纳米纤维素基水凝胶的制备及其在传感器中的应用进展

随着国家“双碳”战略的提出，可持续、可再生的原材料正在受到广泛的关注。作为地球上分布广泛的天然资源，纳米纤维素具有可再生、可生物降解、较好的热稳定性等特性。纳米纤维素表面富含的羟基使其成为制备水凝胶的理想材料。重点介绍了几种热门的纳米纤维素基水凝胶的制备方法，及其在传感器中的应用。研究表明，目前纳米纤维素基水凝胶的制备已存在相对环境友好的生产方法，纳米纤维素基水凝胶的传感性能在力学性能、灵敏度、稳定性、回收率等方面表现出优于通过常规传统材料制备的传感器，在解决成本问题后具有广阔的使用前景。     

碳气凝胶及其在污水处理中的应用

碳气凝胶是由碳纳米材料形成的三维多孔网络结构材料,具有比表面积大、孔隙率高、化学性质稳定和结构可调等优点,被广泛用于水污染处理中,用于去除油、有机溶剂、染料、重金属离子等。综述了碳气凝胶及其复合材料的研究进展,讨论了有机碳气凝胶、生物质基碳气凝胶、石墨烯基碳气凝胶三类碳气凝胶材料的组成、制备和吸附性能,总结了碳气凝胶在水处理中的应用并简要分析了碳气凝胶材料当前面临的挑战以及未来的发展前景。     

酚醛基炭气凝胶的研究进展

炭气凝胶是一种多孔纳米炭材料,具有低密度、高孔隙率、高比表面积、优异的导电性和良好的成型性能等优点,是炭材料研究的热点和重要方向。本文旨在通过阐明酚醛基炭气凝胶的制备原料和制备工艺的发展过程,从而突出未来酚醛基炭气凝胶的发展方向。基于此,本文首先重点介绍了酚醛基炭气凝胶的制备方法,主要包括溶胶-凝胶化、干燥以及炭化过程三个最主要的步骤;进而详述了以三种不同的前体,即间苯二酚、苯酚、生物质单宁/木质素分别制备酚醛基炭气凝胶的方法及其优缺点;接下来对酚醛基炭气凝胶作为吸附材料（气体吸附/液体吸附）的吸附量以及在电化学储能以及其他领域的应用进行了综述;最后对酚醛基炭气凝胶未来的研究方向和发展前景进行了总结和展望。文章指出,传统的以间苯二酚为原料辅以超临界干燥的方法制备的酚醛基炭气凝胶,原料成本较高,反应条件苛刻,实际生产应用受限;以苯酚取代间苯二酚,亦或是采用冷冻干燥等方法改进其制备工艺,可以大幅度降低原料和生产成本;但未来的发展方向和重点将是绿色、可再生的生物质原料（单宁、木质素、腰果酚等）及复合气凝胶材料的研发。因此,酚醛基炭气凝胶在未来的发展还需要进一步改进其制备工艺和方法,拓宽其原料来源,从而提高性能,扩大应用领域。     

生物质基碳气凝胶的研究进展

碳气凝胶是一种新型的纳米多孔碳材料,具有孔隙率高、比表面积大、导电性能优良、耐高温等优点,在催化剂载体、电容器及吸附材料等领域具有广阔的应用前景。与传统的碳气凝胶相比,生物质基碳气凝胶具有前驱体环保可再生的优势,可为生物质高值化、功能化利用提供新思路。本文在简单介绍生物质基碳气凝胶制备过程（包括溶胶-凝胶化、干燥、炭化）的基础上,重点介绍了3类来自不同生物质前驱体（植物纤维素、细菌纤维素和具有三维多孔结构的植物本身）碳气凝胶的制备方法,并对碳气凝胶及其复合材料在催化剂载体、吸附材料、超级电容器、锂离子电池方面的应用进行了综述,最后对生物质基碳气凝胶的研究方向和发展前景进行总结和展望。     

