MA/VAc/AA/AMPS四元共聚物的结构特点及其阻垢性能

以马来酸酐(MA)、醋酸乙烯酯(VAc)、丙烯酸(AA)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为单体,异丙醇为链转移剂,通过自由基聚合法成功制备出MA/VAc/AA/AMPS四元共聚物,通过红外光谱仪(FT-IR)对其化学结构进行表征。以阻垢率为考察指标,详细考察了该阻垢剂的质量浓度和溶液的pH对阻硫酸钙性能的影响;并通过SEM和XRD考察了添加阻垢剂后硫酸钙垢晶体的变化情况。实验结果表明,在阻垢剂质量浓度为20 mg/L时,阻硫酸钙的效率可达94.42%。而且通过XRD和SEM分析可知,MA/VAc/AA/AMPS阻垢剂的加入,抑制和破坏了硫酸钙垢晶体的生长和规整性,使硫酸钙晶体发生了不同程度的断裂破损现象,降低了钙垢的结晶度,从而起到良好的阻垢效果。     

MA/MAC/AA/AMPS高效共聚物阻垢剂的制备

在工业生产中,冷却水循环系统的结垢会导致生产效率降低、生产成本增加以及生产不能正常进行,而加入阻垢剂是解决这一难题的有效、经济、简便的方法。因此,以马来酸(MA)、丙烯酸甲酯(MAC)、丙烯酸(AA)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为单体,水为溶剂,过硫酸钾作为引发剂合成了一种新型四元共聚物阻垢剂。研究了不同聚合条件下生成共聚物对碳酸钙阻垢性能的影响,确定了最佳合成条件。结果表明,在单体摩尔n(MA)∶n(AA)∶n(AMPS)∶n(MAC)=8∶5∶3∶4,在引发剂质量为单体总质量的7.5%,反应温度85℃,反应时间3h条件下,共聚物对碳酸钙阻垢效率达94.5%以上。     

AA／AMPS／HPA三元共聚物的合成及性能评定

以过硫酸铵—次亚磷酸钠为氧化还原体系,丙烯酸(AA),2—丙烯酰胺—2—甲基丙磺酸(AMPS)和丙烯酸羟丙酯(HPA)为原料合成了AA/AMPS/HPA三元共聚物,并对其阻垢和缓蚀性能进行了评定,结果表明,AA/AMPS/HPA共聚物不仅本身为性能优越的分散阻垢剂,并能与多种缓蚀剂和阻垢缓蚀剂复合使用,是一种具有很好推广应用前景的高效水稳剂。     

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。     

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。     

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。     

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。     

新型四元共聚物的合成及阻垢性能评价

以衣康酸(IA)、丙烯酸甲酯(MA)、丙烯酰胺(AM)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为原料,通过水溶液自由基聚合的方法合成了四元共聚物阻垢剂,并且利用红外光谱对共聚物的结构进行了分析。通过自制阻垢剂与市售T-225阻垢剂的阻垢性能对比试验,探讨了共聚物的投加量、钙离子质量浓度、水样温度对共聚物阻垢性能的影响,试验结果表明:共聚物投加量为30 mg/L时,此四元共聚物对碳酸钙的阻垢率高达98.7%;在钙离子质量浓度为1 100 mg/L时,四元共聚物阻垢率仍然可以达到75%以上;当水样温度为90℃时,四元共聚物的阻垢性能可以达到90%。此四元共聚物对碳酸钙的阻垢性能均优于市售阻垢剂,特别适用于高温、中等矿化度的工业循环冷却水。     

IA/MA/AMPS三元共聚物阻垢剂的性能评价

针对实验合成的IA/MA/AMPS三元共聚物阻垢剂,分别考察了钙离子质量浓度、水样温度、水样p H值对共聚物阻垢性能的影响,合成的共聚物与市售阻垢剂分散氧化铁的性能进行了对比实验,并对提纯后的IA/MA/AMPS三元共聚物阻垢剂作TG分析。结果表明,合成的三元共聚物阻垢剂具有良好的热稳定性,分散氧化铁性能优于市售阻垢剂,适用于弱碱性、高温、中等矿化度的工业循环冷却水。     

IA/MA/AMPS三元共聚物阻垢剂的性能评价

针对实验合成的IA/MA/AMPS三元共聚物阻垢剂,分别考察了钙离子质量浓度、水样温度、水样p H值对共聚物阻垢性能的影响,合成的共聚物与市售阻垢剂分散氧化铁的性能进行了对比实验,并对提纯后的IA/MA/AMPS三元共聚物阻垢剂作TG分析。结果表明,合成的三元共聚物阻垢剂具有良好的热稳定性,分散氧化铁性能优于市售阻垢剂,适用于弱碱性、高温、中等矿化度的工业循环冷却水。     

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.