丙烯酸酯共聚物/磷酸酯复配体系阻垢作用研究

以丙烯酸(AA)、丙烯酸羟丙酯(HPA)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)为单体,丙二醇甲醚为溶剂,采用自由基溶液聚合法制备AA/HPA/AMPS聚合物阻垢剂,并与羟基乙叉二磷酸(HEDP)、氨基三亚甲基叉磷酸(ATMPA),柠檬酸以质量比为3∶3∶2∶1配制复配型阻垢剂。通过电导法测阻垢率,利用SEM观察硫酸钡晶体表面的变化。结果证明,在BaCl_2浓度0.1 mol/L时,复配型阻垢剂阻垢率可达97.54%,比丙烯酸酯聚合物平均高出28%。加入复配型阻垢剂BaSO_4晶体的立方体结构被破坏,垢样呈现松散无序、晶格畸变和扭曲的现象。     

丙烯酸酯共聚物/磷酸酯复配体系阻垢作用研究

以丙烯酸(AA)、丙烯酸羟丙酯(HPA)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)为单体,丙二醇甲醚为溶剂,采用自由基溶液聚合法制备AA/HPA/AMPS聚合物阻垢剂,并与羟基乙叉二磷酸(HEDP)、氨基三亚甲基叉磷酸(ATMPA),柠檬酸以质量比为3∶3∶2∶1配制复配型阻垢剂。通过电导法测阻垢率,利用SEM观察硫酸钡晶体表面的变化。结果证明,在BaCl_2浓度0.1 mol/L时,复配型阻垢剂阻垢率可达97.54%,比丙烯酸酯聚合物平均高出28%。加入复配型阻垢剂BaSO_4晶体的立方体结构被破坏,垢样呈现松散无序、晶格畸变和扭曲的现象。     

聚天冬氨酸/邻氨基酚磺酸的合成及其阻垢性能

以邻氨基酚磺酸（3A4HBSA）与聚琥珀酰亚胺(PSI)为原料，合成了聚天冬氨酸接枝共聚物阻垢剂PASP/3A4HBSA。用FTIR与1HNMR对阻垢剂的结构进行了表征，用静态阻垢法考察了PASP/3A4HBSA和聚天冬氨酸(PASP)对碳酸钙的阻垢性能。得到的最佳实验条件为：当阻垢剂质量浓度为100mg/L、温度为70℃、时间24h、pH =7时，PASP/3A4HBSA对CaCO3的阻垢率达到92.7%，而PASP对CaCO3的阻垢率只有77.1%。用SEM与XRD对处理前后的垢样表面结构和物相结构进行了表征，并分析阻垢剂的阻垢机理，用红外光谱测定进一步分析阻垢剂的阻垢机理，结果表明：阻垢剂对CaCO3的作用主要包括晶格畸变作用和络合作用。     

复配阻垢剂对硫酸钡阻垢效果实验

采用钡离子络合滴定法,展开了不同类型的硫酸钡垢阻垢剂复配实验研究。阻垢剂DTPMPA和TM-5A按2∶1复配时,阻垢率为88. 4%;阻垢剂DTPMPA、TPA与TM-5A按3∶1∶1复配时,阻垢率为90. 31%。在上述两种复配比例下,考察了阻垢剂浓度、温度、矿化度、p H值4种因素对硫酸钡垢阻垢效果的影响。结果表明,两种复配阻垢剂的阻垢率曲线变化整体趋势相似:随复配阻垢剂浓度的增加阻垢率先增大再缓慢减小;随温度的增加阻垢率先增大再减小,75℃时阻垢效果最佳;随矿化度增加阻垢率先增大再小幅度减小;随p H值增加阻垢率先增大再减小,p H=7. 5时阻垢效果最佳。DTPMP、TPA与TM-5A按3∶1∶1复配时,阻垢率曲线起伏变化较大,复配阻垢剂稳定性较差; DTPMPA与TM-5A按2∶1复配时,各因素作用下阻垢效果均较为稳定,阻垢率达到88. 4%。     

PASP和ATMP复合阻垢剂阻垢性能研究

采用静态阻垢法对聚天冬氨酸(PASP)与氨基三亚甲基膦酸(ATMP)复配物阻垢性能进行研究。考察阻垢剂添加量、温度、Ca2+浓度、HCO3-浓度、恒温时间对阻垢率的影响。结果表明,复配物的阻垢性能较单一的聚天冬氨酸有一定的提高。复配物的最佳质量配比为1∶1,PASP和ATMP总加入量为4 mg/L时效果最佳,阻垢率达86%。复配物阻垢性能受温度、时间、HCO3-浓度的影响较小,受Ca2+浓度的影响较大。对复合阻垢剂进行了经济性评价,复合阻垢剂可降低单独使用时的成本。     

阻垢剂阻垢性能比较

文章通过碳酸钙沉积法对PBTCA、ATMT、HEDP、PAPE、HPMA、AA/AMPS、HPMA、PESA、PSAP的阻垢性能进行测定,分别用螯合阻垢性能及非粘附阻垢性能表示各阻垢剂的阻垢能力。并提出非粘附阻垢性能比螯合阻垢性能更能反映阻垢剂的阻垢能力。     

