水中矿化度对复合吸水材料吸水膨胀的影响

以吸水倍率为指标,研究了水中矿化度对具有互传网络结构的复合吸水材料吸水膨胀的影响。结果表明,在研究范围内,水中矿化度越高,外界电解质溶液中可动离子的浓度增加,材料内部与水体中离子浓度差降低,作为吸水膨胀动力的渗透压减弱,吸水倍率下降;阳离子对材料吸水膨胀的影响显著,碱土金属离子(二价)可以与吸水聚合物网络上的阴离子反应,因此对吸水膨胀的影响远大于碱金属离子(一价),同族阳离子对吸水膨胀的影响相差不大;同族阴离子对吸水膨胀的抑制作用相当,二价阴离子由于电离等因素,对复合吸水材料吸水膨胀的影响存在差异。     

遇水膨胀聚氨酯弹性体的制备与膨胀性能研究

以聚乙二醇、聚四氢呋喃二醇、甲苯二异氰酸酯为原料,用预聚体法制备出遇水膨胀聚氨酯弹性体,研究了聚乙二醇用量和种类对聚氨酯的力学性能及其在不同矿化度水中的吸水膨胀性能的影响。实验结果表明:增加聚乙二醇用量有利于提高聚氨酯的吸水膨胀倍率,但易降低弹性体的力学性能;矿化度对聚乙二醇型聚氨酯的吸水膨胀倍率影响较吸水树脂复合型遇水膨胀橡胶要小得多。     

超吸水纤维吸水倍率的测试方法研究

以超吸水纤维吸水倍率测试的企业标准为基础,分析超吸水纤维吸水倍率的影响因素。结果表明：超吸水纤维的吸水倍率测试受非织造布布袋尺寸、水温、离子浓度、pH值、浸泡时间、切断长度的影响较大,受水体积的影响较小。据此提出了适合超吸水纤维吸水倍率的测试方法。     

SLs-AA型高吸水性树脂的应用性能研究

制备SLs-AA型高吸水性树脂,研究了外部溶液中离子种类与浓度及不同pH值的溶液对该树脂吸水倍率的影响,分析不同粒径吸水性该树脂的吸水倍率随时间的变化和该树脂在土壤中的抑制蒸发情况,并在分析过程中讨论SLs-AA型高吸水性树脂吸水机理。     

吸水膨胀橡胶的研究进展

介绍了吸水膨胀橡胶的吸水膨胀机理、基体材料选择、制备工艺以及近年来的研究发展概况,并对吸水膨胀橡胶制备中存在的问题进行总结。吸水膨胀橡胶主要由橡胶基体和亲水组分组成,采用物理共混和化学接枝的方法制备,吸水后亲水组分析出、吸水膨胀倍率和吸水膨胀速率的选择、橡胶交联密度与吸水倍率的平衡等问题是吸水膨胀橡胶在实际应用中普遍存在的问题,需重点研究。     

原位聚合丙烯酸锂制备吸水膨胀丁腈橡胶的性能研究

以丁腈橡胶为基体,加入丙烯酸锂(LiAA)和过氧化二异丙苯(DCP)通过原位聚合制得吸水膨胀橡胶,研究了其力学性能和吸水性能。结果表明:LiAA在DCP引发作用下在NBR橡胶中发生原位聚合。随着三烯丙基异三聚氰酸酯(TAIC)用量的增加,WSR的拉伸强度和吸水膨胀倍率先增加后降低。在盐溶液中WSR的吸水能力有明显的降低,其中二价钙离子影响最为明显。WSR的吸水能力随着溶液pH的增加,先上升后降低,在pH为8时,吸水平衡倍率最大。加入白炭黑能够显著提高WSR的力学性能,而加入PEG则提高WSR的吸水速率。     

耐超高矿化度遇水膨胀橡胶的制备及性能

用甲基丙烯酸羟乙酯(HEMA)对吸水膨胀聚氨酯(PU)预聚体进行封端,制备出PU聚合物活性树脂。以丁腈橡胶(NBR)为基体,将聚丙烯酰胺(PAM)树脂和PU聚合物活性树脂共混,实现PU聚合物活性树脂与NBR大分子化学接枝交联,制备出新型高耐盐型遇水膨胀橡胶(WSR)。研究了超高矿化度下,PAM用量对材料力学性能和吸水膨胀倍率的影响。结果表明,PAM用量增加,WSR吸水膨胀倍率提高,但是力学性能降低;在20万超高矿化度下,浸泡400h后,WSR最大膨胀倍率稳定在2.7倍左右,表面无析出现象,表现出优异的耐盐性。     

