JOURNAL OF MEMBRANE SCIENCE
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2024
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IF 8.4
Ke Xiang,Zhen-Liang Xu,Yong-Jian Tang
Recent studies have shown that the temperature and time of the heat curing process have important effects on the nanofiltration (NF) membrane structure and properties. However, the mechanism of the relative humidity (RH), as one of the important factors in the heat curing of NF membranes, is still unclear. To analyze the specific effect of RH, we compared the heat curing results of the NF polyamide (PA) membranes fabricated with different monomer concentrations at various RH. The nanofiltration performance of the membranes appeared to be non-uniform when the RH was in the range of 40 %–60 %. Within the appropriate RH range , the rejection of Na 2 SO 4 was preserved at about 98.5 % for the manufactured NF membranes. At high concentrations, the increasing RH created a discontinuous condensate layer on the PA layer surface, which affected the morphology and physicochemical properties of the NF membrane causing a doubling of pure water permeability (PWP) to 8.33 L m −2 h −1 ·bar −1 . At low concentrations, the PA layer was not significantly changed with the increase of RH, but the evaporation of water from the smaller capillary pores in its PES substrate was slowed down, which reduced the capillary stress on the substrate and prevented the collapse of the substrate pore size, resulting in a nearly 20 times increase in its PWP to 39.7 L m −2 h −1 ·bar −1 . This work reveals the effect of RH during heat curing and gives significant guidance to the design and synthesis of high-performance NF membranes.
研究领域:
材料科学
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环境工程
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DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2024
·
IF 3.8
Ke Xiang,Hui-Hui Ping,Zhen-Liang Xu,Liwei Zhuang,Yong-Jian Tang
Heat curing is an essential step for industrial-scale fabrication of polyamide nanofiltration membranes, which can improve the membrane stability and promote the membrane element encapsulation feasibility, but thermal stresses cannot be avoided during this process. In this study, oven and microwave were used to cure nanofiltration membranes, and the results showed that compared with oven heat curing, the flux dispersion of nanofiltration membranes cured using microwave heat curing was reduced from 0.318 to 0.093, and its Na2SO4 rejection dispersion was reduced from 0.063 to 0.005, providing a tremendous improvement in the uniformity of nanofiltration membranes. The effect of the thermal stress distribution on the uniformity of nanofiltration membranes during heat curing was elucidated by numerical simulations. The fast microwave heating speed and uniform temperature distribution reduced the defects of the PA layer due to uneven thermal stress distribution. In conclusion, this study demonstrated the effect of thermal stress on membrane uniformity in different thermal curing modes, which provides good prospects for the application of microwaves in the field of nanofiltration membranes.
研究领域:
材料科学
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环境工程
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DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2018
·Vol. 136
·期 14
·47310
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IF 1.901
Xiaoyong Zhang,Jinmei He,Lipei Yue,Yongping Bai,Huihui Liu
The development of adhesive tapes that can be applied at high temperature is a major challenge for pressure-sensitive adhesives (PSAs). To date, the heat resistance of PSAs has not been investigated in sufficient details. In this study, based on the relationship between curing structures and properties, a series of acrylic PSAs with excellent heat resistance were prepared. Commercial zirconium acetylacetonate (ZrACA), desmodur L75 (L75), and N , N , N ′, N ′-tetrakis(2,3-epoxypropyl)- m -xylene-α,α′-diamine (GA240) were employed as heat-curing agents. Trimethylolpropane triacrylate (TMPTA) was used as ultraviolet (UV)-curing agent to form semi-interpenetration polymer network structures after UV exposure. The influences of different curing agents on the thermal stability, adhesion performance, gel fraction, and viscoelastic of PSAs were explored. The results showed that the PSAs cured by L75, GA240, and TMPTA exhibited excellent heat resistance. Especially, when the content of L75 was 1.0 wt %, the PSAs could be peeled off substrate without residues on substrate surface after treatment at 170 °C for 4 h, while the nonmodified acrylic PSAs possessed residues after treatment from 110 °C. The cured PSAs adhesive performance was evaluated showing maximum 180° peel strength of 16.7 N/25 mm comparable to current PSAs. These resulting PSAs showed high heat resistance and they are suitable for a broad range of special fields. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47310.
