共查询到20条相似文献,搜索用时 796 毫秒
1.
快速pH响应丝胶/聚甲基丙烯酸互穿网络水凝胶的合成及表征 总被引:3,自引:0,他引:3
采用同步互穿网络方法制备丝胶蛋白(SS)/聚甲基丙烯酸(PMAA)为组分的互穿网络(IPN)水凝胶. 研究了互穿网络水凝胶对介质pH的刺激响应性能. 结果表明, IPN水凝胶具有强烈的pH刺激响应性能. 在pH=9.2的缓冲溶液中, -COOH解离成 -COO-, 渗透压与网络之间的静电排斥作用导致IPN的溶胀度增大; 当pH减小时, 溶胀度随之减小. IPN水凝胶具有快速退溶胀速率及可逆溶胀-收缩性能. 相似文献
2.
3.
考察了以牛乳清蛋白(BSA)为模型药物,通过相平衡分配法制备载药瓜胶(GG)/聚丙烯酸(PAA)互穿聚合物网络(IPN)水凝胶的工艺条件.借助紫外可见光谱仪研究了载药水凝胶在结肠酶存在下的控制释放行为.结果表明:载药容量(CM)随瓜胶、丙烯酸用量的增加而下降,半IPN水凝胶的Cm较全IPN的略大;结肠酶能明显提高半IPN与全IPN中的BSA释放速率,且提高幅度随GG含量的增加而加快,GG/PAA IPN水凝胶具有结肠定位降解的特性,有望成为靶向结肠给药的理想载体材料. 相似文献
4.
网络间含离子键的聚氨酯/接枝乙烯基酯树脂互穿聚合物网络 研究 总被引:2,自引:0,他引:2
分别以双酚-A型环氧树脂E-51和聚醚型环氧树脂E-46为原料合成了两种二乙胺-环氧树脂和加成多元醇(分别命名为AE-51,AE-46),将其和甲基丙烯酸一起用于合成聚氨酯/接枝乙烯基酯树脂(PU/接枝VER)互穿聚合物网络(IPN),使之在两个网络间形成离子键。实验结果表明,这类新型的IPN材料中两个网络间的互穿程度与相容性进一步提高,从而导致刚性的接枝VER对弹性的PU网络有更好的增强效果。DSC和FTIR的测定结果表明,在含AE-51的IPN中,由于离子键的作用使PU网络硬段的有序结构遭到很大程度的破坏,与AE-51和PU网络中的硬段以及VER网络有较好的相容性有关,因此这类IPN材料具有较好的力学性能。 相似文献
5.
6.
7.
8.
9.
10.
采用分步悬浮聚合法制备了聚二乙烯基苯/聚丙烯酸甲酯(PDVB/PMA)大孔互穿聚合物网络,将其中的聚丙烯酸甲酯用乙二胺氨解,合成了具有疏水/亲水性能的聚二乙烯基苯/聚(N-2-氨基乙基丙烯酰胺)(PDVB/PNAEAM)大孔互穿聚合物网络(IPN);测定了该树脂的孔结构、含水量、弱碱交换量和溶胀性能;测定了该树脂对水杨酸在不同温度下的吸附等温线,利用热力学函数关系计算出了吸附焓、自由能和熵.推测PDVB/PNAEAM IPN树脂中疏水性的PDVB一网具有疏水作用吸附能力、亲水性的PNAEAM一网具有氢键作用吸附能力.动态吸附及脱附实验表明湿态PDVB/PNAEAM IPN树脂对水溶液中水杨酸的饱和吸附量达到46.1mg/mL.树脂可以通过4%NaOH溶液再生.PDVB/PNAEAM IPN树脂在分离工业废水中水杨酸等芳香有机酸有良好的应用前景. 相似文献
11.
H. L. Frisch Yongpeng Xue 《Journal of polymer science. Part A, Polymer chemistry》1995,33(12):1979-1985
A hybrid inorganic/organic interpenetrating polymer network (IPN) of a three-dimensional network structure zeolite crystal (13X, powder) and crosslinked or linear polystyrene (PS) was prepared and characterized by differential scanning calorimetry (DSC), solid-state13C-NMR, and scanning electron microscopy (SEM). The size and shape of the crystalline zeolite particles were revealed on SEM micrographs in both the pure zeolite and the IPNs. Solubility tests and the results of DSC with solid-state 13C-NMR confirm that some organic PS chains are incorporated within the internal three-dimensional channels of the zeolite particles. We speculate that the internal PS chains may adopt an extended “one-dimensional” conformation and exhibit no bulk polymer glass transition. These novel hybrid inorganic/organic IPNs are a new kind of IPN structure. © 1995 John Wiley & Sons, Inc. 相似文献
12.
