含膨润土的部分水解交联聚丙烯酰胺高吸水性树脂的研究

<正> 高吸水性树脂是近年来迅速发展起来的一类新型功能高分子材料,其应用十分广泛,但该类材料尚需急待解决三大问题,即降低成本,提高吸水后凝胶强度,提高凝胶耐盐性,后者已有文献报道,而前两个问题还没有得以解决.作者于1978年曾用丙烯酰胺(AM)和甲叉基双丙烯酰胺碱水溶液共聚交联,水解、造粒、烘干、粉碎,研制出吸水膨胀     

高吸水树脂凝胶强度的测定

高吸水树脂可用于油田调剖堵水,有机溶剂脱水及农田保水等。高吸水树脂凝胶中的水不易挤出。吸水凝胶的强度的岩芯测定法由于所取岩芯孔洞不均,测定结果重现性差。本文介绍一种测定吸水树脂凝胶抗压强度和抗压能的方法。 将凝胶置于压缩器中,用INSTRON-1121型材料试验机测定极限压强,以抗压强度σ表     

聚丙烯酰胺/聚乙烯醇水凝胶的制备及其在海洋在线监测参比电极中的应用

本文采用正交试验设计制备不同配比的聚丙烯酰胺(PAAm)与聚乙烯醇(PVA)交联的水凝胶,并对其吸水和机械性能进行评价,筛选出适合海洋环境要求的吸水性能优异、机械强度好的最优制备条件。依据该条件制备凝胶,装配成参比电极,测试其电极电位的稳定性。结果表明,该参比电极在模拟海水中有很好的电位稳定性,其稳定后电位的漂移值小于0.1mV,PAAm/PVA水凝胶能作为电解质应用于在线监测的参比电极。     

纳米TiO2/聚N-异丙基丙烯酰胺复合水凝胶的合成及其表征

通过利用偶联剂和超声分散将TiO₂表面功能化, 在其表面引入烯键, 与聚N-异丙基丙烯酰胺在交联剂存在下共聚, 制备了不同纳米TiO₂含量的聚N-异丙基丙烯酰胺复合水凝胶．采用红外光谱、扫描电镜、紫外光谱、热重分析、动态粘弹谱仪等表征了复合水凝胶的微观结构和形貌, 测试了复合凝胶材料对紫外线的吸收、热稳定性、机械强度及其韧性. 结果表明: 纳米TiO₂粒子的引入, 使得复合凝胶材料对紫外线吸收效果显著, 凝胶的稳定性、机械强度及韧性得到明显改善.     

UV固化共聚制备含铕(Ⅲ)水凝胶及其荧光行为

以氧化铕(Eu2O3)、邻菲罗啉(phen)和丙烯酸(AA)为原料,制备了含铕(Ⅲ)三元活性配合物(Eu(AA)3phen),将其与丙烯酸-丙烯酰胺凝胶体系进行UV共聚,制备了含铕水凝胶。研究了凝胶中Eu(AA)3phen含量对其吸水性、温敏性及荧光性能的影响,同时探讨了温度及溶胀时间对其荧光性能的影响。结果表明:随Eu(AA)3phen含量的增加,凝胶吸水率先增加后减少,荧光强度逐渐增强;对于特定的凝胶体系,其12 h溶胀度随温度增加而增加,凝胶的荧光强度随溶胀时间和温度增加而减弱。当Eu(AA)3phen的添加量为3.5%时,凝胶综合性能最佳:平衡溶胀度为631 g·g-1,4 h内吸水率达90%以上,荧光强度为175a.u.。所研制的水凝胶在吸水及荧光性能方面对温度均具有良好的响应性。     

辐射交联制备改性CMC水凝胶的溶胀行为研究

利用丙烯酰胺 (AAm)接枝改性纤维素 ,然后进行羧甲基化反应得到高取代度的丙烯酰胺 羧甲基纤维素钠 (AAm CMC Na) .对该材料进行γ射线辐照制备出新型改性CMC水凝胶 .研究了这种水凝胶的溶胀动力学、交联动力学以及温度、pH值和无机盐浓度对水凝胶溶胀行为的影响 ,并与CMC Na水凝胶进行了比较 .结果表明 ,该水凝胶和CMC Na水凝胶相比 ,优点在于辐照交联所用的剂量下降 ,而且所需的CMC浓度减少 .AAm CMC Na水凝胶的溶胀度随温度升高而增大 ,在pH为 6～ 8范围内达到最大值 ,并随无机盐浓度与吸收剂量增加而下降 ,表现出较好的温度敏感性和pH敏感性 ,可望作为吸水材料和水保持剂     

