多孔粘土复合材料的孔结构和孔径分布

采用低温氮吸附法研究了多孔粘土复合材料的孔径分布和孔结构,讨论了不同交联物对材料孔结构和孔径分布的影响,结果表明,材料合成条件特别是交联物的水解过程对多孔粘土的孔结构和孔径分布有十分重要的影响。      

含钛多孔粘土材料的合成与表征

采用ｓｏｌ－ｇｅｌ法合成了含Ｔｉ多孔粘土材料,并利用ＸＲＤ、ＩＲ、ＤＴＡ等方法对其实验条件进行初步探讨．结果表明,ｓｏｌ－ｇｅｌ法比ＴｉＣｌ_４水解法更容易形成大孔结构,在［Ｔｉ］＝０．８２ｍｏｌ·Ｌ^－１、［Ｔｉ］／±＝２０ｍｍｏｌ·ｇ^－１的条件下,可得到层间开孔达２．９３ｕｍ、比表面３５１．０ｍ~２·ｇ^－１的含Ｔｉ多孔粘土材料,材料在８６０℃之前具有较好的热稳定性．     

新型生物降解交联剂的制备和交联壳聚糖的性能

制备异氰酸酯基封端的一系列生物降解型交联剂,研究了反应条件对产物的影响.进一步使用此生物降解交联剂制备了交联壳聚糖多孔材料,研究了所得材料的性能.结果表明,当反应温度为70℃,反应时间为3h,投料比为2.2:1时,交联剂中NCO的质量分数为4.64%,浓度为50%的THF溶液粘度为500MPa·s,其性能适宜交联壳聚糖.随着-NCO/-NH2摩尔比的增加,交联壳聚糖多孔材料表面形貌呈现出从开孔结构逐渐过渡为闭孔结构的状态,保水率基本为未交联材料的3倍,其最大拉伸强度和弹性模量均有较大提高,最大为0.17 GPa和1.4 GPa.新型交联剂由于具有可降解的PEG-b-PLA链段,不仅保证了交联壳聚糖的降解性能,改善其亲水性,也提高了材料的力学性能.     

交联粘土催化剂的结构,性质和应用

交联粘土是当今备受瞩目的催化材料，在石油加工、精细化工以及环境科学领域有十分广阔的应用前景。介绍了交联粘土的制备、结构、性质和应用，评述了有关方面的最新进展。     

浓乳液法制备聚丙烯腈多孔材料的研究

采用浓乳液法制备了聚丙烯腈多孔材料,研究了交联单体的含量、SiO_2浓度和分散相的体积分率等因素对聚丙烯腈多孔材料结构的影响,并使用扫描电镜及氮气等温吸附等手段对材料的结构进行了表征。结果表明,在浓乳液中,纳米SiO_2粒子会吸附在乳液的界面上起到共乳化剂的作用,阻止乳液中分散相液滴的聚集,从而能够有效地提高乳液的稳定性;通过调节浓乳液的组成,如分散相的体积分率、SiO_2和交联剂的浓度等参数可以有效地控制聚丙烯腈多孔材料的孔结构。     

粘土/聚丙烯酰胺系高吸水性复合材料的研究

采用水溶液聚合法 ,以硝酸铈铵为引发剂 ,N ,N -亚甲基双丙烯酰胺为交联剂 ,在淀粉接枝共聚丙烯酰胺的基础上添加矿物粉体 ,合成高吸水性复合材料。本文系统地研究了淀粉、交联剂、引发剂、粘土、水解度等聚合条件对复合材料吸水性能的影响 ,制备出的粘土 /有机树脂复合材料具有较高的吸水性及保水性 ,在降低产品生产成本及提高材料综合性能方面具有使用价值。其吸蒸馏水及 0 9%NaCl溶液分别为 30 10 g g- 1和 138g g- 1。     

交联聚合物溶液封堵多孔介质机理研究

交联聚合物溶液是由低浓度部分水解聚丙烯酰胺(HPAM)和交联剂柠檬酸铝(AlCit)形成的交联聚合物线团在水中的分散体.采用毛玻璃模型和并联岩心实验对交联聚合物溶液的封堵机理进行了研究.结果表明,交联聚合物溶液的封堵性能与多孔介质表面的特性是密切相关的,交联聚合物线团与水润湿多孔介质表面的相互作用力较强,易于在多孔介质喉道处吸附、滞留、聚集,形成较高强度封堵;对于油润湿多孔介质,交联聚合物线团难以在喉道处滞留形成封堵; 交联聚合物溶液在驱替过程中,聚合物、柠檬酸铝和交联聚合物线团的吸附都不是平衡吸附,在近井地带的吸附滞留量小于远井地带,产生架桥封堵的可能小,因此交联聚合物溶液能够深入地层深部产生深部调剖效果.     