《Solid State Sciences》2000,2(3):313-334
The latest developments in inorganic membranes are closely related to recent advances in solid state science. Sol–gel processing, plasma-enhanced chemical vapor deposition and hydrothermal synthesis are methods that can be used for inorganic membrane preparation. Innovative concepts from material science (templating effect, nanophase materials, growing of continuous zeolite layers, hybrid organic–inorganic materials) have been applied by our group to the preparation of inorganic membrane materials. Sol–gel-derived nanophase ceramic membranes are presented with current applications in nanofiltration and catalytic membrane reactors. Silica membranes with an ordered porosity, due to liquid crystal phase templating effect, are described with potential application in pervaporation. Defect-free and thermally stable zeolite membranes can be obtained through an original synthesis method, in which zeolite crystals are grown inside the pores of a support. Hybrid organic–inorganic materials with permselective properties for gas separation and facilitated transport of solutes in liquid media, have been successfully adapted to membrane applications. Potential membrane developments offered by CVD deposition techniques are also illustrated through several examples related to the preparation of purely inorganic and hybrid organic–inorganic membrane materials. 相似文献
13.
Yanhui Cui Qinghe Zhao Xiaojun Wu Xin Chen Jinlong Yang Yuetao Wang Runzhi Qin Shouxiang Ding Yongli Song Junwei Wu Kai Yang Zijian Wang Zongwei Mei Zhibo Song Hong Wu Zhongyi Jiang Guoyu Qian Luyi Yang Feng Pan 《Angewandte Chemie (International ed. in English)》2020,59(38):16594-16601
Aqueous zinc (Zn) batteries (AZBs) are widely considered as a promising candidate for next‐generation energy storage owing to their excellent safety features. However, the application of a Zn anode is hindered by severe dendrite formation and side reactions. Herein, an interfacial bridged organic–inorganic hybrid protection layer (Nafion‐Zn‐X) is developed by complexing inorganic Zn‐X zeolite nanoparticles with Nafion, which shifts ion transport from channel transport in Nafion to a hopping mechanism in the organic–inorganic interface. This unique organic–inorganic structure is found to effectively suppress dendrite growth and side reactions of the Zn anode. Consequently, the Zn@Nafion‐Zn‐X composite anode delivers high coulombic efficiency (ca. 97 %), deep Zn plating/stripping (10 mAh cm?2), and long cycle life (over 10 000 cycles). By tackling the intrinsic chemical/electrochemical issues, the proposed strategy provides a versatile remedy for the limited cycle life of the Zn anode. 相似文献
14.
15.
Z. Mojović S. Mentus I. Krstić 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2007,81(9):1452-1457
A new type of an electrode material, zeolite modified by the incorporation of Ni or NiO clusters into its cavities, was synthesized
by multiple impregnation of zeolite 13X with a Ni-acetylacetonate solution followed by solvent evaporation and thermal degradation
of the nickel compound. Samples with a Ni/13X mass ratio within the range 0.2–1.0 were synthesized. Modification by both Ni
and NiO clusters, depending on whether the atmosphere was reducing (H2) or oxidizing (air), respectively, was used to finish the sample. After modification, the zeolite kept its original crystallographic
structure, as proven by X-ray diffractommetry. The dimensions of the incorporated clusters were limited by the diameter of
the zeolite cavities (reaching 1.3 nm). This material, homogenized with 10 wt % of nanodispersed carbon, was bonded in the
form of a thin layer to a glassy carbon disc by means of Nafion and used as an electrode material in an aqueous 0.1 M NaOH
solution. The cyclovoltammograms of this thin-layer electrode resemble those of a smooth nickel electrode in alkaline solutions.
The text was submitted by the authors in English. 相似文献
16.
Direct Detection of Supramolecular Reaction Centers in the Methanol‐to‐Olefins Conversion over Zeolite H‐ZSM‐5 by 13C–27Al Solid‐State NMR Spectroscopy 下载免费PDF全文
Dr. Chao Wang Dr. Qiang Wang Prof. Jun Xu Dr. Guodong Qi Pan Gao Weiyu Wang Yunyun Zou Dr. Ningdong Feng Dr. Xiaolong Liu Prof. Feng Deng 《Angewandte Chemie (International ed. in English)》2016,55(7):2507-2511
Hydrocarbon‐pool chemistry is important in methanol to olefins (MTO) conversion on acidic zeolite catalysts. The hydrocarbon‐pool (HP) species, such as methylbenzenes and cyclic carbocations, confined in zeolite channels during the reaction are essential in determining the reaction pathway. Herein, we experimentally demonstrate the formation of supramolecular reaction centers composed of organic hydrocarbon species and the inorganic zeolite framework in H‐ZSM‐5 zeolite by advanced 13C–27Al double‐resonance solid‐state NMR spectroscopy. Methylbenzenes and cyclic carbocations located near Brønsted acid/base sites form the supramolecular reaction centers in the zeolite channel. The internuclear spatial interaction/proximity between the 13C nuclei (associated with HP species) and the 27Al nuclei (associated with Brønsted acid/base sites) determines the reactivity of the HP species. The closer the HP species are to the zeolite framework Al, the higher their reactivity in the MTO reaction. 相似文献
17.
