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Preparation of polysulfone-based block copolymer ultrafiltration membranes by selective swelling and

《化学科学与工程前沿（英文）》 2022年第16卷第5期页码 745-754 doi: 10.1007/s11705-021-2038-x

摘要： Selective swelling of block copolymers of polysulfone-b-poly(ethylene glycol) is an emerging strategy to prepare new types of polysulfone ultrafiltration membranes. Herein, we prepared nanoporous polysulfone-b-poly(ethylene glycol) ultrafiltration membranes by selective swelling and further promoted their porosity and ultrafiltration performances by using CaCO₃ nanoparticles as the sacrificial nanofillers. Different contents of CaCO₃ nanoparticles were doped into the solution of polysulfone-b-poly(ethylene glycol), and thus obtained suspensions were used to prepare both self-supported and bi-layered composite structures. Selective swelling was performed on the obtained block copolymer structures in the solvent pair of ethanol/acetone, producing nanoporous membranes with poly(ethylene glycol) lined along pore walls. The CaCO₃ nanoparticles dispersed in polysulfone-b-poly(ethylene glycol) were subsequently etched away by hydrochloric acid and the spaces initially occupied by CaCO₃ provided extra pores to the block copolymer layers. The porosity of the membranes was increased with increasing CaCO₃ content up to 41%, but further increase in the CaCO₃ content led to partial collapse of the membrane. The sacrificial CaCO₃ particles provided extra pores and enhanced the connectivity between adjacent pores. Consequently, the membranes prepared under optimized conditions exhibited up to 80% increase in water permeance with slight decrease in rejection compared to neat membranes without the use of sacrificial CaCO₃ particles.

关键词： block copolymers selective swelling ultrafiltration CaCO₃ nanoparticles sacrificial nanofillers

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Modeling of coal swelling induced by water vapor adsorption

Zhejun PAN

《化学科学与工程前沿（英文）》 2012年第6卷第1期页码 94-103 doi: 10.1007/s11705-011-1172-2

摘要： Gas adsorption-induced coal swelling is a well-know phenomenon. Coal swelling or shrinkage by adsorption or desorption of water vapor has not been well understood but has significant implications on gas drainage process for underground coal mining and for primary and enhanced coalbed methane production. Decreased matrix moisture content leads to coal shrinkage and thus the change of cleat porosity and permeability under reservoir conditions. Unlike gas adsorption in coal which usually forms a single layer of adsorbed molecules, water vapor adsorption in the coal micropores forms multilayer of adsorbed molecules. In this work, a model has been developed to describe the coal swelling strain with respect to the amount of moisture intake by the coal matrix. The model extended an energy balance approach for gas adsorption-induced coal swelling to water vapor adsorption-induced coal swelling, assuming that only the first layer of adsorbed molecules of the multilayer adsorption changes the surface energy, which thus causes coal to swell. The model is applied to describe the experimental swelling strain data measured on an Australian coal. The results show good agreement between the model and the experimental data.

关键词： multilayer adsorption vapour pressure coal shrinkage relative humidity permeability

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Preparation and swelling properties of a starch-g-poly(acrylic acid)/organo-mordenite hydrogel composite