腐植酸-粘土高吸水性树脂的制备研究

以丙烯酸为单体,采用溶液聚合与腐殖酸钠、粘土进行反应合成新型腐植酸高吸水树脂GHA.采用正交试验系统地考察了引发剂、交联剂、粘土及AA/HA对吸水树脂吸水倍率的影响.结果表明当引发剂0.3％、交联剂0.1％、粘土20％和AA/HA为4∶1时,产物的吸蒸馏水倍率最大;当引发剂0.3％、交联剂0.1％、粘土20％和AA/HA为4:1时,产物的吸蒸馏水速率达到361g/g,吸盐水倍率为86g/g,吸水后凝胶强度高.     

矿物基多孔材料的制备及其吸附研究进展

从矿物基多孔材料的制备工艺、检测方法、工艺参数的控制及应用方面综述了粘土矿物的颗粒化技术研究进展,探讨了各因素对制备过程的影响,并讨论了矿物粘土颗粒吸附剂的吸附机理,最后提出矿物粘土颗粒化技术在今后研究中需加强的方面。     

组织工程海藻酸钙多孔支架的制备和研究

采用浇铸/冷冻干燥的方法制备出一种可组装于神经导管内的组织工程海藻酸钙多孔支架.通过IR、SEM、不同浓度交联剂对凝胶化过程的平衡溶胀比、抗压强度以及多孔支架在SBF液中的含水率和体积膨胀度的分析,对7海藻酸钙多孔支架的性能进行了讨论.结果表明,海藻酸钠多孔支架在氯化钙溶液浸渍中能快速反应生成海藻酸钙,并在凝胶化反应过程中可保持原有呈一定方向排列、孔隙连通和层状的多孔结构;多孔支架随交联剂中Ca2+浓度的增加,形成的海藻酸钙多孔支架的抗压强度提高,使支架的稳定性增加;海藻酸钙多孔支架在SBF中的含水率>90%,体积的膨胀度与交联剂中Ca2+浓度成反比.     

Preparation and characterization of safe microparticles based on xylan

This work describes the preparation and evaluation of safe xylan-based microparticles prepared by cross-linking polymerization using sodium trimetaphosphate. The resulting microparticles were evaluated for morphology, particle size, polymer-cross-link agent interaction, and in vitro toxicity. The microparticles showed narrow monodisperse size distributions with their mean sizes being between 3.5 and 12.5?µm in dried state. FT-IR analyzes confirmed the interaction between sodium trimetaphosphate and xylan during the cross-linking process with formation of phosphate ester bonds. Additionally, the X-ray diffraction patterns and FT-IR analyzes suggested that little or no cross-linking agent remained inside the microparticles. Furthermore, the in-vitro studies using Artemia salina and human erythrocytes revealed that the microparticles are not toxic. Therefore, the overall results suggest that these xylan microparticles can be used as a platform for new drug delivery system.     

铬簇合物及铬铝交联蒙脱石纳米复合材料的形成

利用XRD、IR、DTA、比表面和吸氨量等方法研究2:1型的蒙脱石粘土矿物和铬簇合物[Cr₃O(OOCCH₃)₆(OH₂)₃]Cl·6H₂O(简记为CrC)交联剂的层间交联作用,并对铬铝交联蒙脱石纳米复合材料的制备方法、影响因素和性质作初步探讨.结果表明,交联剂分子种类、大小和Cr/Al比值对材料的层间距大小有十分重要的影响;而材料层间距大小、交联剂CrC/土的比例和Cr/Al比值则是影响材料的表面性质和热稳定性的重要因素.     

交联剂对可膨胀小球制备的影响

以丙烯腈为主要单体,以氢氧化镁为无机分散剂,采用常压聚合法,制备了膨胀倍率达到20-30倍的可膨胀小球。系统研究了二丙二醇二丙烯酸酯(DPGDA)、三缩丙二醇二丙烯酸酯(TPGDA)、新戊二醇二丙烯酸酯(NPGDA)、三羟甲基丙烷三丙烯酸酯(TMPTA)和二乙烯基苯(DVB)等5种交联单体对可膨胀小球制备的影响。通过扫描电子显微镜、热重分析、交联密度测定等手段研究了可膨胀小球的形貌、粒径、发泡剂的含量、交联密度、发泡倍率。确定DPGDA为最佳的交联剂种类,用量为1.7%。采用DPGDA作为交联剂的小球既具有较完好的球状形貌,又有较小的粒径,较高的发泡剂含量和较高的交联度,膨胀倍率可达30倍。     

Evaluation of cross-linked chitosan microparticles containing metronidazole for periodontitis treatment

