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4种保水剂吸水和保水性能的差异性研究 总被引:1,自引:0,他引:1
通过室内实验,对比研究了四种保水剂的吸水、保水性能。测试吸水倍率、吸水速率、保水能力及有效持续性等指标,采用评分法对四种保水剂进行综合评价。结果表明:保水剂的吸水倍率与所吸溶液的性质有很大关系。4种保水剂在去离子水中的吸水倍率最高,随着溶液中离子浓度的增大吸水倍率逐渐减小。保水剂颗粒大小对吸水速率有较大影响,对其他指标影响均不大;4种保水剂均具有较强的反复吸水能力。综合分析认为,4种保水剂中,吸水保水性能最优的保水剂为4#保水剂,其成分为聚丙烯酸盐和聚丙烯酰胺共聚体。其次为3#保水剂,再次为1#保水剂,最差的是2#保水剂。 相似文献
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利用双锥法研究了油田现场用超高分子量部分水解聚丙烯酰胺(PHPAM)和疏水改性聚丙烯酰胺(HMPAM)溶液与航空煤油间的界面剪切流变性质,考察了时间、应变幅度和剪切频率对不同浓度PHPAM和HMPAM溶液界面剪切流变参数的影响.结果表明,只有在适宜的剪切频率条件下,流变数据才能反映界面膜的结构信息.HMPAM分子具有界面活性,能吸附在界面上,其界面膜的强度随时间变化逐渐增强,且在高浓度时以黏性为主;PHPAM分子不具有界面活性,其剪切流变参数没有时间依赖性,界面层以弹性为主.HMPAM能通过疏水作用形成界面网络结构,界面膜的剪切复合模量明显高于PHPAM界面层.HMPAM界面层中网络结构在剪切形变作用下的破坏与重组这一慢弛豫过程是其强度较高的原因. 相似文献
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以过硫酸铵(APS)为引发剂,N,N′-亚甲基双丙烯酰胺(MBA)为交联剂,采用水溶液聚合法制备了碳纳米管/聚丙烯酸钠高吸水树脂。系统考察了碳纳米管质量分数、引发剂、交联剂和聚合温度对树脂吸水性能的影响。结果表明,以单体丙烯酸质量为基准,当交联剂,引发剂和碳纳米管质量分数分别为0.04%、0.3%和0.3%,聚合温度75℃时,所合成树脂的吸水性能最佳。添加碳纳米管后树脂表面粗糙和形成孔结构导致了其吸水性能的变化,使得碳纳米管/聚丙烯酸钠的吸水量和吸水速率明显提高,其吸去离子水和生理盐水能力分别达到1423和104g/g。该树脂重复吸水5次后,其吸水能力为1081.5g/g,达到最大吸水倍数的76.0%。 相似文献
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表面活性剂对驱油聚合物界面剪切流变性质的影响 总被引:1,自引:0,他引:1
利用双锥法研究了表面活性剂十二烷基苯磺酸钠(SDBS)和十六烷基三甲基溴化铵(CTAB)对油田现场用部分水解聚丙烯酰胺(PHPAM)和疏水改性聚丙烯酰胺(HMPAM)溶液的界面剪切流变性质的影响,实验结果表明:HMPAM分子通过疏水作用形成界面网络结构,界面剪切复合模量明显高于PHPAM.SDBS和CTAB通过疏水相互作用与HMPAM分子中的疏水嵌段形成聚集体,破坏界面网络结构,剪切模量随表面活性剂浓度增大明显降低.同时,界面膜从粘性膜向弹性膜转变.低SDBS浓度时,少量SDBS分子与PHPAM形成混合吸附膜,界面膜强度略有升高;SDBS浓度较高时,界面层中PHPAM分子被顶替,吸附膜强度开始减弱.阳离子表面活性剂CTAB通过静电相互作用中和PHPAM分子的负电性,造成聚合物链的部分卷曲,从而降低界面膜强度.弛豫实验结果证实了表面活性剂破坏HMPAM网络结构的机理. 相似文献
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部分水解聚(丙烯酸甲酯-乙酸乙烯酯-甲基丙烯酸甲酯)高吸水性树脂的合成及结构研究 总被引:4,自引:0,他引:4
研究了部分水解聚(丙烯酸甲酯-乙酸乙烯酯-甲基丙烯酸甲酯)高吸水性树脂-HP(MA-VAc-MMA)的合成,讨论了聚合,水解工艺条件对该树脂吸水(液)性能的影响,用红外,X-射线衍射和电子衍射等方法测定了共聚物的结构。结果表明,HP(MA-VAc-MMA)树脂的吸水能力为:去离子水837ml/g、自来水440ml/g、0.9%NaCl溶液ml/g、合成血119ml/g、合成尿73ml/g;该树脂具有结晶结构,与PVC树脂共混可制备吸水膨胀性材料。 相似文献
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后交联法合成高吸水性树脂 总被引:1,自引:0,他引:1
以过硫酸钾为引发剂,水为分散介质,丙烯酸钠(AANa)与甲基丙烯酸缩水甘油酯(GMA)共聚得到共聚物P(AANa-GMA),然后用乙二胺(EDA)使氧杂环开环发生交联反应,制得高吸水性树脂。其结构经^1H NMR和IR表征。用茶袋法研究了EDA用量对树脂吸水能力的影响。结果表明,当n(EDA):n(GMA)=1.0:1.4时,树脂的吸水倍率达527倍。 相似文献
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耐水解高吸水树脂的合成与性能研究 总被引:1,自引:0,他引:1
采用2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酸(AA)、十二烷基苯磺酸钠(LAS)为主要原料,以二乙烯基苯(DVB)为交联剂制备出P(AMPS+AA)高吸水膨胀树脂,考察了AMPS与AA配比、中和度、交联剂种类与用量、LAS加量等合成工艺对吸水树脂性能的影响。研究结果表明,在丙烯酸系吸水树脂中引入AMPS结构单元,有利于提高树脂在盐水中的吸液能力,改善高吸水树脂的耐盐性;在以DVB为交联剂制备P(AMPS+AA)树脂时,LAS加量对树脂性能影响显著,当DVB用量为0.3%-0.45%、十二烷基苯磺酸钠用量0.15%-0.3%时,制备的P(AMPS+AA)树脂具有较高吸水能力,并且其稳定性比N,N’-亚甲基双丙烯酰胺(NMBA)交联的树脂优良,在高温碱性或酸性条件下显示出良好的耐水解性能。 相似文献
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水稻硝酸还原酶活力的调节 总被引:3,自引:0,他引:3
水稻品种原丰早(籼稻)和京引127(粳稻)的NR在分子量、亚基组成、体外稳定性、免疫学特性、最适pH以及对底物的K_m值等是相同的。在部分纯化的酶液中,原丰早的酶活力衰减速率比京引127慢20%左右。火箭免疫电泳和抗血清滴定结果指出原丰早NR的量比京引127多1.5倍。~3H-氨基酸体内参入NR的试验表明在诱导条件下原丰早NR的从头合成量明显高于京引127。原丰早中NR-mRNA的体外翻译产物也大大高于京引127。可见水稻体内NR活力受酶的合成和酶的钝化系统的调节,酶的合成又受NR-mRNA转录的控制。 相似文献
