CHEMICAL ENGINEERING SCIENCE
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2024
·
IF 4.1
Ying Gao,Yong Liu,Lingling Gao,Jinxing Long
An effective strategy is proposed here for transfer hydrogenation of alkyl levulinate to γ-valerolactone (GVL) using a UiO-66 framework modified with phosphotungstate ionic liquid (UiO-66@IL(HPW)). Due to the intensive influence of ionic liquid fragment, the modification significantly enhances the catalytic activity of UiO-66@IL(HPW), leading to a complete conversion of ethyl levulinate with over 93.1% selectivity for GVL. Characterizations techniques, including XRD, N 2 absorption/desorption, SEM, FT-IR, pyridine FT-IR, NH 3 -TPD and CO 2 -TPD, confirm that while the basic structure of UiO-66-NH 2 is insignificantly changed, the introduction of the ionic liquid greatly improves the acidic/base properties of the catalyst. XAFS and XPS results reveal an intensive interaction between the N and W species in UiO-66@IL(HPW), and the formed W-N/O moiety is responsible for the enhanced catalytic activity. In addition, a plausible catalytic mechanism is proposed based upon in situ DRIFTS and density functional theory (DFT) calculations, highlighting the crucial role of ionic liquid fraction within the UiO-66 ligand. Therefore, this work would contribute to the valorization of biochemicals.
研究领域:
化学工程
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材料科学
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产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
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2024
·
IF 5.3
Zongpeng Liu,Shaojian Hu,Yuning Zhang,Bencheng Wu,Jianhua Zhu
Synthetic esters are expected to have broad application prospects in the high-end lubrication sectors owing to their fascinating custom-tailored properties. Herein, we synthesized a novel complex polyolester (CPE) via a stepwise esterification procedure using stannous oxide as a heterogeneous catalyst. Response surface methodology coupled with the Box–Behnken design (BBD-RSM) was employed to optimize the experimental parameters and elucidate the interactions among the operating variables on the low-temperature fluidity of CPE. The optimization results indicated that the lowest pour point (−42 °C) could be obtained under the catalyst dosage of 1.2 wt%, the first step reaction temperature of 164 °C, the first step reaction time of 100 min, and the second step reaction temperature of 178 °C. Particularly, there is a significant interactive effect between the catalyst dosage and the second step reaction temperature. Followed by the molecular distillation of the crude ester prepared under the optimal conditions, the refining results revealed that the non-ideal components had been effectively removed and the total acid number of the final product was substantially reduced to below 0.1 mg KOH/g. The molecular structures of the as-synthesized esters were confirmed by FT-IR, NMR, GPC, ESI–MS, and TGA characterization and their physicochemical and tribological properties were also evaluated according to standard methods. In view of the unique molecular structural design, the developed CPE displayed plentiful prominent technological specificities, which makes it plausible to be served as a potential high-performance base stock. Therefore, the findings of this study may provide some valuable insights for expanding the application scope of synthetic esters into various special industrial scenarios.
研究领域:
化学工程
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材料科学
·
润滑技术
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产品关联
DOI
高影响因子
MACROMOLECULES
·
2025
·
IF 5.2
Kaihao Chen,Tianwen Bai,YuLing Lin,Jun Ling,Xufeng Ni
Chemical synthesis of polymers from carbon dioxide (CO2) has been attracting a continuous amount of attention. This contribution explores the copolymerization of ethylidene-6-vinyltetrahydro-2H-pyran-2-one (EVL) synthesized from CO2 and 1,3-butadiene with various cyclic carbonates (CC) derived from CO2 and biomass diols. Following the “scrambling polymerizations” mechanism, EVL units are incorporated into polycarbonate backbones, resulting in random poly(ester-co-carbonate) P(EVL-co-CC) with functionalizable C═C double bonds. Kinetic studies and characterizations are conducted by NMR, MALDI-ToF MS, and SEC techniques. The obtained degradable P(EVL-co-CC)s having varying topologies, CO2 and C═C double bond contents, and glass transition temperatures are suitable for diverse applications. Modification in situ or via a postpolymerization “thiol–ene” reaction produces a copolymer with tunable tensile strength and amphiphilic and hydrophilic properties. This work presents an advancement in the utilization of CO2 to synthesize functional poly(ester-co-carbonate)s, contributing to the development of sustainable and green polymer chemistry.
