高吸水性树脂

用热力学理论和相转变理论阐明了高吸水性树脂的吸水机理。解释了高分子链上的电荷密度、外界溶液离子强度以及交联度对吸水倍数的影响，并指出了影响吸水速率的因素。介绍了淀粉类、纤维素类、共聚合类、复合类以及可生物降解类高吸水性树脂近30年来的研究状况以及存在的问题，简要介绍了高吸水性树脂的应用。     

高吸水性树脂

综述了国内高吸水性树脂的研究进展,其中包括高吸水性树脂的制备方法、类型、影响其吸水性能的因素以及功能与应用。     

有机凹凸棒粘土的制备及复合高吸水性树脂的性能

有机凹凸棒粘土的制备及复合高吸水性树脂的性能;凹凸棒粘土;有机改性;高吸水性树脂     

高吸水性树脂

高吸水性树脂,可以吸收其本身重量的几百倍水。将水溶性高分子如羧甲基纤维素、聚丙烯酸钠盐或聚乙烯醇进行轻微的交联可以得到。由于其高吸水性、在压力下的高保水性和高增稠性,被广泛应用于纸尿布、生理巾、土壤保水剂、工业脱水剂、增稠剂等。     

高吸水性树脂研究进展

介绍了高吸水性树脂的结构、性能及其表征,结合经典理论与最新研究从热力学和动力学角度阐述其吸水机理,着重分析合成条件,组份和方法对高吸水性树脂性能的影响机制,简略地介绍了高吸水性树脂三十年来的发展及广阔的应用领域,并预测其研究与开发前景     

腐植酸高吸水性树脂研究进展

腐植酸（HA）是土壤腐殖质的主要成分,含有多种功能基团。随着HA基础和应用研究的不断深入,将具有反应活性和生物活性的HA引入到高吸水性树脂中,既能发挥HA改良土壤、增效化肥、刺激生长、增强抗逆和改善品质的功效,又可改善高吸水性树脂的吸水和耐盐性能,同时大幅度降低高吸水性树脂的制备成本。本文综述了近年来HA高吸水性树脂的...     

耐电解质高吸水性树脂

在简述高吸水性树脂吸水机理的基础上,综述了改善高吸水性树脂耐电解质性能的四种途径,结合聚合方法重点讨论了提高亲水性、引入长链疏不性单体以及合成两性聚合物三种改性途径。     

两性纳米复合高吸水性树脂的结构与性能

通过丙烯酸钠、阳离子单体丙烯酰氧乙基三甲基氯化铵(DAC)与钠蒙脱土原位溶液聚合成功地制备了具有插层结构的两性纳米复合高吸水性树脂. 其吸水性树脂吸水倍率和凝胶的抗压强度相对于聚丙烯酸钠基质均有较大提高. 吸水倍率最高可达2 380 g/g, 而凝胶的抗压强度提高到基质的180%左右. 由于复合材料结构上具有两性基团, 表现出对环境pH值特殊的应答性. 同时, 阳离子单体DAC的加入影响体系纳米结构的形成.     

有机-无机复合气凝胶研究进展

气凝胶具有低密度、低热导率、高比表面积及高孔隙率等优异性能,在隔热、传感、催化、吸附、储能等领域显示出良好的应用前景。但气凝胶的多孔网络结构也造成了其强度低和韧性差等问题,严重制约了气凝胶的实际应用,有机-无机复合是一种增强气凝胶力学性能的有效方法。而且,采用有机-无机复合方法制备气凝胶还可以赋予气凝胶阻燃等其他新颖的性能。本文综述了有机-无机复合气凝胶的新研究进展,分析其原理、合成方法及相关性能,指出了有机无机复合气凝胶的优势和存在问题并展望了未来的发展方向。     

有机-无机复合骨修复材料

本文对近5年来有机/无机复合骨修复材料研究领域的进展进行了综述,根据材料组分的特点分析其在生物相容性、生物降解性、生物活性以及力学性能等方面的优缺点,同时探讨了目前骨修复材料领域存在的问题,并对今后人工骨替代材料的发展趋势作出了展望。     

Hybrid Organic-Inorganic Composites Containing Mixed-Oxide Ceramics and High-Temperature Polymers

Abstract

The preparation of organic-inorganic composites by in-situ hydrolysis reactions is illustrated using two polymer-ceramic systems. The first consists of elastomeric poly(dimethylsiloxane) as the polymeric phase and silica, titania, or a silica-titania mixed oxide as the ceramic phase. In the second, the polymeric phase is either a polyamide or polyimide of high thermal stability and the ceramic phase is silica.     