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
JOURNAL OF APPLIED POLYMER SCIENCE
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2018
·Vol. 136
·期 17
·47428
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IF 1.901
Zhihao Liang,Xiaomei Wang,Liangting Feng,Xuefen Wu
A novel solder resist ink for inkjet printing containing the ultraviolet (UV) and thermal dual curing oligomer is introduced in this work. Three kinds of acrylic monomers for the synthesis of the oligomer are successful prepared and their structures are determined by Fourier transfer infrared. Both UV curing process and thermostability are monitored under UV differential scanning calorimetry and thermogravimetric analysis. For the photoreaction process, the oligomer using Lauryl methacrylate as the material of copolymerization possesses the highest reactivity and conversion of carbon–carbon double bond. Besides, this kind of oligomer also owns excellent thermostability, just losing 5.9% of its weight at 288 °C. The solder resist inks containing the oligomers and jetting by the inkjet printer are tested with the adhesion, soldering resistance, and other performances, presenting the outstanding heat resistance and wide application prospects. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47428.
研究领域:
材料科学
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聚合物化学
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DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
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2024
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IF 7.4
Qianshun Cui,Tongcai Wang,Guangshuai Gu,Rihan Zhang,Tingting Zhao,Zhifeng Huang,Gong Wang,Fei Chen
The establishment of a lunar base is crucial for lunar studies, resource extraction, and advancement in deep space exploration . Considering the limitations of rocket capacity and Earth-Moon transportation costs, lunar regolith is regarded as the most practical material for lunar base construction. Consequently, the in-situ additive manufacturing technology for simulated lunar regolith has been widely studied in recent years. This paper proposes a novel additive manufacturing approach for lunar regolith simulants. The simulants and several resins were mixed into a paste with high simulant content of 86 wt%, which was suitable for extrusion-based additive manufacturing process . To fully leverage the lunar environment , the feasibility of the ultraviolet (UV) and thermal curing of the resins was first verified, which was followed by the validation of the lunar regolith paste with the solid content of 86 wt%. After the characterization of the ultraviolet and heat curing properties, the paste was further 3D printed via the extrusion-based device. The extruded paste underwent preliminary curing in a UV environment and was then heated to approximate the daytime lunar conditions, achieving complete curing of the printed component. The cured parts exhibited a compressive strength of 9.83 ± 1.07 MPa, meeting the requirements for infrastructure construction in the low-gravity lunar environment. This work offers significant implications for future in-situ construction on the Moon using extrusion-based additive manufacturing of lunar regolith.
研究领域:
材料科学
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航天工程
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建筑技术
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DOI
高影响因子
DESALINATION
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2024
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IF 8.3
Tong Wu,Liu-Kun Wu,Hai-Tao Xu,Zhen-Liang Xu,Yong-Jian Tang
The TFC RO/NF membranes are the predominant membranes applied in desalination , and heat curing is an essential step in its industrial production, which increases the polyamide cross-linking degree and facilitate packing but leads permeability decrease. Nevertheless, the mechanism of heat curing on TFC membranes permeation resistance changes is still ambiguous. Figuring it out will aid in crafting a more effective optimization strategy in high flux membrane preparation. Herein, we prepared a range of TFC RO/NF membranes with various monomer concentrations on different substrates and quantified the permeation resistance changes by a resistance-in-series model. For nascent TFC RO/NF membranes, the PA layer provided almost all permeation resistance. After heat curing, the substrate exhibited a marked increase in permeation resistance. The change in the permeation resistance composition was further exacerbated by the decrease in monomer concentration. For TFC NF membranes with heat curing, the proportion of substrate permeation resistance increased significantly, rising from 31.62 % to 75.05 %. This study made a comprehensive analysis of the impact of the permeation resistance in TFC RO/NF membranes caused by heat curing, enriched the insight into the impact of heat curing on TFC membranes, and helped to prepare TFC membranes with better desalination performance.