生物质灰硅资源高附加值利用的研究进展

生物质灰中含有具备化学活性的无定型硅，能用于合成高附加值产品。对生物质灰的组成、结构等方面进行了概述。在利用生物质灰合成凝胶方面，总结了近年利用生物质灰合成干凝胶、气凝胶、水凝胶的研究进展。综述了近年来利用生物质灰中的硅资源制备锂离子电池阳极材料、催化剂材料等方面的研究进展。通过对生物质灰硅资源的应用分析，提出生物质灰有望成为生产高附加值硅基材料的低成本前驱体来源，为生物质灰在工业上的资源化利用提供了重要的发展方向。     

纤维素基水凝胶的研究进展

纤维素是世界上最丰富的天然、可再生以及可生物降解的高分子材料，在化工、材料等领域有广泛的应用。本文主要对近几年来纤维素基水凝胶的研究进展进行了归纳总结。首先，介绍了纤维素基水凝胶的研究背景。其次，列举了纤维素水基凝胶的交联方法，主要有物理交联与化学交联。其中物理交联有氢键交联、疏水性交联、离子交联等，化学交联则是酯化交联、迈克尔加成、自由基共聚合、动态共价键交联等。最后，重点介绍了纤维素基水凝胶在可降解性、生物医学性、亲水性、吸附性、导电性等领域方面的应用。此外，对于纤维素基水凝胶材料在高机械性和产业化制备等方面的发展进行了展望。     

海藻酸钠基炭气凝胶的研究进展

海藻酸钠基炭气凝胶是以天然海洋生物质资源海藻酸钠为原料,通过凝胶、干燥和高温炭化制得,其生产原料来源广泛、制备工艺简单,并且十分符合绿色环保的理念,因此受到了国内外科研工作者的广泛关注。本文介绍了海藻酸钠基炭气凝胶的制备工艺,总结了其在超级电容器、锂离子电池、电催化和吸附领域的研究进展,并对该材料的进一步研究进行了展望。     

抗菌粘附型酪蛋白基纳米复合水凝胶的制备

近年来，水凝胶因其独特的网络结构和功能性受到了生物医药、食品环保等领域的广泛关注，其中以生物质材料为基体的绿色功能化水凝胶成为了重要研究方向。本研究以酪蛋白为基体，引入纳米氧化锌（ZnO NPs），通过“半溶解溶胶-凝胶酸化法”制备抗菌粘附型酪蛋白基纳米复合水凝胶。实验结果表明：所制备的纳米复合水凝胶具有立体的三维网络结构，孔径分布均一；当引入ZnO NPs用量为酪蛋白的3%时，其溶胀率可达79.19%；抗张强度和断裂伸长率分别可达1.9 MPa和137.4%；该水凝胶对于皮肤、玻璃、塑料、金属等多种材料表现出了优异的粘附性；且对大肠杆菌与金黄色葡萄球菌均具有良好的抗菌性能，在生物敷料领域展现出较好的应用前景。     

纤维素基超疏水材料的现状分析

近年来超疏水材料的应用领域越来越广泛,对超疏水材料的机械强度、耐磨性、透光度、重复利用性等性能方面的要求越来越高,原料的绿色环保性要求也日渐提高。生物质原料种类多、储量大,占据着可再生资源的主导地位。纤维素作为生物质原料的下游精细产品,具有绿色环保、储量大、应用灵活的优点。本文简单介绍了纤维素基超疏水材料的发展历程、特点及应用,重点分析了水热法、化学沉积法、原子转移自由基聚合和溶胶-凝胶法(纤维素/SiO₂超疏水材料和纤维素基气凝胶)等超疏水改性方法在制备纤维素基超疏水材料中的应用。最后对纤维素基超疏水材料的未来发展进行了展望。     