复合阻垢剂PASP-ATMP的协同效应及影响因素研究

采用静态阻垢法,研究了聚天冬氨酸(PASP)与氨基三甲叉膦酸(ATMP)复配体系的协同效应,考察阻垢剂添加量、温度、pH值、Ca2+浓度、HCO3-浓度对阻垢性能的影响。结果表明,复配体系的阻垢性能较单一阻垢剂好,PASP/ATMP质量比在2∶3时,阻垢性能最优,当复合阻垢剂PASP-ATMP投加量为5 mg/L时,阻垢率高达93.04%。复配体系阻垢性能随温度、pH值、Ca2+浓度、HCO3-的增加虽然有所下降,但仍表现出一定钙容忍度及适合高pH值、高HCO3-环境使用等特性。     

低磷复配缓蚀阻垢剂在循环冷却水中的研究与应用

以咪唑啉季铵盐、膦羧酸共聚物、丙烯酸-丙烯酸酯-磺酸盐共聚物、锌盐为主要成分复配低磷缓蚀阻垢剂,采用旋转挂片腐蚀试验、静态阻垢试验、动态模拟试验评价其缓蚀性能和阻垢性能。试验结果表明,上述4种成分按2.0∶1.0∶1.5∶1.0的质量比复配成低磷缓蚀阻垢剂,该药剂投加量为30 mg/L时,其缓蚀率和阻垢率分别为95.85%和91.62%。将该低磷缓蚀阻垢剂现场应用于鲅鱼圈钢铁燃气蒸汽联合循环发电机组(CCPP)的净环水处理系统,也取得良好的使用效果。     

聚天冬氨酸/O-羧甲基壳聚糖的合成及其对硫酸钡阻垢性能

以水溶性O-羧甲基壳聚糖(O-CMC)与聚琥珀酰亚胺(PSI)为原料,合成了聚天冬氨酸接枝共聚物阻垢剂PASP/O-CMC。用FTIR与1HNMR对阻垢剂的结构进行了表征,用静态阻垢法考察了PASP/O-CMC和聚天冬氨酸(PASP)的阻垢性能。结果表明:当阻垢剂质量浓度为100 mg/L、温度为80℃、时间为16 h、pH=10时,PASP/O-CMC对BaSO_4的阻垢率达到93.6%,而PASP对BaSO_4的阻垢率只有78.4%。通过SEM、XRD和电导率法分析了阻垢剂的阻垢机理,结果表明:阻垢剂对BaSO_4的作用主要包括晶格畸变作用、吸附分散作用和络合作用。     

低膦水解聚马来酸酐阻垢剂合成研究

以水为溶剂,均相催化引发H2O2产生.OH,合成了低膦水解聚马来酸酐(PHPMA)阻垢剂。研究了原料质量配比、反应温度、催化剂加量、反应时间及阻垢剂加量对阻垢效果的影响。得出最佳合成工艺:m(马来酸酐)∶m(次亚磷酸钠)∶m(引发剂)∶m(水)=12∶4.5∶13∶12,催化剂用量为0.05%,反应时间3 h,温度95℃。PHPMA投加质量浓度为4 mg/L时,其静态阻垢率达99.61%。结果表明,采用均相催化能够合成低膦水解聚马来酸酐高效阻垢剂。     

Wet Milling of Fe/Al/Al2O3 and Fe2O3/Al/Al2O3 Powder Mixtures

Wet milling of Al₂O₃-aluminide alloy (3A) precursor powders in acetone has been investigated by milling Fe/Al/Al₂O₃ and Fe₂O₃/Al/Al₂O₃ powder mixtures. The influence of the milling process on the physical and chemical properties of the milled powders has been studied. Particle refinement and homogenization were found not to play a dominant role, whereas plastic deformation of the metal particles leads to the formation of dislocations and a highly disarranged polycrystalline structure. Although no chemical reactions among the powder components in Fe₂O₃/Al/Al₂O₃ powder mixtures were observed, the formation of a nanocrystalline, ordered intermetallic FeAl phase in Fe/Al/Al₂O₃ powder mixtures caused by mechanical alloying was detected. Chemical reactions of Fe and Al particle surfaces with the atmosphere and the milling media lead to the formation of highly porous hydroxides on the particle surfaces. Hence the specific surface area of the powders increases, while the powder density decreases during milling. The fraction of Fe oxidized during milling was determined to be 0.13. The fraction of Al oxidized during milling strongly depends on the metal content of the powder mixture. It ranges between 0.4 and 0.8.     

