IA/N-MAM/SMAS三元共聚物阻垢剂的合成研究

选用衣康酸(IA)、N-羟甲基丙烯酰胺(N-MAM)、甲基丙烯磺酸钠(SMAS)为原料,在过硫酸铵引发下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。分别考察了单体摩尔配比、反应温度、反应时间、引发剂用量对聚合物阻垢剂阻垢性能的影响。确立了IA/N-MAM/SMAS的最佳合成工艺条件为:单体摩尔配比n(IA)∶n(N-MAM)∶n(SMAS)=2.2∶1.0∶1.0,引发剂用量占单体总质量的10%,反应温度为75℃,反应时间为4 h。利用红外光谱仪对共聚物的结构进行了分析表征,结果表明IA/N-MAM/SMAS中含有羧基、酰胺基和磺酸基。     

一种新型无磷共聚物阻垢剂的研究

在水溶液中,以过硫酸铵为引发剂,衣康酸(IA)、丙烯酰胺(AM)、甲基丙烯磺酸钠(SMAS)、丙烯酸甲酯(MA)为反应单体,合成了无磷共聚物(IA/AM/SMAS/MA)。通过正交实验确定了无磷共聚物合成的最佳合成条件。利用红外光谱对共聚物的结构进行了表征,采取静态阻垢的方法评价了阻垢剂阻碳酸钙生成的性能。结果表明:当单体配比n(衣康酸)/n(丙烯酰胺)/n(甲基丙烯磺酸钠)/n(丙烯酸甲酯)=4∶3∶2∶3,引发剂用量为单体的10%(wt),反应温度为90℃,反应时间为4 h。此条件下合成的阻垢剂的阻垢率可以达到88.6%。     

衣康酸三元共聚物阻垢剂的合成及其阻垢性能的研究

以衣康酸(IA)、苯乙烯磺酸钠(SSS)、2,2-二羟甲基丙酸(DMPA)为单体,过硫酸铵为引发剂,采用水溶液自由基聚合法,合成了一种含有羧酸基、磺酸基和羟基的多元衣康酸共聚阻垢剂。研究了反应物单体配比、反应温度、反应时间、引发剂质量分数对共聚物阻垢剂阻垢性能的影响。结果表明,在IA∶SSS∶DMPA(摩尔比)=4∶1∶1.5,引发剂用量占单体质量分数的11%,反应温度为90℃,反应时间为2.5 h条件下制得的共聚物阻垢剂阻垢性能最佳。通过静态阻垢法进行了阻垢剂的阻垢性能的评定,当此三元共聚物阻垢剂加剂量为12 mg/L时,对CaCO_3的阻垢率可达94.9%,用红外光谱和扫描电镜对共聚物阻垢剂的结构和CaCO_3垢样进行了表征。其中扫描电镜表明,加入此衣康酸三元共聚阻垢剂后,CaCO_3呈现明显的疏松结构。     

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。     

衣康酸三元共聚物阻垢剂的合成及其阻垢性能的研究

以衣康酸(IA)、苯乙烯磺酸钠(SSS)、2,2-二羟甲基丙酸(DMPA)为单体,过硫酸铵为引发剂,采用水溶液自由基聚合法,合成了一种含有羧酸基、磺酸基和羟基的多元衣康酸共聚阻垢剂。研究了反应物单体配比、反应温度、反应时间、引发剂质量分数对共聚物阻垢剂阻垢性能的影响。结果表明,在IA∶SSS∶DMPA(摩尔比)=4∶1∶1.5,引发剂用量占单体质量分数的11%,反应温度为90℃,反应时间为2.5 h条件下制得的共聚物阻垢剂阻垢性能最佳。通过静态阻垢法进行了阻垢剂的阻垢性能的评定,当此三元共聚物阻垢剂加剂量为12 mg/L时,对CaCO_3的阻垢率可达94.9%,用红外光谱和扫描电镜对共聚物阻垢剂的结构和CaCO_3垢样进行了表征。其中扫描电镜表明,加入此衣康酸三元共聚阻垢剂后,CaCO_3呈现明显的疏松结构。     

新型三元聚合物阻垢剂的合成及性能评价

在水溶液中,以过硫酸钾为引发剂,马来酸酐(MA)、丙烯酸甲酯(MAC)、甲基丙烯磺酸钠(SMAS)为反应单体,合成无磷聚合物(MA/MAC/SMAS)。探讨了阻垢剂投加量、阻垢实验温度对聚合物阻垢率的影响,在静态试验条件下评价了其对氧化铁的分散性能,用正交实验法确定了最佳合成条件:单体配比n(马来酸酐)∶n(丙烯酸甲酯)∶n(甲基丙烯磺酸钠)=1.5∶0.5∶0.1,引发剂用量为单体的10%(wt),反应温度为80℃,反应时间为3 h。结果表明:引发剂用量是影响聚合物阻垢率的主要因素,该聚合物具有良好的阻垢分散性,阻垢率高达90.1%,     

新型无磷反渗透膜用阻垢剂的制备及性能研究

以衣康酸(IA)、甲基丙烯磺酸钠(SMAS)、天冬氨酸(ASP)为单体,过硫酸铵为引发剂,采用水溶液自由基聚合合成三元共聚物阻垢剂.以单体配比、引发剂用量、聚合温度、聚合时间4因素为基础,设计正交实验优化了共聚物的合成条件.利用红外光谱仪对共聚物的结构进行表征,表明其含有羧基、磺酸基、酰胺基等官能团.采用静态阻垢法考察...     

绿色阻垢剂衣康酸三元共聚物的合成及性能研究

利用亚甲基丁二酸(IA)和甲基丙烯磺酸钠(SMAS)分子结构中的双键,以硫酸亚铁铵为引发剂,通过水相合成法与次亚磷酸钠(SHP)进行共聚反应,合成了衣康酸三元共聚物(IA-SMAS-SHP)。研究了单体配比、反应温度和反应时间对IA-SMAS-SHP阻碳酸钙垢性能的影响,并考察了IA-SMAS-SHP阻磷酸钙垢、阻硫酸钙垢和分散氧化铁的性能。结果表明,衣康酸三元共聚物IA-SMAS-SHP的最佳合成条件为：m(IA)∶m(SMAS)∶m(SHP)=4∶1∶2.5,反应温度90℃,反应时间4 h。合成的IA-SMAS-SHP对碳酸钙垢、磷酸钙垢和硫酸钙垢均有良好的抑制作用,同时具有优异的分散氧化铁性能。     

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。     

IA/AA/AMPS三元共聚物的合成及阻垢性能研究

以水作溶剂,过硫酸铵为引发剂,衣康酸(IA)、丙烯酸(AA)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)为单体,合成了IA/AA /AMPS三元共聚物.探讨了引发剂用量、链转移剂用量、反应温度等对共聚物阻垢性能的影响.结果表明,引发剂用量为单体总质量的4.5%,链转移剂用量为单体总质量的9.5%,反应温度为95℃时,共聚...     

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.