A novel type of organic-inorganic hybrid zeolite with organic lattice (ZOL) is studied in detail by solid-state (13)C magic angle spinning nuclear magnetic resonance (MAS NMR). The (13)C MAS NMR measurements employing several pulse sequences quantitatively demonstrate that methylene groups are really incorporated in the framework, although they are partially cleaved into methyl groups. The organic species in ZOL materials are open for adsorbates, which is evidenced by the (13)C MAS NMR measurements for an n-hexane-adsorbing ZOL material. This finding strongly suggests that organic moieties are incorporated as a zeolite framework, indicating that ZOL is not a physical mixture of a carbon-containing amorphous aggregate and a conventional zeolite but a true organic-inorganic hybrid zeolite. 相似文献
18.
M. C. Campo M. C. Baptista A. M. Ribeiro A. Ferreira J. C. Santos C. Lutz J. M. Loureiro A. E. Rodrigues 《Adsorption》2014,20(1):61-75
A gas phase simulated moving bed technology using improved 13X zeolite beads and isobutane as desorbent is assessed for the separation of propane/propylene. Adsorption equilibrium (via gravimetric method) and dynamics (via breakthrough curves) were determined in order to validate the mathematical model used to describe the adsorption process. Simulation results have shown that it is possible to separate propylene from a mixture with propane using gas phase SMB technology. The results indicate that high purity propylene (99.99 % desorbent free basis) can be recovered up to 99.96 % with a productivity of 17.6 mol kg?1 h?1, with propane being also recovered at high levels (99.98 %) and high purity (99.89 % desorbent free basis). Comparing the SMB simulation results obtained for this new 13X zeolite beads with those obtained with a commercial 13X zeolite characterized elsewhere, it was found that the productivity of the process was raised by 25 %, with half desorbent consumption. 相似文献
19.
Solid-state lithium-air battery represents one of the most promising energy storage systems to simultaneously achieve high energy density, safety, and cost-efficiency. Conventional inorganic solid electrolytes are not suitable for the lithium-air systems due to their spontaneous reactions with lithium and/or air. Meanwhile, the large-scale production of inorganic solid electrolytes at a low cost remains highly challenging to date. Recently, Yu et al. demonstrated that lithium-ion exchanged zeolite X membrane could be employed as the solid electrolyte for lithium-air battery owing to its unique microporous structure and the continuous ion-conduction pathway within a single crystal. Moreover, the lithium-ion exchanged zeolite X offers excellent compatibility with lithium and air and exhibits negligible air permeability. The integrated solid-state lithium-air battery exhibits superior electrochemical stability in ambient air compared to conventional liquid and solid electrolytes. Meanwhile, it offers flexibility, safety and tolerance against abuse. Since zeolites have been widely used in the chemical industry, this work opens up numerous opportunities in energy-related fields. The corresponding research has been published in Nature and can be accessed at https://www.nature.com/articles/s41586-021-03410-9. 相似文献
20.
自粘结低硅铝X型沸石的结构、吸附和N_2/O_2分离比 总被引:2,自引:0,他引:2
用原位合成方法直接将高岭土转化为所需形状的低硅X型沸石(PLSX),经X衍射,~(29)Si,~(27)AI MAS NMR谱证实PLSX的结构硅铝比接近1,它含LSX的组成为40.40%,含4A的组成为17.92%,其余为无定形硅、铝氧化物.LSX的骨架硅铝比接近1,是骨架负电荷分配最均匀的X型沸石,293K时静态法测定和推算ISX的饱和吸附水达39.80wt%,LSX的组成为Na(96-x)K_x(Al_(96)S_i(96)O_(384))·310H_2O,是吸附量高、价廉的吸水剂.PLSX对空气中氮氧的分离系数为α(N_2/O_2)=3.15,高于用于PSA的商品5A的α(N_2/O_2)=2.33和已报道的13X的α(N_2/O_2)=2.36.PLSX也是一种极好的吸附分离剂. 相似文献