Preparation and properties of poly(Nε,Nε-dicarboxymethyl-l-lysine)

A new ampholytic homopolypeptide, $\text{poly}\text{(N}{}^{\mathrm{\epsilon }}\text{,N}{}^{\mathrm{\epsilon }}\text{-}\text{dicarboxy-methyl-}\text{l}\text{-lysine}\text{)}$, which has one tertiary amino and two carboxyl groups in the side chain has been derived from a hydrochloride salt of poly(L-lysine). The polymer in aqueous solution seems to be in the coil form with locally extended structure (LES) at neutral pH. In both the acidic and alkaline regions, the molar ellipticity of the polymer changes as a result of change in net charge on the side chain. The conformational changes may be from the coil with LES to other coiled forms. 5–7 M NaClO₄ and 80% aqueous methanol induce the α-helix in the polymer at neutral pH. Divalent cations, Cu²⁺ and Ca²⁺, do not induce any remarkably ordered structures such as α-helix or β-structure in the polymer in aqueous solution at any pH. Ultraviolet absorption studies show an absorption peak of the polymer-Cu²⁺ complex near 240 nm. Dependence of the peak intensity on pH at various q values ($\text{q =}\text{[}\text{Cu}{}^{\mathrm{2+}}\text{]}\text{[}\text{residue}\text{]}$) indicates the two steps of the complex formation. At q less than 0.64, the formation is described only with the first step. An average coordination number for Cu²⁺ at the first step was calculated to be about 2 by the method of Mandel and Leyte. The association constant of Cu²⁺ with the residue at the step was determined from the absorption data to be far smaller than that for the Cu²⁺-EDTA complex. The second step of the formation occurs in the case of large q but the absorption data for the second step cannot be obtained exactly due to precipitation.     

Sintering of Si3N4-Y2O3-Al2O3

Sintering kinetics of the system Si₃N4-Y2O₃-Al₂O3 were determined from measurements of the linear shrinkage of pressed disks sintered isothermally at 1500° to 1700°C. Amorphous and crystalline Si₃N₄ were studied with additions of 4 to 17 wt% Y₂O₃ and 4 wt% A1₂O₃. Sintering occurs by a liquid-phase mechanism in which the kinetics exhibit the three stages predicted by Kingery's model. However, the rates during the second stage of the process are higher for all compositions than predicted by the model. X-ray data show the presence of several transient phases which, with sufficient heating, disappear leaving mixtures of β ' -Si₃N₄ and glass or β '-Si₃N₄, α '-Si₃N₄, and glass. The compositions and amounts of the residual glassy phases are estimated.     

Participation of lewis base on vinyl chloride polymerization with Al(C2H5)3CCl4 catalyst system

The polymerization of vinyl chloride has been investigated using an $\text{Al}\text{(}\text{C}{}_2\text{H}{}_5\text{)}{}_3\text{CCl}{}_4$ catalyst system in the presence of various Lewis bases. Effective Lewis bases are γ-butyrolactone, diglyme and diethylenetriamine which are multidentate. The rate of polymerization is dependent not only on the basicity of the Lewis base used but also on a coordination number of one. The latter is the predominant factor. For the effect of polymeric amines, a tentative hypothesis is discussed.     

Ag2O-Doped Bi2Sr2Ca1Cu2Ox Superconductors Prepared via Melt-Quenching

Ag₂O-doped superconducting Bi₂Sr₂Ca₁Cu₂O _x ceramics were prepared by a melt-quenching–reheating method. It is found that the Ag₂O-doped, as-cast specimens exhibit superconductivity ( T _c= around 80 K) by heat treatment at temperatures around 800°C even in an evacuated and sealed silica glass tube, while the undoped specimens do not and vaporize by the corresponding heat treatment. Conversion of the Ag₂O-doped, as-cast specimens into superconducting ceramics when heated in an evacuated vessel is explained in terms of the oxygen donor of Ag₂O in the specimen. This finding enables us to fabricate a desired shape of superconducting Bi₂Sr₂Ca₁Cu₂O _x ceramics sealed in metals or glasses. The addition of Ag₂O to Bi₂Sr₂Ca₁Cu₂O _x melt, however, had deleterious influences on the superconducting properties ( T _c and J _c) of the resultant ceramics when obtained by heat treatment in air.     

Synthesis and Characterization of Ti0.33Ta0.33Nb0.33C and Ti0.33Ta0.33Nb0.33CxN1-x Whiskers

Ta_0.33Ti_0.33Nb_0.33C and Ta_0.33Ti_0.33Nb_0.33C _x N_{1− x} whiskers were synthesized via a carbothermal vapor-liquid-solid growth mechanism in the temperature range 900°-1450°C in Ar or N₂. The optimum temperature was 1250°C. Whiskers were obtained in a yield of 70-90 vol%. The whiskers were 0.5–1 µm in diameter and 10–30 µm in length. The starting materials that produced the highest whisker yield were: TiO₂, Ta₂O₅, Nb₂O₅, C, Ni, and NaCl. C was added to reduce the oxides, and Ni to catalyze whisker growth. NaCl was used as a source of Cl for vapor-phase transportation of Ta and Nb oxochlorides and Ti chlorides to the catalyst. The catalyst metal was recycled several times during the synthesis and was transported as NiCl₂( g ) according to thermodynamic calculations. The rate of formation and the chemical composition of the whiskers depended on the synthesis temperature, the choice of catalyst, and the atmosphere. At low temperatures, the whiskers were enriched in Nb and Ta, whereas the Ti content increased with increased synthesis temperature.