MA/AA/SSS三元共聚物的制备及其阻垢性能研究

以马来酸酐(MA)、丙烯酸(AA)、对苯乙烯磺酸钠(SSS)为单体,水作溶剂,过硫酸铵为引发剂,异丙醇为链转移剂,通过自由基聚合法制备了具有阻垢性能MA/AA/SSS三元共聚物。采用红外光谱法(FTIR)和热重分析(TG)等物理手段对聚合物化学结构及热稳定性进行表征。以共聚物的阻垢率为考察指标,系统研究了单体摩尔比、反应温度、反应时间、引发剂用量、链转移剂用量等因素对其阻垢性能的影响。研究结果表明,当MA、AA、SSS的摩尔比为4∶2∶1,反应温度为80℃,反应时间为4 h,引发剂用量为单体总质量的10%,链转移剂用量为单体总质量9%时,共聚物对Ca CO_3阻垢率可达85.6%。     

AA-AMPS共聚物陶瓷分散剂的制备及分散性能

以丙烯酸和2-丙烯酰胺基-2-甲基-丙烷磺酸(AMPS)为单体,过硫酸铵(NH4)2S2O8作为引发剂,次亚磷酸氢钠作为链转移剂,通过自由基聚合反应合成共聚物PAA-AMPS。探讨了不同反应条件对共聚物分散性能的影响,共聚物分散剂PAA-AMPS的最佳合成条件为:丙烯酸(AA)与2-丙烯酰胺基-2-甲基-丙烷磺酸(AMPS)的摩尔比为8∶1;引发剂(NH4)2S2O8用量为单体总质量的1%;链转移剂次亚磷酸氢钠的用量为单体总质量的10%;单体质量分数为24%;反应温度85℃。通过FTIR、GPC及1HNMR等手段对共聚物的结构及相对分子质量及其分布进行了表征,并对添加不同量分散剂的料浆的黏度进行研究。结果表明,聚合物质量分数为0.3%,料浆的黏度最低,与进口产品PC-67(PAA-Na)相比,共聚物PAA-AMPS的分散效果更好。     

含磷AA/AMPS共聚物的合成及阻垢性能研究

以水为溶剂，丙烯酸（AA），2-丙烯酰胺基-2-甲基丙磺酸（AMPS）和次磷酸钠为原料，合成了含磷AA/AMPS共聚物阻垢分散剂。探讨了单体配比，引发剂用量，反应温度等对共聚物阻垢性能的影响。得出了最佳合成条件：m(AA);m(AMPS)=75:25，引发剂与单体（AA和AMPS）的质量比为10%，反应时间4h，反应温度90℃，并采用静态实验法评价了共聚物的阻垢性能，结果表明，含磷AA/AMPS共聚物阻垢性能优良。     

衣康酸/苯乙烯磺酸/丙烯酸共聚物阻垢剂的合成研究

以衣康酸(IA)、苯乙烯磺酸(SSA)和丙烯酸(AA)为单体,过硫酸铵为引发剂,异丙醇为链转移剂,在水相中合成了IA/SSA/AA共聚物阻垢剂.通过正交试验确立了最佳合成工艺条件:单体质量比m(IA):m(SSA):m(AA)=2:1:4,引发剂与总单体的质量比为4.5%,链转移剂与总单体质量比为9.5%,在95℃下反应2 h.当IA/SSA/AA共聚物的极限黏数为5.5～6.0 mL/g,实验水中Ca2 的质量浓度为1.6g/L,阻垢剂投加质量浓度为10 mg/L时,共聚物阻CaCO3垢的阻垢率高达91.9%,特别适用于高矿化度的工业循环冷却水和油田回注水.     