交联型吸水膨胀天然橡胶的吸水性能

以天然胶乳为原料,丙烯酰胺为吸水单体,通过接枝共聚反应制得吸水膨胀天然橡胶(WSNR)。分别以甲醛为单体交联剂,硫磺为天然橡胶交联剂,经过接枝共聚反应制备单体交联型吸水膨胀天然橡胶(WSNR-c)和橡胶硫化交联型吸水膨胀天然橡胶(WSNR-v)。研究了不同交联方式对吸水膨胀橡胶吸水倍率、重复吸水能力和弹性模量的影响,并对吸水膨胀天然橡胶中水的状态、热失重过程和微观形貌进行分析。结果表明：吸水膨胀天然橡胶的吸水倍率、重复吸水恢复率和储能模量随着吸水单体和天然橡胶交联程度的提高而降低;交联处理使吸水膨胀天然橡胶吸束缚水的能力减弱,失水稳定性降低;吸水膨胀天然橡胶经交联处理后体系网络结构致密,孔洞减少。     

木质素基吸水树脂的制备及性能研究

将烯丙基缩水甘油醚与丙烯酰胺共聚合成带环氧基的亲水高分子,并利用其共交联木质素制备木质素基吸水树脂,考察了木质素用量、丙烯酰胺与烯丙基缩水甘油醚的配比、pH等对树脂吸水性能的影响。结果表明,木质素基吸水树脂具有pH敏感性,吸水倍率随pH增加而增大;吸水树脂的吸水率随着木质素用量的增加而降低,增加烯丙基缩水甘油醚用量,吸水树脂的交联密度增加,其吸水率降低。当木质素用量为5 g,丙烯酰与烯丙基缩水甘油醚的配比为0.06∶0.03时,制备的木质素基吸水树脂在pH=9的水溶液中吸水倍率为36.3 g/g。     

壳聚糖接枝聚丙烯酸钠/高岭土复合树脂的吸水性能

利用溶液聚合法制备了壳聚糖接枝聚丙烯酸钠/高岭土复合树脂,研究了复合树脂在蒸馏水中的吸水速率、重复吸水性能和人工尿液中的吸水倍率,以及在不同温度、不同电解质溶液离子强度和不同pH值的环境下复合树脂的吸水性能。结果表明,复合树脂的吸水速率较慢,在多次重复吸水后吸水性能也逐渐降低,在人工尿液中的吸水倍率高于聚丙烯酸钠树脂,低于壳聚糖接枝丙烯酸钠树脂;随着温度的升高,复合树脂的吸水能力增强,超过50℃后变化较小;树脂的吸液倍率随着电解质溶液浓度和价态的增大而下降;随着pH值的增大而出现驼峰,在pH=3.5和pH=8.5处分别出现吸液倍率最大值。     

Synthesis and swelling behavior of pH- and temperature-sensitive poly[2-(dimethylamino)ethyl methacrylate-co-2-acrylamido-2-methylpropane-1-sulfonic acid] hydrogels

Summary Poly[2-(dimethylamino)ethyl methacrylate-co-2-acrylamido-2-methylpropane-1-sulfonic acid], poly(DMAEMA-co-AMPS), hydrogels were prepared by chain polymerization in water at 60 °C in the presence of tetraethyleneglycol diacrylate (TEGDA) as crosslinking agent. Ammonium persulfate (APS) and N,N,N’,N’-tetramethylethylenediamine (TEMED) were used as initiator and accelerator, respectively. Hydrogels with different feed compositions were prepared by keeping the total monomer concentration constant at 1 or 0.5 M. The concentration of TEGDA in the feed was adjusted so that it made for 3 or 2 mol % of the total monomer content while it was 1% for APS. In order to observe the effects of pH and ionic strength of the medium on swelling, the equilibrium swelling behavior of these hydrogels were investigated both in distilled water at various temperatures between 30 and 90 °C and in different buffer solutions with pH of 2.8, 5.3, 7.0, 10.0, and 12.4 at constant ionic strength (I=0.08 mol/l) at room temperature. The effects of temperature and co-monomer AMPS content on the swelling behavior of poly(DMAEMA-co-AMPS) in distilled water were also investigated. The copolymers with equimolar contents of DMAEMA and AMPS displayed minimum swelling both in distilled water and in buffer solutions due to ionic complex formation. Their swelling values in distilled water between 30 and 90 °C were constant. While equilibrium swelling values of copolymers in buffer solutions with pH between 2.8 and 7 were almost constant, they increased with increasing pH. The increase in the AMPS content and decrease in initial monomer concentration increased the equilibrium swelling values of copolymers.     

