 3D framework based on 2D [K3PbO11(H2O)6]17− anionic layers interlinked through (H2C3N3O3)− groups, and the 2D [K3PbO11(H2O)6]17− anionic layer is based on K–O/H2O chains bridged by Pb2+ ions. Powder second harmonic generation (SHG) measurements of I revealed a moderate SHG response of approximately 2.6 × KDP with a type I phase-matching behavior under 1064 nm laser radiation. Theoretical calculations of I and II revealed their birefringence to be 0.325 and 0.193@532 nm, respectively. Their impressive optical properties mainly stem from stereochemically active lone pair (SCALP) Pb2+ cations and the planar π-conjugated (H2C3N3O3)− groups.

Mechanical, Dielectric, and Thermal Attributes of Polyimides Stemmed Out of 4, 4’–Diaminodiphenyl Ether

Panpan Zhang,Ke Zhang,Shuliang Dou,Jiupeng Zhao,Xiangqiao Yan,Yao Li

Several kinds of polyimide (PI) films stemmed out of 4, 4’–diaminodiphenyl ether, as well as various structurally various aromatic dianhydride, were prepared. The films’ mechanical, dielectric, and dynamic mechanical attributes were put under investigation. According the findings, the PI films’ performance is significantly different as a result of their diverse structure. PI’s dielectric constant and dielectric loss tangent of abides by the increasing order below: PMDA-PI>BTDA-PI>BPDA-PI. Moreover, the electric breakdown strength of BTDA-PI (478.90 kV/mm) presents a lot higher value compared to the one PMDA-PI (326.80 kV/mm) and BPDA-PI (357.07 kV/mm). In particular, BTDA-PI film possesses high electric breakdown strength about 478.90 kV/mm. In addition, PI’s glass transition temperature (Tg) are, respectively, 276 °C (BTDA-PI), and 290 °C (BPDA-PI), as well as 302 °C (PMDA-PI). Therefore, in virtue of their various structures and performances, practical applications of PI films can exert significant role in the electronics and microelectronics industries.Keywords:polyimide;film;dielectric properties;thermal properties

Polyimides from 2,5-bis[4-(4-aminophenoxy)benzoyl]furan and their thermal crosslinking reaction

Kai Ma,Hanzhou Jiang,Guofei Chen,Wei Wang,Yonggang Zhang

Several polyimides were prepared via two-step polycondensation from novel 2,5-furandicarboxylic acid–based diamine, 2,5-bis[4-(4-aminophenoxy)benzoyl]furan, with commercial dianhydrides. The chemical structures of the monomers and polymers were characterized by FT-IR and NMR in detail, respectively. The polyimides exhibited high performances with 5 wt% weight loss temperatures of over 410 oC, glass transition temperatures of over 214 oC, and tensile strengths and Young’s moduli of up to 130 MPa and 3.2 GPa, respectively. The thermal crosslinking mechanism was studied by FT-IR, Raman spectroscopy, and model reaction analysis, which showed the Diels–Alder reaction between the furan group and diphenylethylene group was the main reaction. The crosslinked polyimide films showed improved solvent resistance, and thermal and mechanical properties.

Structural variability, topology and luminescent properties of three new cadmium (II) coordination polymers based on 4′,4′,4′-[(trimethylamino)]-tris[(1,1′-biphenyl)-2-carboxylate]

Meiyu Xu,Guangming Liang,Shuang Wang,Xueli Ma,Guangyuan Liang,Qingling Ni

The semi-rigid polycarboxylic acid, 4′,4′,4′-[(trimethylamino)]-tris[(1,1′-biphenyl)-2-car- boxylic acid] (H 3 TMCA), is first synthesized and used to self-assembly three cadmium coordination polymers , formulated as {[Cd(HTMCA)]•(H 2 O)•(DMA)} n (1), {[Cd(HTMCA)(H 2 O)]·(H 2 O) 5 } n (2), {[Cd(TMCA)] - (CH 3 CH 3 NH 2 ) + •H 2 O} n (3) by the reaction of Cd(NO 3 ) 2 ·4H 2 O under solvothermal conditions. The coordination polymers have been characterized by elemental analysis , IR spectroscopy , thermogravimetric analysis and single-crystal X-ray diffraction. Complex 1 is a 2D framework with a point symbol of {6˄3}. Complex 2 exhibit a 3D topology net with point symbol of {10˄3}. Complex 3 display a (3,6)-connected 3D topology net with point symbol of {4.6 2 } 2 {4 2 .6 10 .8 3 }. The structural comparison of complexes 1–3 shows that the final frameworks can be adjusted by changes in the reaction of temperature and solvents. Moreover, the solid-state photoluminescence properties of 1 – 3 have also been investigated.

The remarkable structural comparison between two-dimensional and three-dimensional of 4, 4′-trimethylenedipyridine/1, 3, 5-trifluoro-2, 4, 6-triiodobenzene co-crystal

Jian He,Aisen Li,Yanchun Tao,Ning Chu,Zhixiang Wang,Shuping Xu,Jing Wang,Houyu Zhang,Jingsheng Yu,Weiqing Xu

A two-dimensional (2D) co-crystal composed of 1, 3, 5-trifluoro-2, 4, 6-triiodobenzene and 4, 4′-trimethylenedipyridine via halogen bonding (I···N) was obtained on highly-oriented pyrolytic graphite , and was characterized by scanning tunnelling microscope supplemented by the density functional theory calculation. Its special structure at the interface was further compared with its three-dimensional (3D) co-crystal structure. No orderly structures were observed when Au (111) was applied. The 2D co-crystal grown on the interface is significantly different from the 3D co-crystal. This study is of vital significance in understanding the growth mechanisms of 2D functional co-crystals.

Simultaneous detection of 4-chlorophenol and 4-nitrophenol using a Ti3C2Tx MXene based electrochemical sensor

Ling Lei,Caoling Li,Wensheng Huang,Kangbing Wu

Developing a sensitive and rapid detection method for 4-chlorophenol (4-CP) and 4-nitrophenol (4-NP) is very important due to their high toxicity. In this work, bulk Ti3AlC2 powder was etched to Ti3C2Tx for the first time through a hydrothermal reaction in NaF/HCl solution. After ultrasonication in N-methylpyrrolidone (NMP), Ti3C2Tx powder was successfully exfoliated into multilayered Ti3C2Tx nanosheets (i.e. Ti3C2Tx MXene). The prepared Ti3C2Tx MXene not only has a large electrochemical surface area for the oxidation of 4-CP and 4-NP, but also lowers their electron transfer resistance. As a result, the oxidation signals of 4-CP and 4-NP are significantly improved on the surface of the Ti3C2Tx MXene. Based on the remarkable signal amplification of the Ti3C2Tx MXene, a sensitive and rapid method was developed for the simultaneous detection of 4-CP and 4-NP. The linear range is from 0.1 to 20.0 μM for 4-CP, and from 0.5 to 25.0 μM for 4-NP, with detection limits of 0.062 μM (4-CP) and 0.11 μM (4-NP). This method was used in wastewater samples, and the accuracy was confirmed to be good by high-performance liquid chromatography.