有机-无机纳米复合水凝胶*

本文综述了近年来有机-无机纳米复合水凝胶领域的研究进展。针对无机成分的不同种类及复合形式,本文将目前已见报道的有机-无机纳米复合水凝胶划分为三类,分别为层状硅酸盐纳米插层复合水凝胶、粘土交联纳米复合水凝胶和二氧化硅纳米杂化复合水凝胶。阐述了三类纳米复合水凝胶的发展趋势,特别就它们的合成方法进行了详细归纳与总结。在此基础上,介绍了纳米无机成分对复合水凝胶的性能增强机理,并就三者之间的增强差异进行了说明。     

On the Effect of Organic Substitution of Silicon Alkoxides in Poly(Vinyl Acetate) Organic-Inorganic Composites

Abstract

Organic-inorganic composites (OICs) were prepared via the in-situ polymerization of an organically (phenyl) substituted trialkoxysilane, phenyltriethoxysilane (PhTEOS), in the presence of poly(vinyl acetate) (PVAc). The mechanical reinforcement above T _g previously observed in OICs of unfunctionalized organic polymers such as PVAc with acid catalyzed in-situ polymerized tetraalkoxysilane was not observed when the tetraalkoxysilane was replaced with PhTEOS. Although both systems are optically transparent and both exhibit a high degree of hydrogen bonding between the carbonyl of PVAc and the residual hydroxyls of the silicate, the polymerization of the alkoxide is different. The tetra-functional alkoxide polymerizes to form a load-supporting silicate network, leading to a high plateau in the tensile modulus above T _g, whereas the trifunctional alkoxide reacts to form primarily low molecular weight oligomers. These increase the T _g of the PVAc but do not provide mechanical reinforcement.     

Superabsorbent hydrogel composites

A new cost‐effective approach to enhance gel strength of superabsorbent hydrogels was invented. Superabsorbent hydrogel composites (SHCs) were prepared through an optimized rapid solution polymerization of concentrated partially neutralized acrylic acid in the presence of a crosslinking agent under normal atmospheric conditions. Kaolin was used as an inorganic component in the polymerization process to strengthen the hydrogel products. FT‐IR spectroscopy was used to confirm grafting of acrylic chains on to the surface of kaolin particles. Morphology of the products was studied by scanning electron microscopy (SEM). Compared with the kaolin‐free hydrogel (control), kaolin caused a reduced equilibrium swelling and swelling rate as low as 17–31% and 19–29%, respectively. Kaolin, however, resulted in enhanced gel strength as high as 21–35% compared to the control. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to study thermal properties of the composites. The SHCs exhibited higher thermal stability than the control. Meanwhile, changes in certain thermal transitions reconfirmed the chemical interaction of the acrylic chain with kaolin. These thermostabilized strengthened superabsorbent hydrogels may be considered as good candidates for agricultural application to retain more water under soil pressure. Copyright © 2003 John Wiley & Sons, Ltd.     

Superabsorbent Capability and High Retention Ability of China Clay (Kaolinite)/Polyacrylic Acid Composites for Aqueous Solution

Majority of superabsorbent polymers (SAPs) yet reported either have low gel strength or high production cost. Therefore, we synthesized a novel polyacrylic acid-grafted China clay (Kaolinite) super-absorbent polymer composite (SAPC) with high thermal stability, low cost of production and superior sorption and retention capability for water and salt solution. The resulting SAPCs were extensively characterized and analysed by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Results suggested that the composites were thermally stable. Water absorbency increased with increase of clay content up to 45%, while further increase in clay content decreased the water absorbency. Percentage of acrylic acid (AA) and clay by weight shows the optimum absorbency in 35% and 40% respectively. Crosslinker and initiator contents were optimized to be 0.5% and 0.3% by weight respectively. The resulting polymer composite showed high water absorbency of about 785 g/g and 103 g/g of 1% NaCl solution with above 90% retention ability at 50 oC.     

Lipase Immobilized in Organic-Inorganic Matrices

Enzyme lipase was immobilized with ferrite powder and deposited in layers on glass slides from lipase to a solution of silicone alkoxides. The highest hydrolytical activity was observed with the magnetic lipase prepared by mixing the paste of ferrite powder and lipase with tetramethoxysilane, 3-aminopropyltriethoxysilane and propyltrimethoxysilane. In a mixed reactor, the particles of the magnetic lipase were desintegrated by mechanical stirring which caused loosing the lipase linked to magnetic material and resulted in a significant drop of activity after magnetic separation. Transparent layers were prepared by dip- or spin-coating from partially hydrolyzed tetraethoxysilane and solutions containing methyltriethoxysilane with 3-aminopropyltriethoxysilane or tetraethoxysilane with 3-mercaptopropyltriethoxysilane. The lipases immobilized in films with magnetic particles were active in tests with 4-nitrophenyl butyrate and were not inhibited by 0,0-dimethyl-0-(2,2-dichlor-vinyl)-phosphate.     

有机-无机杂化膜的研究进展

有机-无机杂化膜由于具备了无机膜和有机膜各自的特点,具有良好的分离特性和物化稳定性,因而成为当前膜技术领域新型膜材料研究的热点.本文主要介绍了近年来国内外有机-无机杂化膜的研究现状、杂化膜的制备方法、结构和应用.     

Non-Conventional Curing of Organic-Inorganic Hybrids

Infrared and microwave curing of organic–inorganic hybrid materials was studied, in order to achieve the maximum conversion without detrimental effects due to the overheating or to the long-time permanence at high temperature. Partially cured poly(ethylene oxide)/silica hybrids were prepared by hydrolysis and subsequent condensation of precursors for 30 minutes isothermal heat treatment at 70°C. The conversion after the preliminary treatment is still low and requires an additional heating to complete the reaction. Three different thermal treatments were investigated: conventional heating, infrared heating and microwave heating. DSC characterisation of the obtained samples evidenced a drastic reduction of the treatment time when microwaves were used, requiring only a few seconds, compared to the hours-lasting conventional treatments.