研究领域:
材料科学
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绿色化学
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产品关联
DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2025
·
IF 4.6
Dan Zhao,Zewen Yan,Xincai Xiao
Organophosphorus pesticide residues pose considerable threats to the environment and public health and have become a global concern. This paper reports the development of a visual sensing platform for the detection of trichlorfon based on a carbon-based nanozyme (abbreviated as Fe-CDs) with peroxidase-mimetic catalytic activity in conjunction with acetylcholinesterase (AChE). The peroxide-mimetic enzyme activity of Fe-CDs can be inhibited by sulfhydryl (–SH) compounds, and AChE can decompose thiocholine (ATCh) to produce –SH-containing thiocholine (TCh), leading to the inability of Fe-CDs to oxidise 3,3′,5,5′-tetramethylbenzidine (TMB) to turn the solution blue, while trichlorfon can inhibit the activity of AChE, thereby recovering the blue colour. This platform achieves sensitive detection of trichlorfon with a linear range of 200–50,000 pM and a detection limit of 157.57 pM and has been successfully applied to the detection of trichlorfon in Chinese cabbage. In addition, encapsulating Fe-CDs, ATCh and TMB in sodium alginate hydrogels and using a smartphone and colour analysis software, a colorimetric hydrogel portable kit is developed, realising the simple and rapid detection of the trichlorfon residue in real samples. This study provides a direct, simple and rapid strategy for the detection of trichlorfon in agricultural products and offers a potential on-site detection tool for food safety monitoring.
研究领域:
环境科学
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食品安全
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生物化学
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产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2024
·
IF 3.8
Haoze Wang,Huizhe Zheng,Jie Jiang,Ling Zhao,Zhenhao Xi
Poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PCTG) is a high-performance engineering copolyester prepared using terephthalic acid (TPA), ethylene glycol (EG), and 1,4-cyclohexanedimethanol (CHDM). In this work, a complex reaction network of PCTG copolyesters involving homopolymerization and cross-polymerization was presented and the corresponding reaction mechanism was proposed. The reaction kinetics and mass transfer behavior were investigated using static thin film experiments, wherein the variation of the hydroxyl end-group concentrations of EG and CHDM with reaction time was separately determined. The results showed that the apparent reaction rate benefited from the high temperature, thin film thickness, and high vacuum conditions. Based on the pseudosteady-state assumption, the apparent reaction rate model coupled with mass transfer was evaluated and the model parameters including the reaction rate coefficient, equilibrium constant, and mass transfer coefficient were obtained, which were further used to simulate the polycondensation process. The concentration variation of EG and CHDM, and the rate variation of each reaction during polycondensation are discussed by combining the effects of homopolymerization, cross-polycondensation, and mass transfer. The concentration of EG was more sensitive to pressure than that of CHDM, which promoted the production of CHDM at high pressures. The proposed model is expected to provide guidance for the optimization of industrial production of PCTG/PETG and generalize to other copolyester systems.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2025
·
IF 7.3
Danqing Song,Qiqi Xie,Jiaying Zhang,Bing Wang,Yi Liu,Sheng Chen,Liuchun Zheng
The synthesis of traditional polyurea (PUR) involves toxic, hazardous, and harmful isocyanates. Sustainable biobased feedstocks are significant for future industrial development. A range of nonisocyanate poly(amide-urea) (NIPURs) are obtained by melt polycondensation from biobased dicarboxylic acids, urea, and diamines without catalysts and high pressure. Excessive hydrogen bonding in NIPURs leads to high crystallinity, which renders it difficult to obtain a polymer material with both high strength and satisfactory toughness. The hydrogen bonding content and distribution can be regulated by changing the molar ratio of dicarboxylic acids/urea and the structure of the dicarboxylic acids. It is remarkable that NIPURs exhibit excellent mechanical and thermal properties. Its yield strength is up to 61 MPa, tensile strength is as high as 7069 MPa, and it maintains an elongation at break of 241%; its melting point ranges from 166 to 200 °C and it maintains initial decomposition temperature (T5%) higher than 345 °C. The adjustable mechanical and thermal properties of NIPURs offer significant potential for various applications. This work could provide new insights into designing PUR with enhanced mechanical properties.