纳米TiO2/聚N-异丙基丙烯酰胺复合水凝胶的合成及其表征

通过利用偶联剂和超声分散将TiO₂表面功能化, 在其表面引入烯键, 与聚N-异丙基丙烯酰胺在交联剂存在下共聚, 制备了不同纳米TiO₂含量的聚N-异丙基丙烯酰胺复合水凝胶．采用红外光谱、扫描电镜、紫外光谱、热重分析、动态粘弹谱仪等表征了复合水凝胶的微观结构和形貌, 测试了复合凝胶材料对紫外线的吸收、热稳定性、机械强度及其韧性. 结果表明: 纳米TiO₂粒子的引入, 使得复合凝胶材料对紫外线吸收效果显著, 凝胶的稳定性、机械强度及韧性得到明显改善.     

腐植酸钠/聚丙烯酰胺/粘土杂化水凝胶的研究

以过硫酸钾为引发剂、N,N′-亚甲基双丙烯酰胺为交联剂、丙烯酰胺单体和腐植酸钠、Laponite RD粘土为原料,用溶液聚合交联法合成了腐植酸钠/聚丙烯酰胺/粘土(SH-PAM-Clay)系列水凝胶.用场发射扫描电镜对其表面形貌进行了研究,并对水凝胶的吸水性和流变性能进行了测试和研究.结果表明这系列水凝胶都具有致密的网络结构和优良的吸水性能.     

快速、高强超吸水凝胶的研究

概括介绍了一些在高吸水凝胶基础上提高凝胶吸水速率和膨胀凝胶强度的方法以及近年来的相关研究状况,展望了制备吸液量大、吸液快且强度高的水凝胶的研究发展前景.     

高吸水性树脂性能缺陷及其改性策略的研究进展

高吸水性树脂凭借其优越的吸水和保水性能,已成为国民经济各个领域中不可或缺的重要材料,但传统的高吸水性树脂吸水速度慢、耐盐性差、凝胶强度低等问题限制了其发展。针对高吸水性树脂日益明显的缺陷,科研人员开始着手研究合成和加工新方法,以降低树脂生产成本低,提高树脂生物降解性、凝胶强度、吸水性和耐盐性等性能,从而推广产品使用范围。本文基于近年来该领域的研究,概括了高吸水性树脂目前主要存在的性能缺陷,并提出相应的改性策略来提高吸水性树脂的综合性能。     

Synthesis and structure features of composite silicate and hybrid TEOS-derived thin films doped by inorganic and organic additives

The results of long-term researches of thin films prepared from tetraethoxysilane-derived sols containing inorganic and organic additives are systematized and analyzed. These additives give to films certain physicochemical properties for their application in electronic techniques, optics, power engineering, in biological technologies etc. The influence both inorganic (salts, acids) and organic (polyols, polyionenes, epoxy resin) additives on rheological properties and aggregate stability of sols as well as films surface morphology is minutely considered. The explanations of phenomena during film formation, including spin-coating process, are given. Essential influence of temperature and humidity on films surface morphology is shown. Influence of heat treatment modes on structure and composition of films is analyzed. Recommendations about optimization of thin films sol–gel processing are offered.     

某些助剂对明胶的凝胶强度的影响的研究

众所周知,物理力学性能是照相明胶的一种很重要的属性。在各种彩色及黑白胶片都面向高温快速加工发展的今天,这种属性就显得更为重要。提高胶片的物理力学性能,一方面要从提高明胶本身的胶冻强度着手,例如减少明胶中溶胶组份(分子量小、冷水中溶解度高),提高明胶中的α和β组份的相对含量,减少分子量过大的组份等等。     

Thermogelation of amphiphilic poly(asparagine) derivatives

Thermoresponsive sol–gel transition polymers based on biodegradable poly(amino acid) were synthesized by the reaction of poly(succinimide) with dodecylamine and amino alcohols. The introduction of the hydrophobic amine into the thermoresponsive poly(amino acid)s induced the sol–gel transition in phosphate buffer saline. The effects of the side chain structure, molecular weight, concentration of the polymer, and the additives (inorganic salts and urea) in the solution on the thermoresponsive behaviors were systematically investigated. A relationship between the lowest critical solution temperature (LCST) in the dilute solution and the viscosity reduction of the concentrated solution upon heating was observed. The present poly(amino acid)s showing a thermoresponsive sol–gel transition in aqueous solutions possess immense potential as an injectable biodegradable hydrogel system for various biomedical applications. Copyright © 2009 John Wiley & Sons, Ltd.     