研究领域:
材料科学
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环境工程
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产品关联
DOI
高影响因子
Polymers
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2024
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IF 4.7
Jinyu Zhang,Dezhi Qu,Shuyu Wang,Shien Qi,Huajiang Zuo
In this study, polyacrylic acid hydrogels were prepared by modulating the cross-linking agent mass ratio using UV and heat curing methods. The structures and properties of the hydrogels were characterized and analyzed using Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The results showed that the mechanical properties of the hydrogels prepared through UV curing were better than those prepared through heat curing. The maximum mechanical tensile strength of 139 kPa was achieved at a cross-linking agent mass ratio of 3.85% with 20 min of UV curing, and the maximum mechanical compressive strength of 0.16 MPa was achieved at a cross-linking agent mass ratio of 2.91% with 20 min of UV curing. However, the hydrogels prepared by heat curing had a higher tensile strength than those prepared using the heat curing method. In addition, the thermally cured hydrogels had higher water absorption and adsorption properties. Moreover, the PAA hydrogels prepared at cross-linking agent mass ratios of 1.91 and 2.91% with 2 h of the heat curing method had the best swelling properties. Moreover, the increase in the cross-linker mass concentration led to a decrease in the pore size and porosity and to a more compact structure.
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
PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2025
·
IF 2.5
Shengyuan Liang,Yeyun Meng
A modified amine chain segment was synthesized through a reaction between polyethylene glycol (PEG) and bisphenol A epoxy resin. Subsequently, organically modified montmorillonite (OMMT) was prepared via ammonium salt formation under acidic conditions. Using phase inversion technology, an epoxy resin/organic montmorillonite composite emulsion was successfully fabricated, employing a minimal amount of an epoxy emulsifier with OMMT as a co-emulsifier. Thermal curing of this emulsion yielded the final OMMT/epoxy resin composites. Structural characterization was performed using Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) to confirm the chemical composition of the synthesized amine. X-ray diffraction (XRD) analysis verified the successful intercalation and exfoliation of montmorillonite during organic modification. The emulsion system was further evaluated through dynamic light scattering (DLS) and zeta potential measurements, which demonstrated that OMMT incorporation significantly enhanced emulsion stability by optimizing particle size distribution and increasing surface charge density. Thermal analysis revealed notable improvements in the thermomechanical properties of the composites, confirming the reinforcing effect of OMMT within the epoxy matrix.
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
POLYMER DEGRADATION AND STABILITY
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2020
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IF 4.032
Peng Wang,Ming Liu,Qichao Ran
Based on the weight loss and small molecule volatiles released during the thermal curing process of three kinds of benzoxazines , bisphenol A/aniline type benzoxazine (BA-a), p-cresol/diamine type benzoxazine (MPH-mda) and 2,4-xylenol/4,4′-methylenebis-(2,6-diisopropyl) aniline type benzoxazine (DMPH-mdpa), their curing mechanisms and the weight-loss mechanisms were studied. The weight-loss ratios and structure changes of these benzoxazines during the curing process were studied by weighing method, Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The volatiles released from these benzoxazines during different curing stages were collected by a self-made experimental device. The structures of these volatiles were characterized by FTIR and proton nuclear magnetic resonance spectroscopy ( 1 H NMR). The results showed that the mixtures of imine , triazine , aniline and Schiff base were released from the cracking of the intermediate during the thermal curing of BA-a. Compared with BA-a, the weight loss of MPH-mda was smaller, and its volatile was a small amount of stable diamine type Schiff base. For DMPH-mdpa, because all active reaction points on benzene ring were occupied by alkyl groups , it cannot form effective polymer structures after ring-opening reactions, which led to that DMPH-mdpa had the most weight loss during the curing process, and mainly generated phenol type volatiles.
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
Journal of Renewable Materials
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2021
·Vol. 9
·期 12
·2093-2117
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IF 1.67
Li Rumeng,Zhan Guozhu,Ma Qi,Yang Yunhe,Liu Xiaoyun,Zhang Yitong,Zhuang Qixin
To explore the influence of substituent groups on thermally induced curing, eight new bio-based benzoxazines containing different substituent groups with different electron negativity and volumes were synthesized. The thermal curing of these bio-based benzoxazines was studied in detail.