研究领域:
材料科学
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高分子化学
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产品关联
DOI
高影响因子
Polymers
·
2017
·Vol. 9
·期 11
·552
·
IF 3.364
Hongping Xiang,Xiaowei Wang,Guanghong Lin,Lu Xi,Yan Yang,Dehua Lei,Haihui Dong,Jiahui Su,Yanyan Cui,Xiaoxuan Liu
A novel UV-curable hyperbranched polyurethane acrylate (FHBPUA) with excellent flexibility is successfully synthesized based on a reaction of hydroxyl terminated hyperbranched polyurethane (regarded as core) with flexible semiadduct urethane monoacrylate (regarded as arms). The structure and property of FHBPUA is firstly analyzed and then utilized as functional additives to ameliorate the UV-curing and mechanical properties of epoxy acrylate resin. The degree of branching of FHBPUA turns out to be 0.82. Its thermal decomposition process consists of three different stages, and the glass transition temperature is around 65 °C. The freestanding FHBPUA film (~30 μm thickness) can be UV-cured within 3 s, and its flexibility is up to 1 mm. With the increase of FHBPUA content to 10 wt %, the UV-curing time of UV1000 film decreases from 6 to 3 s, flexibility strikingly increases from 10 to 1 mm, and adhesive force also improves from 5 to 3 grades, meanwhile its glossiness is not influenced by FHBPUA. In addition, a certain amount of FHBPUA can improve the tensile strength and elongation at break of UV1000 film. This novel FHBPUA can be used not only to develop flexible UV-curable freestanding films but also as functional additives to perfect other UV-curable compositions like coatings, inks and 3D printed parts.Keywords:hyperbranched polyurethane acrylate;UV-curing;flexibility;coatings;reinforcements
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Haiyan Liang,Yanchun Li,Siying Huang,Kaixi Huang,Xueyi Zeng,Qianwen Dong,Chengguo Liu,Pengju Feng,Chaoqun Zhang
Vegetable oil-based polymeric materials always suffer from relatively poor performance, such as lower tensile strength and glass transition temperatures, than petroleum-based polymeric materials, which greatly limit their practical applications. In this study, octahydro-2,5-pentalenediol (OPD) was synthesized from naturally occurring citric acid and used together with castor oil as the polyol blends for the production of bio-based waterborne polyurethane (PU) dispersions (PUDs). The effects of the OPD contents on the particle size and ζ potential of the resulting polyurethane dispersion, and the thermal stability, mechanical properties, and hydrophilicity of the resulting polyurethane films were systematically investigated. Taking advantage of the rigid cyclic structures of the OPD and the flexible fatty acid chain of castor oil, waterborne polyurethane (WPU) films with tailorable mechanical performance ranging from elastomeric polymers to rigid plastics were successfully prepared and characterized. The tensile strength of the samples increases from 9.5 to 22.3 MPa with the ratio between OPD and castor oil increasing from 0:10 to 5:5, whereas their elongation at break decreases from 192 to 12%. A significant increase in the glass transition temperature, transparency, and anticorrosive properties was observed for the resulting polyurethane films with increasing the OPD content. However, the thermal stability of the PU films exhibited a slight decrease as the OPD content increased. Moreover, the water contact angle exhibited a slight increase for the polyurethane films prepared from polyol blends compared to the WPU film prepared from pure castor oil. This work provides a novel route to tailor the performance of vegetable oil-based waterborne polyurethanes through the incorporation of rigid cyclic rings into soft polymer networks.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
MACROMOLECULES
·
2016
·
IF 5.554
Fang-Yi Qiu,Mei Zhang,Fu-Sheng Du,Zi-Chen Li
Functional polyesters and poly(carbonate)s (PCs) with controlled and on-demand degradation properties have great advantages for biomedical and pharmaceutical applications. Herein, we report a new kind of aliphatic PC that possesses the feature of oxidation promoted degradation. Two six-membered cyclic carbonates (C1 and C2) containing phenylboronic ester group have been synthesized from serinol (1) and 2-aminomethyl-2-methylpropane-1,3-diol (2), respectively. Both monomers could undergo well-controlled ring-opening polymerization (ROP) catalyzed by an organic base, but the 5,5-disubstituted C2 has the character of equilibrium ROP and a much slower rate than the monosubstituted C1. The copolymerization of C1 or C2 with trimethylene carbonate and its derivative leads to a series of copolymers. Two series of amphiphilic block copolymers (BPC1s and BPC2s) have been prepared from C1 and C2 using poly(ethylene glycol) as the macroinitiator. They are able to form nanoparticles with the diameters less than 150 nm. The H2O2-triggered decomposition of C1, C2, and their corresponding noncyclic model compounds was studied by 1H NMR, showing the consecutive process of oxidation, 1,6-elimination, release of CO2, and intramolecular isomerization or cyclization. The degradation of the block copolymer nanoparticles, investigated by 1H NMR, GPC, laser light scattering (LLS), and Nile Red fluorescence, can also be accelerated drastically by H2O2 following the similar mechanism but is affected by steric hindrance of the polymer chain and heterogeneous microenvironment inside the nanoparticles. The results of 1H NMR and LLS reveal that the nanoparticles of BPC1 and BPC2 exhibited different degradation profiles, with a slightly faster degradation rate for BPC2. Of particular interest, BPC2 nanoparticle is sensitive to as low as 0.02 mM H2O2.