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Water swelling rubber (WSR) was prepared by reaction blending SBR andsodium polyacrylate (PAANa). The existing states of water in the WSR was studied bymeans of DSC and TG. It was found that water exists in three states: nonfreezing water,bound freezable water and free water. The relationships between water states and structureof PAANa were investigated. The results showed that the amount of non-freezing waterwas related to total water content, and the ratio of non-freezing water versus -COONagroups on PAANa (mol/mol) was about 4. However, total water content slightly affectedthe content of bound freezable water and remarkably affected the amount of free waer. 相似文献
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Wang F Zhang YH Zhao LJ Zhang H Cheng H Shou JJ 《Physical chemistry chemical physics : PCCP》2008,10(28):4154-4158
Micro-Raman spectra of supersaturated aerosols of sodium succinate were obtained. The conformation behavior of the succinate dianion as a function of relative humidity (RH) was investigated by combining micro-Raman spectroscopy with theoretical calculations. A shoulder at 968 cm(-1) of the v(C-CO(2)(-)) band on the rise in more concentrated droplets was believed indicative of conformation transformations. The intensity ratio (I(963)/I(997)) of the v(C-CO(2)(-)) band at 963 cm(-1) to the v(C-C) band at 997 cm(-1), versus the molar water-to-solute ratio (WSR), was used to fathom the equilibrium between gauche and trans conformations. Before saturation (WSR = 25.8) for the droplets, the ratio of I(963)/I(997) retains a value of approximately 2.6 independent of WSR, indicating that the equilibrium was not disturbed in the dilute droplets. In supersaturated droplets (WSR < 25.8), however, the ratio sharply decreases from approximately 2.6 to approximately 1.1 at WSR = 9.6, which was attributed to the formation of contact ion pairs (CIPs). 相似文献
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“Green” composites with different amounts of in situ silica nano-particles were prepared by a sol-gel reaction of tetraethoxysilane (TEOS) in natural rubber (NR). The control of swelling degree of TEOS in NR and concentration of n-butylamine in water was useful to change the amount of generated in situ silica in the uncured NR matrix. In situ silica up to 42 parts per hundred rubber by weight (phr) was successfully filled in the NR matrix. The particle size of in situ silica became larger with the increase of silica content from ca. 10 nm to ca. 40 nm for 10 phr--40 phr loadings in the NR matrix, respectively. Even when the amount of in situ silica content was high, the dispersion of in situ silica particles was more homogeneous than that of commercial silica (VN-3). The reinforcement effect of the in situ silica for NR vulcanizates increased with increasing the in situ silica content. 相似文献
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The states of water in poly (N-vinylpyrrolidone-methylmethacrylate) and poly (N-vinylpyrroli-done-2-hydroxyethyl methacrylate) hydrogels have been studied by means of DSC. The effect ofpolmer structure on equilibrium swelling extent of water has been examined. It was found that thestate of water and the water content in different hydrogels were dependent on the kind of monomer used,the component of copolymer, the sequence distribution of the monomer unit and the degree of cross-linking (including chemical and physical) to a great extent. The equilibrium water content of thehydrogel may be regarded as the sum of the different state of swollen water contents of the hydrogel.Based on these, a semiempirical formula used to estimate the equilibrium water content of the copolymerhydrogels was presented. 相似文献