Yan Zhang,Pingqiang Gao,Lin Zhao,Yizhong Chen

《化学科学与工程前沿（英文）》 2016年第10卷第1期页码 147-161 doi: 10.1007/s11705-015-1546-y

摘要： A novel hydrogel composite was prepared via inverse suspension polymerization using starch, acrylic acid and organo-mordenite micropowder with the crosslinker, , ′-methylenebisacrylamide and the initiator, potassium persulfate. Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, scanning electron microscopy, and energy dispersive spectroscopy confirmed that the acrylic acid was grafted onto the backbone of the corn starch, that the organo-mordenite participated in the polymerization, and that the addition of organo-mordenite improved the surface morphology of the hydrogel composite. The swelling capacity of the hydrogel composite was evaluated in distilled water, and solutions with different pH values, and various salt solutions. It was found that the incorporation of 10 wt-% organo-mordenite enhanced the water absorbency by 144% (from 268 to 655 g·g ) and swelling was extremely sensitive to the pH values, the concentration of the salt solution and cation type. Swelling kinetics and water diffusion mechanism of the hydrogel composite in distilled water were also discussed. Moreover, the hydrogel composite showed excellent reversibility of water absorption even after five repetitive cycles and the hydrogel composite exhibited significant environmental-responsiveness by changing the swelling medium from distilled water to 0.1 mol·L NaCl solution. In addition, the loading and release of urea by the hydrogel composite were tested and the nutrient-slow-release capability of this material was found to be suitable for many potential applications.

关键词： hydrogel composite environmental-responsiveness organo-mordenite starch acrylic acid

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掺砂率及初始干密度对改良膨胀土无荷膨胀率影响研究

杨俊,杨志,张国栋,唐云伟,陈红萍

《中国工程科学》 2014年第16卷第2期页码 73-78

摘要：

本文通过室内无荷膨胀率试验，对宜昌市某一级公路改建工程项目路段的膨胀土进行了研究。重点分析了无荷膨胀率与时间、掺砂比例、初始干密度之间的关系，试验研究表明：无荷膨胀变形主要分为快速膨胀、减速膨胀和最终稳定3 个阶段；在初始干密度一定时，风化砂改性土的无荷膨胀率会随着掺砂比例的增大先迅速降低然后缓慢降低，风化砂改性土的无荷膨胀率对较大的掺砂量不敏感；在相同的掺砂比例下，风化砂改性土的无荷膨胀率随着初始干密度的增大会迅速增大，它们之间有很好的线性相关性，膨胀土在进行路基填筑时，控制初始干密度有助于减小其膨胀变形，保证路基填土的稳定性。

关键词：膨胀土风化砂初始干密度掺砂比例无荷膨胀率

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Biodegradable polymethacrylic acid grafted psyllium for controlled drug delivery systems

Ranvijay KUMAR, Kaushlendra SHARMA

《化学科学与工程前沿（英文）》 2013年第7卷第1期页码 116-122 doi: 10.1007/s11705-013-1310-0

摘要： Polymethacrylic acid (PMA) was synthesized on the backbone of psyllium (Psy) by a microwave assisted method to prepare polymeric grafted materials designated as (Psy- -PMA). Various grades of Psy- -PMA were prepared by changing the degree of grafting from 35%–58% and the materials were then made into tablets. Swelling and biodegradability studies of the tablets were carried out. Acetyl salicylic acid was incorporated in the various Psy- -PMA samples and tablets were prepared to study the in vitro drug release in acidic (pH= 4), neutral (pH= 7), and basic (pH= 9) media. In the acidic medium, the swelling was more than 1300%. In addition, the biodegradable Psy- -PMA had the highest drug release in the acidic medium. This may be attributed to Fickian diffusion since the drug and the medium in which it was released have the same acidic nature.

关键词： psyllium acetyl salicylic acid in-vitro drug release swelling biodegradation

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Studying the stress-suction coupling in soils using an oedometer equipped with a high capacity tensiometer

Trung Tinh LE, Yu-Jun CUI, Juan Jorge MU?OZ, Pierre DELAGE, Anh Minh TANG, Xiang-Ling LI