Combined with the curing reaction kinetics, simulation and calculation of Highest Occupied Molecular and Lowest Unoccupied Molecular values, the spatial and electronic effects of different substituent groups on the curing of benzoxazine was explored. It was found that when the substituent
was located at the position directly connected to the N atom, the steric hindrance effect of the group was dominant. When the substituent group was located on the benzene ring connected to the O atom, both the electronic effect and the spatial effect influenced the curing of benzoxazine. When
an electron-withdrawing group was connected ortho position to the O atom, the curing reaction was promoted due to the decreased electron cloud density of O- on the oxazine ring, making the C-O bond easier to break. When an electron-donating group was connected to the meta position
of the O atom it also promoted the curing reaction, possibly because it increased the electron cloud density of the +CH2 reaction site and thereby facilitated electrophilic substitution via attack of +CH2 on the cross linking reaction centre. This
work provides a deeper understanding of how spatial and electronic effects of substituents affect the curing of benzoxazine.
研究领域:
材料科学
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有机化学
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DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2022
·
IF 4.326
Liu-Kun Wu,Qiu-Yu Zhu,Lan-Qian Li,Zhen-Liang Xu,Shuang-Mei Xue,Chen-Hao Ji,Chuyang Y. Tang,Liwei Zhuang,Yong-Jian Tang
Recent studies show that heat curing has a great influence on the performance of polyamide nanofiltration (NF) membranes. In this work, nascent polypiperazine-amide NF membranes were pretreated before heat curing to reveal the change in permeation resistance caused by heat curing. Aqueous solutions containing a series of organic molecules (glycerol, raffinose, α-cyclodextrin, and polyvinylpyrrolidone) with different molecular weights were used to treat the polypiperazine-amide NF membrane via different immersion approaches before heat curing. These organic molecules play a role in filling and alleviating the collapse and shrinkage of the membrane structure during heat curing and in further protecting the membrane from permeance loss. Furthermore, the organic molecules were used to regulate the shrinkage of the membrane structure in different immersion approaches to clarify the proportion of permeability change attributed to the shrinkage in different membrane layers during heat curing. Through a resistances-in-series model calculation, the permeation resistance of the polyamide layer was found to have decreased from 0.0523 to 0.0329 h bar m–1 after being pretreated with glycerol and that of the polyether sulfone substrate decreased from 0.1651 to 0.0033 h bar m–1. This work proves that protecting the ultrafiltration membrane from drying during heat curing is the key to maintaining the performance of the thin-film composite membrane. This research is instructive for a better understanding of the permeance loss of the NF membrane during heat curing and the optimization of the heat treatment procedure in industrial processes.
研究领域:
材料科学
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环境工程
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产品关联
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2017
·Vol. 55
·期 17
·2815-2823
·
IF 2.952
Zhefu Li,Yichun Yuan,Binling Chen,Yong Liu,Jun Nie,Guiping Ma
An inorganic–organic hybrid material, poly(dimethylsilylene ethynylenephenyleneethynylene) (PMSEPE), was synthesized in a mild condition and its microfiber was successfully produced by melt electrospinning. The electrospinning parameters, which affected the morphology and diameter of fibers, were well investigated. To maintain the fiber structure at thermal cured temperature (above melting point), the PMSEPE fibers were enhanced via thiol-yne photo polymerization. Followed by the thermal curing reaction, the heat-resistance and mechanical properties of fibers were enhanced. The mechanism of two-step curing was explored and confirmed by means of Fourier transform infrared, differential scanning calorimetry, and X-ray photoelectron spectroscopy (XPS). Thermaogravimetric analysis and scanning electron microscopy results show that after carbonization at 800 °C, the two-step cured fibers had only a small weight loss (20%) and the fibers can still maintain the original morphology. Moreover, the two-step cured fiber exhibited a high tensile strength (55.4 MPa) and a small elongation at break (0.02%). All the results indicate that the fibers could be applied as fiber-reinforced materials. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2815–2823
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
危险品化学品经营许可证（带存储）