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Napalai Kongvasana Apisit Kositchaiyong Ekachai Wimolmala Chakrit Sirisinha Narongrit Sombatsompop 《先进技术聚合物》2011,22(6):1014-1023
The loading effect of precipitated silica (PSi) and fly ash‐based silica (FASi) on mechanical properties of natural rubber/chloroprene (NR/CR) under thermal and thermal‐oil ageing was investigated with variation in NR content in the NR/CR blends. The selected results were compared with vulcanized NR/nitrile rubber (NR/NBR) blends. The cure time of CR vulcanizate was found to decrease with increasing NR content, but increased with silica fillers. The Mooney viscosity for CR vulcanizates reduced with increasing NR content. The addition of NR had no effect on tensile modulus and tensile strength for the FASi filled NR/CR, but the opposite trend was observed for the PSi filled NR/CR. The post‐curing effect was more significant in PSi filled NR/CR than in FASi filled NR/CR. The tensile strength of the NR/CR vulcanizates was slightly reduced after thermal ageing especially at high NR content, more extreme reduction being found by thermal‐oil ageing. The elongation at break of NR/CR with both silica fillers ranged from 400 to 900%. The hardness results were similar to the tensile modulus. The addition of PSi in NR/CR considerably increased the tear strength, but less pronounced effect was found for FASi. The resilience properties of NR/CR tended to decrease with increasing silica content. The compression set became poorer when NR content was increased. The PSi showed higher improvement in compression set than the FASi. The effects of silica and ageing on the mechanical properties for NR/CR vulcanizates were similar to those for NR/NBR vulcanizates. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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CARBOXYLATED ZINC-PHTHALOCYANINE, INFLUENCE OF DIMERIZATION ON THE SPECTROSCOPIC PROPERTIES. AN ABSORPTION, EMISSION, AND THERMAL LENSING STUDY 总被引:1,自引:0,他引:1
R. MARTíN NEGRI ANITA ZALTS ENRIQUE A. SAN ROMáN PEDRO F. ARAMENDíA SILVIA E. BRASLAVSKY 《Photochemistry and photobiology》1991,53(3):317-322
Monomer and dimer absorption and emission spectra, and dimerization constants are reported for the diamide of the zinc-tetracarboxyphthalocyanine in pure dimethylformamide (DMF) and in H2O/DMF mixtures at room temperature. The dimerization constant increases steadily with the water content. The monomer absorption Q-band is insensitive to the solvent composition, whereas dimer spectra show great variations with the water content. Stationary emission measurements show that fluorescence originates exclusively from the monomers. The fluorescence spectrum as well as its absolute fluorescence quantum yield, measured by steady-state thermal lensing, are also insensitive to the solvent composition. The thermal lensing method is discussed for the case of two absorbing species in equilibrium. 相似文献