《结构与土木工程前沿（英文）》 2011年第5卷第2期页码 160-170 doi: 10.1007/s11709-011-0106-x

摘要： In the context of research into deep nuclear waste disposal, various works have concerned the hydromechanical behavior of Boom clay, a stiff plastic clay extracted in the SCK-CEN Underground Research Laboratory near the Mol City (Belgium), at a depth of 223 m. Due to some amount of smectite minerals in the clay fraction, Boom clay exhibits swelling properties when hydrated under low stresses. To investigate some aspects of the hydromechanical behavior of Boom clay, oedometer compression tests were carried out on samples of Boom clay close to saturation and submitted to an initial suction. During oedometer compression, the changes in suction with increased vertical stress are monitored by means of a high capacity tensiometer installed at the bottom of the sample. Some aspects related to hydromechanical couplings are examined through the investigation of the changes in suction during oedometer compression, a somewhat delicate and poorly documented experimental approach. A comparison is also made with a completely different soil sample under suction, i.e. a statically compacted unsaturated low plasticity silt. Some technical difficulties typical of this new experimental approach are first described in detail so as to optimize the interpretation of the data obtained. The experiment allows the determination of the point at which suction is changed to positive pressure during compression. Below this point, the ratio between the vertical stress and the change in suction are determined. Above this point, the data show that positive pore pressures are dissipated in a common way. The suction/stress behavior during unloading is also described and discussed. Finally, an interpretation in terms of microstructure effects is provided for both samples. The experimental approach initiated here seems to provide interesting further application to better understand hydromechanical couplings in natural soils in relation with suction increase during stress release.

关键词： Oedometer tensiometer swelling physicochemical and mechanical effects stress/suction coupling soil plasticity

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对双层组件4D打印可逆性的初步研究 Article

Amelia Yilin Lee, Jia An, Chee Kai Chu, Yi Zhang

《工程（英文）》 2019年第5卷第6期页码 1159-1170 doi: 10.1016/j.eng.2019.09.007

摘要：

增材制造的快速发展和形状记忆聚合物材料的进步推动了四维（4D）打印技术的进展。随着设计方面的不断改进，逐渐证明有可能实现可逆4D打印或双向4D打印。这项技术将完全消除对人为干预的需要，因为编程完全由外部刺激驱动，这使得4D打印部件可以在多个周期内启动。本研究提出了一种新的可逆4D打印驱动方法，其中弹性体的溶胀和热量用于编程阶段，以及热量用于恢复阶段。本研究的主要重点在于自驱动设计这一步骤。为了实现对弯曲的控制，已经开发了一种简单的预测模型用于研究曲率。此外，为了更好地了解模型对曲率的预测程度，对参数、温度和弹性体厚度也进行了研究。采用这种方式理解曲率可以提供对可逆4D打印结构的高度控制。

关键词： 4D打印增材制造形状记忆聚合物可逆4D打印双向4D打印溶胀弹性体

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基于实时CT扫描技术的CO₂和N₂交替注入条件下煤吸附膨胀和解吸收缩规律研究 Article

张广磊, P.G. Ranjith, Herbert E. Huppert

《工程（英文）》 2022年第18卷第11期页码 88-95 doi: 10.1016/j.eng.2022.03.010

摘要：

深部煤层是分布最广泛的适宜二氧化碳（CO₂）地质封存的地层之一，且通常位于大型CO₂排放源附近。将CO₂注入到煤层中具有巨大的CO₂封存潜力，同时可以提高煤层气的采收率（CO₂-ECBM）。近年来，多个国家在煤层中已经开展了CO₂-ECBM 的先导试验，并取得了良好的可行性验证效果。然而，目前CO₂-ECBM先导实验仍存在技术问题需要解决，即CO₂的注入会引起煤层渗透率降低进而影响长期注入能力。本文采用原位同步辐射X射线显微CT扫描技术，首次在原位条件下直接证明了注入氮气（N₂）可以置换解吸CO₂并减小因CO₂吸附引起的煤基质膨胀，进而重新打开因为CO₂吸附而闭合的裂隙促使渗透率回升。研究结果表明，煤层中注入经过简单处理的烟道气（主要成分为N₂和CO₂），是技术上可行的CO₂-ECBM 替代方案。首先，发电厂产生的烟道气可以在去除颗粒物后直接注入，从而避免了较高的CO₂分离成本。其次，N₂的存在可以使煤层保持较高的渗透率，实现长期CO₂注入封存和煤层气增产。总之，深部煤层中注入烟道气一方面可以实现CO₂大量封存，另一方面可以强化煤层气开采，为煤矿实现净零排放提供了一条有效途径。