聚合物基水凝胶的研究进展及应用研究

聚合物基水凝胶作为一种高分子材料，拥有生物相容性、化学稳定性以及可调性等特性，能够广泛应用于医学、环境、能源等领域。本文主要涉及四种常见的高分子水凝胶，即聚丙烯酸水凝胶、聚乙烯醇水凝胶、聚氧乙烯水凝胶和聚丙烯酰胺水凝胶。通过文献综述和试验数据分析，总结了这四种水凝胶的制备方法、性能参数和应用范围。其中，聚丙烯酸水凝胶是最常用的一种，具有渗透性好、可生物降解等优点，在医学和卫生领域广泛应用；聚乙烯醇水凝胶则主要用于环境领域的水处理，具有良好的吸附性和可重复使用性能；聚氧乙烯水凝胶常用于药物控释和人工关节的缓冲材料；而聚丙烯酰胺水凝胶则被认为是一种具有广泛应用前景的新型材料。综上，高分子水凝胶作为一种重要的新型材料，在医学、环境、能源等领域具有广泛的应用前景，但同时也面临着许多挑战。对于未来研究的方向和重点，仍需要不断地深入研究和探索。     

生物质基多孔材料在保温材料中的研究进展

环保、节能、高效是保温材料未来的主要研究方向,开发以生物质为原料的保温材料是未来趋势。生物质基多孔材料是指以可再生的生物质为前驱体制备的多孔材料,其原料来源广,制备方法多样,具有孔隙率高、密度小、质量轻等优异特点,在保温领域有很大的应用潜力。本文概述了多孔材料的保温机理,并综述了近几年国内外对纤维素基、淀粉基、壳聚糖基、植物蛋白基多孔材料的研究,重点介绍了表面活性剂发泡法、冷冻干燥法、致孔剂法、模具热压法、溶剂交换相分离法等在生物质基多孔材料制备中的应用。分析了生物质多孔材料存在的问题,并对多孔保温材料未来的研究方向进行了展望。     

Edible hydrogel from gelatin and alginate as functional low-calorie noodle

There is an urgent need to develop edible hydrogels that can be served as a main dish with low-calorie content and high satiety value, yet are easy to digest. However, the development of such hydrogels remains challenging. In this study, low-calorie edible hydrogels were prepared from gelatin and sodium alginate (gel/SA hydrogels) through a facile acid soaking-drying method. These gel/SA hydrogels exhibited excellent mechanical properties with texture characteristics similar to that of Liangpi. The sensitivity of gelatin and acidified sodium alginate to pH resulted in a high swelling ratio of the hydrogels, contributing to weight retention in a simulated stomach environment and rapid degradation in a simulated intestinal environment. These properties indicate that these gel/SA hydrogels have a good prospect of being used as low-calorie food with high satiety value and are easy to digest. Konjac glucomannan can also be incorporated into the gel/SA hydrogels to further improve their biological functionality.     

Removal of heavy metals from model wastewater by using carboxymehyl cellulose/2‐acrylamido‐2‐methyl propane sulfonic acid hydrogels

A series of functional copolymer hydrogels composed of carboxymethyl cellulose (CMC) and 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS) were synthesized using γ‐radiations‐induced copolymerization and crosslinking. Preparation conditions were optimized, and the swelling characteristics were investigated. The ability of the prepared hydrogels to recover some toxic metal ions from their aqueous solutions was studied. The prepared hydrogel showed a great capability to recover metal ions such as: Mn⁺², Co⁺², Cu⁺², and Fe⁺³ from their solutions. The data revealed that the chelating ability of the prepared hydrogels is mainly dependent on their internal composition, in addition to the physical properties of the metal ion solution such as pH and metal ion concentration. The data show that the chelating ability of the prepared hydrogels increases by increasing the AMPS content in the hydrogel as well as the increment in the pH of the solution and the metal ion concentration. The prepared CMC/AMPS copolymer hydrogels are chemically stable enough to be reused for at least five times with the same efficiency. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Material Design for 3D Multifunctional Hydrogel Structure Preparation