Photo-fenton degradation of phenol red catalyzed by inorganic additives: A technique for wastewater treatment

Oxidation by photo-Fenton like reaction is an economically feasible process for degradation of a variety of hazardous pollutants in wastewater from dyeing and printing industries. In present study, the progress of the reaction has been monitored spectrophotometrically. An effort has been made to observe the effect of various inorganic additives like sodium thiosulfate and potassium bromate. The effect of variation of different parameters such as pH, concentrations of dye, Fe³⁺ ion and additives, amount of H₂O₂, and light intensity on the rate of photodegradation was also observed. A tentative mechanism for the reaction has been proposed.     

Periodic precipitation of cobalt(II) oxinate in agar gel: factors influencing the flocculation

The influence of concentration, ageing and pH of the gel medium on the periodic precipitation of cobalt oxinate in agar gel is reported. The results are explained on the basis of Shinohara’s revised flocculation theory. The flocculation value (F) increases with increase in the gel concentration whereas it decreases with increase in ageing and pH of the gel. The raise in temperature of the gel increases the solubility of the sparingly soluble substance and hence theF value. The effect of additives on the periodic precipitation of cobalt (II) oxinate is reported.     

成核剂对共聚酯热熔胶结晶动力学的影响

热熔胶因具有粘接迅速、强度高、无毒害、无污染等优良性能而被誉为“绿色胶粘剂”.近十多年来 ,热熔胶在纺织品工业 (如服装工业、粘合衬工业 )领域中已得到了广泛的应用 ,而高质量粘合衬的制造 ,关键在于要有高性能的热熔胶[1] .共聚酰胺和共聚酯热熔胶是两大类性能优良的粘合衬用热熔胶 ,由于共聚酯类热熔胶在手感、价格以及耐水洗、砂洗和蒸汽压烫等方面优于共聚酰胺热熔胶 ,而有着更为广阔的发展前景 .但结晶速率缓慢一直是共聚酯尚未解决的一个技术难题 .本文主要研究了成核剂对共聚酯热熔胶结晶速率的促进作用 ,并取得了较为理想的结…     

Effect of inorganic salt on the dose sensitivity of polymer gel dosimeter

The effect of inorganic salts, non-transition metal chlorides, on the dose sensitivity of methacrylic-acid-based polymer gel dosimeter is investigated. Dose-R₂ responses are obtained from magnetic resonance imaging data. Temperature increase due to exothermic polymerization reaction in the gel is also measured directly during irradiation. As a result, substantial increases in R₂ response are observed in the polymer gel dosimeter containing inorganic salt, especially with MgCl₂. The sensitivity of the gel with 1.0 M MgCl₂ is approximately 2.8 times higher than that of without MgCl₂. As the salt concentration increases, an increase of polymerization rate is also observed via the temperature measurements. These results indicate that inorganic salt acts as an accelerator for radiation-induced free-radical polymerization in methacrylic-acid-based gel.     

无机添加剂对硝酸铵拒爆性的影响研究

考察了无机添加剂对农用硝酸铵拒爆性的影响。结果表明，当硝酸铵中添加3%的无机改性剂GXJ 1和10%的无机改性剂GXJ 2后，其拒爆性能明显增强；改性后的硝酸铵按照工业炸药配方配制成铵油炸药，不能被8号雷管起爆。而且改性后的硝酸铵颗粒强度高，不易粉化、结块和吸潮，具有优良的肥料品质。经济效益分析也表明，改性硝酸铵具有广阔的市场应用前景。通过X射线衍射分析、扫描电子显微镜分析等对改性硝酸铵进行了表征，并对拒爆机理进行了初步探讨。     

Assessing the synergy effect of additive and matrix on single-crystal growth: Morphological revolution resulted from gel-mediated enhancement on CIT-calcite interaction

CIT additives are active in crystal morphology modification at relatively high concentration. Once agarose gel is simultaneously introduced, the curved morphological feature of calcite crystal emerges at a much lower concentration of CIT additives.     

聚酰亚胺纳米杂化材料的制备、结构和性能

介绍了聚酰亚胺（PI）纳米杂化材料的四种制备方法：溶胶－凝胶法、插层法、分散法、相转移分散聚合法。纳米粒子在PI材料中分散性良好。由于纳米粒子本身 性和纳米粒子改变了PI材料的应力作用点，随着SiO2,AIN等纳米粒子含量增加，PI杂化的玻璃化温度、热分解湿度、拉伸强度、断裂伸长率、杨式模量、密度增加，线性膨胀系数减少。对介电性能的影响因不同纳米材料而异。