研究领域:
材料科学
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生物医学工程
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DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 139
·期 18
·52059
·
IF 3.125
Xi Hou,Liwen Sun,Wei Wei,Darlene K. Taylor,Shengpei Su,Haibin Yu
Thermoplastic polyurethane (TPU) has become the focus of attention in the green and sustainable materials field because of its superior processability and recyclability. In this paper, a series of polylactic acid (PLA) and polycaprolactone (PCL)-based TPUs were successfully prepared by selecting PLA glycol, PCL glycol, isophorone diisocyanate (IPDI) and 1,4-butanediol (BDO) through a one-step polymerization method. The properties of the PLA and PCL-based TPUs are comprehensively characterized by Fourier transform infrared spectroscopy, 1 H NMR spectra, gel permeation chromatography, differential scanning calorimetry, thermalgravimetric analyzer, tensile test, dynamic mechanical analysis, scanning electron microscope, and so forth. The effect of hard segments content and PLA glycol molecular weight on the properties of PLA and PCL-based TPUs was systematically studied. Notably, their performance shows a certain degree of regularity and can be controlled by adjusting the hard segments content or the molecular weight of the PLA glycol. The prepared PLA and PCL-based TPUs have a tensile strength of 24.71 MPa, excellent thermal stability and out-standing damping performance. Its tan δ max of 1.40 and an effective damping temperature range of 50°C also make it a green damping material with great potential.
研究领域:
材料科学
·
绿色化学
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DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2022
·
IF 5.546
Jinbao Xu,Wenhao Xiao,Siheng Zhang,Zhixian Dong,Caihong Lei
Development of controllable, versatile and robust degradable polyurethane (PU) is of continued attraction regarding its wide application in the field of biology and medicine. Herein, new degradable poly(ether-ester-urethane) (PEEU) with amorphous and hydrophilic poly(1,5-dioxepan-2-one) (PDXO) diols as the soft segments and 4,4-diphenylmethane diisocyanate (MDI) and butane-1,4-diols (BDO) as the hard segments was synthesized by the one-shot two -step method in a controllable manner. The degradation behavior of PEEU with various compositions in vitro was investigated by observing the changes of weight loss, molecular weight and surface morphology during the 140 days of degradation. The weight loss and degradation rate of PEEU were faster than that of PU with semi-crystallized poly( ε -caprolactone) diols as soft segments and a surface to bulk degradation process was observed by scanning electron microscopy (SEM). In addition, the weight loss decreased by increasing the hard segments composition and the weight loss was mainly from the hydrolysis of ester linkages.
研究领域:
生物材料学
·
医学材料
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DOI
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2014
·Vol. 52
·期 8
·1185-1192
·
IF 3.245
Jinbao Xu,Junzhe Song,Stergios Pispas,Guangzhao Zhang
Ring-opening polymerization (ROP) of ε -caprolactone (CL) using salicylic acid (SAA) as the organocatalyst and benzyl alcohol as the initiator in bulk at 80 °C successfully proceeded to give a narrowly distributed poly( ε -caprolactone) (PCL). In addition, 2-hydroxyethyl methacrylate, propargyl alcohol, 6-azido-1-hexanol, and methoxy poly(ethylene glycol) were also used as functional initiators. The 1 H NMR, SEC, and MALDI-TOF MS measurements of the PCL clearly indicate the presence of the initiator residue at the chain end, implying that the SAA-catalyzed ROP of CL was through the activated monomer mechanism. The kinetic experiments confirmed the controlled/living nature of the SAA-catalyzed ROP of CL. Furthermore, the block copolymerization of CL and δ -valerolactone successfully proceeded to give poly( ε -caprolactone)- block -poly( δ -valerolactone). © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52 , 1185–1192
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）