海水淡化水矿化过程研究

利用硫酸溶解石灰石对淡化海水进行矿化处理,研究了pH值、石灰石颗粒粒径和装填高度、淡水流量及反应温度等因素对淡化水矿化效果的影响。试验发现pH值变化对矿化效果的影响最为明显。在一定的填料高度范围内,矿化效果随pH值降低增加显著,随填料高度的增加而增加,随淡水流量的增加而降低,随着温度的升高而升高。在pH值为2.00的实验条件下,矿化后钙离子含量大于300 mg/L。     

具有pH及温度敏感性的共聚物Poly(NIPAm-co-IA)水凝胶的合成及其性能研究

用自由基聚合合成了具有两水亲性的异丙基丙烯酰胺与衣康酸共聚物 ,对它们水溶液及其水凝胶的 p H及温敏性进行了研究。结果表明 ,在一定的范围内 ,随衣康酸含量增加、水溶液浓度减少和 p H值增大 ,共聚物水溶液的低临界溶解温度随之升高。共聚物水凝胶的溶胀率随温度升高呈下降趋势 ,并且 p H值低时的溶胀率随温度的升高而下降的趋势比 p H高时的要快 ,而且表现出明显的溶胀 -退胀可逆过程。     

Synthesis and characterization of pH- and/or temperature-sensitive hydrogels

A series of pH-sensitive hydrogels that exhibit volume phase transition phenomena have been synthesized in aqueous solution and characterized with respect to their dynamic swelling behaviors. Positively charged hydrogels were prepared by copolymerizing varying ratios of N-isopropylacrylamide and NN′-dimethylaminopropylmethacrylamide. The hydrogels based on a temperature-sensitive hydrogel demonstrate a large change of equilibrium swelling in response to small variations of pH and/or temperature. These hydrogels exhibit different lower critical solution temperature (LCST) ranges depending on the environmental pH values. Below their LCST, they exhibit small and broad pH sensitivities normally observed in most hydrophilic polyelectrolyte gels, but above their LCST, they exhibit sharp pH dependent phase transition behaviors. The pH-dependent phase transition is strongly affected by temperature, while the temperature-dependent transition is, in turn, largely influenced by the pH. As the temperature is raised, the transitional degree of gel swelling change becomes sharper and larger, and the phase transition pH value shifts to a lower pH. It was also found that swelling is faster than deswelling for these cationic hydrogels, which suggests the existence of a water diffusion barrier during the deswelling. The swelling kinetics of initially dry and glassy gels were strongly dependent on both the pH value and temperature.     

Studies on Swelling Behavior of Wood-Polymer Composites Based on Agro-Waste and Hdpe in Steam and Water at Ambient Temperature

The polymer composites of HDPE and banana, hemp, and agave fibers (50 : 50, w/w) were prepared separately with and without treatment of maleic anhydride. The swelling phenomenon in terms of absorption of water and steam was studied and it was found that the steam penetrates more within a smaller period of time than the water at ambient temperature. The maleic anhydride treatment on these fibers showed the ester-ification of fibers, and because of that, the absorption (swelling) of steam and water is less than the untreated respective fibers composites.     

吸水膨胀型聚合物堵漏剂的合成与评价

研制了一种吸水膨胀聚合物堵漏剂,该堵剂由丙烯酸（AA）、丙烯酰胺（AM）、膨润土、N,N-亚甲基双丙烯酰胺通过溶液自由基聚合法合成。并通过实验探讨了交联剂用量、引发剂用量等因素对此聚合物堵漏剂的性能的影响,获得了适宜的制备条件为：引发剂用量0.35%;m（AA）：m（AM）=3：1;单体浓度30%;膨润土加入量15%;交联剂用量0.06%;体系pH值7.0;反应温度50℃。再采用正交实验法对聚合物配方进行了优选。并将优选出的几组配方进行堵漏评价,实验结果表明,该吸水膨胀聚合物具有堵漏性能,且该聚合物具有吸液倍数大、耐盐性好、吸水后凝胶强度较好的等特点。     

奈曼油田低渗透储层潜在伤害因素分析

通过对奈曼油田注入水各项流体的配伍指标的筛选、敏感性评价结果表明：该区储集层呈弱速敏、强水敏、弱盐敏。据此提出储集层保护措施为：钻井、试油、洗井时入井液的矿化度在2 500 mg/以上,考虑悬浮物浓度在1 mg/L,颗粒最大直径确定为≯1.2μm,以〈0.6μm为宜,含油量为2.5 mg/L;建议在注水开发时注入液中加入一些防膨剂,抑制粘土的膨胀性。     

Influence of temperature on the hydro-mechanical behaviour of a compacted bentonite

This paper reports the results on the influence of temperature (between 20 and 80 °C) on some hydro-mechanical properties of a compacted bentonite. The water retention capacity at higher temperature, both in confined and unconfined conditions, is lower, especially when suction is low. At high temperatures, the swelling capacity of clay decreases, although the influence of temperature is less evident when the applied stress is high. Furthermore, a decrease in swelling pressure as a function of temperature was observed. On the other hand, the measured increase in permeability with temperature is lower than expected on the basis of thermal change in water kinematic viscosity. The transfer induced by temperature between intra-aggregate adsorbed water and inter-aggregate free water may explain most of the features observed, taking into account that the physical characteristics (density, viscosity) of water in each one of these two states are different.