Hydrogels are recognized as one of the most promising materials for e-skin devices because of their unique applicable functionalities such as flexibility, stretchability, biocompatibility, and conductivity. Beyond the excellent sensing functionalities, the e-skin devices further need to secure a target-oriented 3D structure to be applied onto various body parts having complex 3D shapes. However, most e-skin devices are still fabricated in simple 2D film-type devices, and it is an intriguing issue to fabricate complex 3D e-skin devices resembling target body parts via 3D printing. Here, a material design guideline is provided to prepare multifunctional hydrogels and their target-oriented 3D structures based on extrusion-based 3D printing. The material design parameters to realize target-oriented 3D structures via 3D printing are systematically derived from the correlation between material design of hydrogels and their gelation characteristics, rheological properties, and 3D printing processability for extrusion-based 3D printing. Based on the suggested material design window, ion conductive self-healable hydrogels are designed and successfully applied to extrusion-based 3D printing to realize various 3D shapes.     

具有快速响应特性的环境响应型智能水凝胶的研究进展

环境响应智能水凝胶应用于化学传感器、化学微阀、人造肌肉、药物控释载体、物质分离等领域时常常需要快速响应特性,提高智能水凝胶的响应速率成为了智能水凝胶研究领域的重要课题之一。本文主要综述了具有快速响应特性的环境响应智能水凝胶的构建策略与方法,重点介绍了3类具有不同结构的快速响应型智能水凝胶,即具有多孔结构的快速响应智能水凝胶、具有梳状结构的快速响应智能水凝胶以及具有微球复合结构的快速响应智能水凝胶。     

Effect of Potassium Methacrylate Content on Synthesis,Swelling, and Diffusion Characteristics of Acrylamide/Potassium Methacrylate Hydrogels

ABSTRACT

Hydrogels based on acrylamide (AAM) and potassium methacrylate (KMA) were synthesized by simultaneous free radical polymerization in aqueous solution using the redox initiator ammonium persulfate (APS) and N,N,N′N′-tetramethylethylenediamine (TMEDA) at room temperature. Eight different compositions of KMA hydrogels were prepared at a fixed concentration of N,N′,-methylenebisacrylamide (MBA) or diallyl phthalate (DP) as crosslinking agents. For all the AAM-KMA hydrogels, the percentage of swelling, swelling kinetics, and diffusion characteristics were investigated. It was found that higher swelling percentage values were obtained for hydrogels crosslinked with DP than for the conventional crosslinker MBA. The de-swelling characteristics of hydrogels were also studied in detail. The power law relationship of hydrogels was evaluated in saline solutions. Hydrogels formation was confirmed by IR spectroscopy. The thermal characteristics of these hydrogels were studied by using differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA) and revealed that MBA crosslinked AAM-KMA hydrogels show higher glass transition temperature (Tg) as well as higher decomposition temperatures (Td) than DP crosslinked AAM-KMA hydrogels. It is further confirmed from the studies that the DP crosslinked hydrogels have good swelling as well as de-swelling and salinity characteristics.     

Investigation of polyvinyl alcohol nanocomposite hydrogels containing chitosan nanoparticles as wound dressing

Polymeric hydrogels, water-swollen 3?D networks of the polymers, have found wide ranges of applications in the medical fields, such as wound care and wound dressing, in order to prevent infections. Prevention from microorganisms transfer in to the wounds is one of the ideal wound dressing duties of polyvinyl alcohol (PVA) hydrogels. In this study, at the start, under optimal conditions, nanoparticles of chitosan using ionotropic gelation method were synthesized and in the next step in order to achieve particles with a minimum size, they were evaluated by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). Then after to obtain a wound dressing with preferable properties, nanocomposite hydrogels using a combination of PVA and 5, 10 and 15?wt% chitosan nanoparticles were prepared through freezing-thawing cycles. The necessary features of PVA nanocomposite hydrogels for wound dressing were investigated. The dispersion state of nanoparticles and structure of samples were evaluated by SEM microscopy. The nanoparticle size and the nanoparticle size distribution of chitosan was determined using the dynamic light scattering test at the nanometer scale. The physical behavior of hydrogels such as swelling and gel fraction was studied and their mechanical properties were investigated by compressive test. Finally the antimicrobial test and biocompatibility as cell viability were carried out. The results proved that the PVA nanocomposite hydrogels fulfill the requirements of a good wound dressing with desirable characteristics such as favorable swelling and acceptable strength, excellent barrier against microbial penetration.     