The aims of this study were to find the optimal formulation for the preparation of metronidazole-loaded chitosan microparticles (MTZ-MPs) via an emulsion cross-linking process, and to compare the in vitro release of MTZ from hydrogels and films containing the drug in forms of MTZ-MPs and raw powders. The effects of emulsifier type and concentration, amount of cross-linking agent, cross-linking time, drug:chitosan ratio, form of drug adding and washing method on the properties of the MTZ-MPs were investigated. The results indicated that the optimal conditions for round and free-flowing MTZ-MPs with a high percentage of entrapped drug and preferable release profile were 1% of Span80 in soybean oil, 5% of glutaraldehyde based on chitosan solution, 30 min of cross-linking time, 1:1 drug:chitosan ratio, drug adding in form of ethanol solution and washing with hexane only. MTZ-MPs prepared from the optimal formulation were incorporated in mucoadhesive hydrogel and film. The release profiles of the drug from hydrogel and film containing MTZ-MPs were in prolong pattern compared with those containing drug powders. However, the hydrogels exhibited higher preferable pattern of release profile than the films. Therefore, the hydrogel containing MTZ-MPs was possible to be further clinically investigated for peridontitis treatment.     

温度/pH敏感性壳聚糖-聚乙烯吡咯烷酮水凝胶的制备

以壳聚糖（CS）和聚乙烯基吡咯烷酮（PVP）为原料,戊二醛为交联剂,硝酸铈铵为引发剂,制备了具有温度和pH双重敏感性的CS/PVP水凝胶。考察了制备条件对水凝胶溶胀率的影响,结果表明,在PVP∶CS（质量比）=10∶1,0.3%（质量分数,下同）交联剂（相对于PVP）,2.5%引发剂,60℃反应10 h的条件下,获得的...     

戊二醛改性壳聚糖/ 纳米TiO2 复合膜的抗水性研究

采用戊二醛作为交联剂与壳聚糖进行交联,以提高壳聚糖/ 纳米TiO2 膜的抗水性。采用三元二次通用旋转组合设计实验方法,建立了力学性能、吸水率与戊二醛用量、交联时间、TiO2 溶胶添加量的二次回归数学模型,得出了制备戊二醛改性壳聚糖/ 纳米TiO2 膜的最佳工艺条件为交联剂用量0. 10 g/ (100 mL)乙酸溶液,交联时间4. 37 h,TiO2 溶胶添加量0. 08 mL/ (100 mL)的乙酸溶液。上述条件下得到的膜的拉伸强度为5. 69MPa,吸水率为133. 66%。与壳聚糖/ 纳米TiO2 膜相比,吸水率下降了72. 8%。     

Synthesis and characterization of gelatin nanoparticles using CDI/NHS as a non-toxic cross-linking system

Gelatin nanoparticles, cross-linked by a mixture of a water soluble carbodiimide (CDI) and N-hydroxysuccinimide (NHS) as a non-toxic cross-linking system, was prepared. The conventional two step desolvation method with acetone as the non-solvent was used. The mean size and size distribution as well as the morphology of the formed nanoparticles were evaluated and compared with those of nanoparticles cross-linked by glutaraldehyde (GA) as the most commonly used cross-linking agent. Furthermore, intrinsic viscosities of the nanoparticles cross-linked by CDI/NHS and GA were measured and compared under various conditions. The results showed the formation of smoother and more homogeneous nanoparticles with smaller size when CDI/NHS used as cross-linking agent under the same synthesis condition. Moreover, nanoparticles encapsulating paracetamol as a model drug were produced by the two different cross-linking agents and were characterized for drug entrapment and loading efficiencies and in vitro drug release. Both drug entrapment and loading efficiencies was higher in the CDI/NHS cross-linked nanoparticles; however, the release kinetics was comparable to that of nanoparticles cross-linked with GA. The differences in the characteristics of CDI/NHS and GA cross-linked nanoparticles were attributed to the different nature of network structures formed by the two cross-linking agents. On the whole, these results suggested that CDI/NHS cross-linked nanoparticles have high potential to be used for drug delivery application in preference to the nanoparticles synthesized by toxic cross-linking agents.     

Preparation and study of aramid/epoxy prepregs

Solid epoxy resin compounds were studied for their suitability as matrices for the preparation and curing of prepregs containing aramid fibres. Acid anhydrides were shown to be incompatible to the epoxy resin, producing a dispersed crystalline phase upon drying, whereas o-phenylenediamine is a miscible cross-linking agent. Also, diamine is safer because it reacts with the epoxy at temperatures considerably higher than the anhydrides. Composite specimens prepared by these prepregs display similar tensile strength and lower modulus than those derived from the one-step process, by the use of conventional liquid epoxy systems.     

环氧/粘土纳米复合材料插层/解离行为的研究进展

从环氧树脂/粘土纳米复合材料的结构类型、制备方法以及影响粘土在环氧树脂中插层/解离的因素(烷基铵改性剂、粘土特性、固化剂、固化工艺)、粘土插层/解离的热力学和动力学等方面对环氧树脂基纳米复合材料的研究进展进行了较为深入而详尽的综述.