正交设计法合成共聚物型水泥降失水剂的研究

本文利用2-丙烯酰胺基-2-甲基丙磺酸(AMPS)／丙烯酰胺(AM)／丙烯酸(AA)三种单体,根据自由基聚合原理,合成一种三元共聚物型油井水泥降失水剂。利用正交设计法设计了实验方案,分别考察了单体配比、反应温度、引发剂用量和链转移剂用量等因素对其降失水性能的影响,并对产物进行了’红外光谱、差热分析和N、S元素的测定。分析表明单体配比和反应温度是影响聚合物降失水性能的主要因素,并得到了最佳的合成方案：AMPS：AM：AA=50：42：8,反应温度70℃,引发剂用量2％,链转移剂用量6％。     

SSS—AMPS—AA共聚物阻垢剂的合成

以苯乙烯磺酸钠（SSS）,2-丙烯酰胺基-2-甲基丙磺酸（AMPS）和丙烯酸（AA）为单体,过硫酸铵为引发剂,次亚磷酸钠为链转移剂,在水相中合成了SSS／AMPS／AA共聚物,通过正交实验确立了最佳合成工艺条件。利用静态试验法评价了合成产物阻CaCO3垢性能,探讨Tel发剂的用量、链转移剂用量、反应温度对共聚物阻垢性能的影响。     

AA-AMPS共聚物陶瓷分散剂的制备及分散性能研究

以丙烯酸和2-丙烯酰胺基-2-甲基-丙烷磺酸(AMPS)为单体,过硫酸铵(NH4)2S2O8作为引发剂,次亚磷酸氢钠作为链转移剂,通过自由基聚合反应合成共聚物PAA-AMPS。探讨了不同反应条件对共聚物分散性能的影响,共聚物分散剂PAA-AMPS的最佳合成条件为：丙烯酸（AA）与2-丙烯酰胺基-2-甲基-丙烷磺酸(AMPS)的摩尔比为8:1;引发剂(NH4)2S2O8用量为单体质量的1 %;链转移剂次亚磷酸氢钠的用量为单体质量的10%;单体质量分数为24%;反应温度85 ℃。通过FT-IR、GPC 及TGA等手段对共聚物的结构、热稳定性以及相对分子质量及其分布进行了表征,并对添加不同量的分散剂的料浆粘度进行研究。结果表明,聚合物质量分数为0.25%,料浆的粘度最低,共聚物的分散效果最好。     

聚醚型阻垢分散剂合成工艺条件的研究

以丙烯酸(AA)和聚乙二醇单甲醚甲基丙烯酸酯(MPEGMA)为共聚单体,以过硫酸铵-次亚磷酸钠为引发体系,以磷酸二氢钾为链转移剂,采用水溶液共聚的方法制备出具有长侧链醚基的聚醚型阻垢剂P(AA/MPEGMA);研究了单体配比、引发剂用量、链转移剂用量、反应温度及反应时间对共聚物阻碳酸钙垢率的影响。研究结果表明,当丙烯酸(AA)与聚乙二醇单甲醚甲基丙烯酸酯(MPEGMA)的质量比为3∶1,引发剂用量为单体质量的4.5%,链转移剂用量为单体质量的11%,反应温度为82℃,聚合反应时间为3.5 h时,共聚物阻碳酸钙垢率最大。     

一种水溶性AM/AA/AI共聚物的合成及性能研究

由丙烯酰胺(AM)、丙烯酸(AA)、烯丙基咪唑(AI)在过硫酸铵-亚硫酸氢钠氧化还原引发体系下合成了一种新型的AM/AA/AI水溶性三元共聚物。确立了最佳反应条件:AM∶AA=2∶1(wt%),单体AI的用量为0.1wt%(占单体总质量),引发剂用量0.45wt%,反应温度40℃;并通过红外光谱分析确认了AM/AA/AI三元共聚物结构。当NaCl,CaCl2浓度分别在12000 mg/L,1400 mg/L时,AM/AA/AI三元共聚物的粘度保留率分别约为41%,30%。     

IA/AA/AMPS水煤浆分散剂的制备及性能

以丙烯酸(AA)、衣康酸(IA)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)为反应单体,过硫酸钾和亚硫酸氢钠为氧化-还原体系引发剂,通过自由基聚合制备了IA/AA/AMPS三元共聚物水煤浆分散剂,并通过红外光谱(IR)、黏度仪进行了测试。结果表明,共聚物中引入了磺酸基和羧酸基;同时,对不同水煤浆质量分数和不同分散剂添加量的水煤浆进行了研究,水煤浆的最佳成浆质量分数为68%,当添加质量分数为0.6%的分散剂时,分散效果最佳。     

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.     

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.     

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.     

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.     

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.