木质纤维素复合生物质薄膜材料的功能化应用研究进展

为了解决传统石油基高分子薄膜不可降解等问题,纤维素、淀粉、壳聚糖等生物质薄膜材料因其具有绿色可降解性等优点而备受关注并展现出良好的发展前景。但生物质薄膜往往存在强度低、耐水性差等问题,限制了其进一步发展及功能化应用。本文综述了以木质纤维素作为添加剂增强生物质薄膜的力学强度、防水性、紫外屏蔽等性能的研究进展,重点探讨了不同结构性质的木质素和不同尺度的微纳米木质纤维素对生物质薄膜性能的影响,并进一步综述了木质纤维素复合生物质薄膜材料在包装材料、电极材料以及催化材料领域中的功能化应用研究进展。分析并展望了木质纤维素复合生物质薄膜在制备及功能化方面的优势、不足以及发展方向,以期为采用木质纤维素改良生物质薄膜的研究提供借鉴。     

Recovery of heavy metals from aqueous solution by using radiation crosslinked poly(vinyl alcohol)

Crosslinked poly(vinyl alcohol) (PVA) and PVA/acrylic acid hydrogels, prepared by γ‐irradiation, were used in the removal of heavy metals from aqueous solution. Comparative studies of the properties of the two hydrogels were made. The application of the prepared hydrogels as adsorbent materials for Cu²⁺, Co²⁺, and Ni²⁺ from aqueous solution was studied. The chemical and physical properties of the hydrogels, before and after adsorption of the heavy metal ions, were investigated by means of thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. The efficiency of such hydrogels for the recovery of metal ions was determined by atomic absorption and UV spectroscopic analysis. The effect of changing pH on the metal uptake was also studied. It was found that the prepared hydrogels have a substantial ability to adsorb metal ions from their solution. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1649–1656, 2004     

Control release of some pesticides from starch/(ethylene glycol‐co‐methacrylic acid) copolymers prepared by γ‐irradiation

Starch/(Ethylene glycol‐co‐Methacrylic acid) [Starch/(EG‐co‐MAA)] hydrogels were designed for controlled delivery of pesticides, such as Fluometuron (FH); Thiophanate Methyl (TF) and Trifluralin (TI) which are use in the agricultural field. The delivery device was prepared by using γ‐irradiation and was characterized by FTIR, DSC, and SEM. The swelling behavior of hydrogels as a function of copolymer composition and irradiation dose was detected. This article discusses the swelling kinetics of polymer matrix and release dynamics of Trifluralin from hydrogels for the evaluation of the diffusion mechanism and diffusion coefficients. The values of the diffusion exponent ‘n’ for both the swelling of hydrogels and the release of Trifluralin from the hydrogels have been observed between 0.56 and 0.86 when the MAA content in the polymers was varied from 20 to 80 wt %, respectively. It is inferred from the values of the ‘n’ that non‐Fickian diffusion mechanism has occurred for different EG/MAA compositions. The release rate from matrices prepared under different conditions was studied to determine which factors have the most affect and control over the hydrogel matrix release property. The preparation conditions such as EG/MAA hydrogel composition, pesticide concentration, type of pesticide and irradiation dose greatly affect the pesticide release rate, which also influenced by the pH and temperature of the matrix‐surrounding medium. The pesticide release rate decreased as the irradiation dose and pH increased, but it increased as the MAA content, pesticide concentration and temperature increased. The release rate of Trifluralin is the highest one, whereas the Fluometuron is the lowest. The properties of the prepared hydrogels may make them acceptable for practical use as bioactive controlled release matrices. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011