IA/MA/AMPS三元共聚物阻垢剂的合成研究

以衣康酸(IA)、丙烯酸甲酯(MA)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为单体,过硫酸铵为引发剂,采用水溶液自由基聚合方法合成了一种三元共聚物阻垢剂。经过单因素实验对影响共聚物阻垢性能的因素进行优化后,确立了最佳反应条件。通过静态法对三元共聚物的阻垢性能进行评价,在共聚物加剂量为50 mg/L时,对CaCO3的阻垢率最佳可达91.4%,并用红外光谱和扫描电子显微镜对共聚物的结构和Ca CO3垢样进行了分析。     

一种三元共聚物无磷阻垢剂的研制

以马来酸酐、丙烯酸、2-丙烯酰胺基-2-甲基丙磺酸为原料,水为溶剂,过硫酸铵为引发剂合成了三元共聚物无磷阻垢剂。通过考察不同的因素对共聚物的阻垢性能的影响,确定了该共聚物的最佳合成工艺条件。通过与其它阻垢剂的阻垢性能对比实验,在最佳合成条件的三元共聚物无磷阻垢剂具有优异的阻碳酸钙垢性能。     

马来酸酐/丙烯酸/丙烯酸甲酯共聚阻垢剂的合成及应用性能研究

以马来酸酐、丙烯酸、丙烯酸甲酯为原料合成了新型三元共聚物阻垢分散剂,探讨了单体配比、引发剂用量、聚合温度、聚合时间等对共聚物阻垢性能的影响,得出了最佳合成条件:引发剂用量4%;n(马来酸酐):n(丙烯酸):n(丙烯酸甲酯)=2∶2∶1;反应温度70℃;反应时间3 h;得到的产品阻垢率为88.37%。并研究了水质条件及共聚物用量与阻垢性能之间的关系。     

三元共聚物P(IA/MA/AMPS)的合成及阻垢性能评价

以衣康酸(IA)、马来酸(MA)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为单体,以过硫酸铵为引发剂,以水为溶剂,通过自由基聚合合成了一种新型的三元共聚物,探讨了单体配比、聚合温度、引发剂用量、聚合时间等合成条件对阻垢性能的影响,确定了最佳的合成条件为:单体配比n(IA)∶n(MA)∶n(AMPS)=1∶1∶1,聚合温度80℃,引发剂占单体质量分数的5%,聚合时间2h;用红外分光光度仪分析证明得到了预期的产物结构,并测定了产物的特性黏度和固含量。通过静态法对三元共聚物的阻垢性能进行评价,在加剂量为50mg/L时阻碳酸钙率最佳可达93.6%,是一种性能优异的阻垢剂。     

AA-SAS-IA三元聚合物的合成及阻垢性能评价

以衣康酸(IA)、烯丙基磺酸钠(SAS)和丙烯酸(AA)为原料,过硫酸铵为引发剂,采用水溶液自由基聚合法合成了一种三元共聚物阻垢剂,通过红外光谱表征了共聚物的结构。经过4因素3水平正交实验考察不同条件对阻垢率的影响,确立了最佳反应条件。通过碳酸钙沉积法对三元共聚物的阻垢性能进行了评价,并与有机膦酸盐类阻垢剂进行了对比。在合成的共聚物加量为10 mg/L时,对CaCO_3的阻垢率可达90%以上,可将垢样晶型转为疏松的片层结构。     

AA-SAS-IA三元聚合物的合成及阻垢性能评价

以衣康酸(IA)、烯丙基磺酸钠(SAS)和丙烯酸(AA)为原料,过硫酸铵为引发剂,采用水溶液自由基聚合法合成了一种三元共聚物阻垢剂,通过红外光谱表征了共聚物的结构。经过4因素3水平正交实验考察不同条件对阻垢率的影响,确立了最佳反应条件。通过碳酸钙沉积法对三元共聚物的阻垢性能进行了评价,并与有机膦酸盐类阻垢剂进行了对比。在合成的共聚物加量为10 mg/L时,对CaCO_3的阻垢率可达90%以上,可将垢样晶型转为疏松的片层结构。     

马来酐-丙烯酰胺-丙烯酸羟乙酯共聚阻垢剂的研究

以马来酐、丙烯酰胺、丙烯酸羟乙酯为原料合成了新型三元共聚物阻垢分散剂,探讨了对共聚物阻垢性能的影响因素,得出了最佳合成条件:单体配比n(MA):n(AM):n(HEA)=1.5:0.6:0.4、引发剂与单体质量比为8%、聚合温度80℃、聚合时间4 h.阻垢性能试验表明该共聚物相对分子质量为2 400及共聚物质量浓度为15 mg/L时阻垢效果最好.该共聚物具有良好的阻垢性能,是一种高效的绿色阻垢剂.     

AA/HPA/SVS三元共聚物阻垢剂的合成及其性能研究

以丙烯酸(AA),丙烯酸羟丙酯(HPA)和乙烯基磺酸钠(SVS)为单体,过硫酸铵为引发剂,异丙醇为链转移剂,在水相中进行自由基聚合反应,合成了AA/HPA/SVS水溶性三元共聚物阻垢剂.系统考察了聚合工艺条件对该共聚物阻垢效果的影响,并对其阻垢分散性能进行了初步评价.结果表明,n(AA):n(HPA):n(SVS)为3:1:1,引发剂用量为14%,链转移剂用量为10%,反应温度为90℃,反应时间为2.5 h时,合成的共聚物阻垢性能最佳,在用量为16 mg·L-1时对碳酸钙和磷酸钙的阻垢率均能达到90%以上,并且具有较好的钙容忍度和分散氧化铁性能.     

ESA/AMPS共聚物阻垢性能与机理研究

以马来酸酐(MA)为原料合成环氧琥珀酸(ESA),ESA在过硫酸铵为引发剂下与2-丙烯酰胺基-2-甲基丙磺酸(AMPS)共聚,得ESA/AMPS共聚物。利用傅里叶红外光谱仪(FT-IR)对产物进行了表征。采用静态阻垢法测定ESA/AMPS共聚物对CaCO_3、Ca_3(PO_4)_2和Fe_2O_3的阻垢分散性能。采用扫描电子显微镜(SEM)和X-射线衍射仪(XRD)考察了ESA/AMPS共聚物对CaCO_3垢表面形貌和晶型的影响,探讨了ESA/AMPS聚合物的阻垢机理。结果表明,ESA/AMPS聚合物对CaCO_3、Ca_3(PO_4)_2和Fe_2O_3具有良好的阻垢分散性能,且能够改变CaCO_3晶体的形貌和结构。     

IA/MA/MAA/AMPS共聚物阻垢剂的合成及阻垢性能

以衣康酸、丙烯酸甲酯、甲基丙烯酸、2-丙烯酰胺基-2-甲基丙磺酸为单体,通过水溶液聚合的方法合成了新型四元共聚物阻垢剂,并通过红外光谱确定了共聚物结构。探讨单体配比、反应时间、引发剂用量对共聚物阻垢性能的影响。将合成共聚物与市售阻垢剂进行分散氧化铁性能对比试验,结果表明:该四元共聚物的分散氧化铁性能优于市售阻垢剂,在共聚物质量浓度为40 mg/L时,对Ca CO3的阻垢率为92.7%,对Ca3(PO4)2的阻垢率为88.5%。     

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.     

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.     

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.