含三嗪环非离子表面活性剂制备及其性能研究

以三聚氯氰、脂肪胺、聚乙二醇单甲醚(mPEG)为原料合成了6种均三嗪非离子表面活性剂。采用FTIR1、HNMR对中间体和目标产物进行了结构表征。考察了25℃时6种产品的表面张力、临界胶束浓度及其乳化力。结果表明,该类非离子表面活性剂具有较好的表面活性,其中DMAT-600的临界胶束浓度(cmc)和cmc下的表面张力(γcmc)分别可达0.162g/L和31.94mN/m;产品具有较强的乳化力,乳化力介于8.2~20.5min。     

新型可聚合硼酸酯表面活性剂的合成及其性能

以硼酸三乙酯、N-羟甲基丙烯酰胺、N,N-二羟乙基十二烷基胺等为主要原料,合成了新型可聚合非离子硼酸酯表面活性剂(BE),由IR和1HNMR进行表征和确认,并考察了产物的抗水解性、表面活性、均聚合及与丙烯酰胺的共聚合性能。结果表明:合成产物BE抗水解能力强,表面活性较高,pH=7时,cmc为0.066 mmol/L,γcmc为29.2 mN/m;BE有较强的均聚合和共聚合能力,产物特性黏度分别可达24.0 mL/g和80.0 mL/g以上;BE聚合产物也具有较好的表面活性,γcmc可达31.0 mN/m~32.4 mN/m,达到了常规低相对分子质量表面活性剂的表面张力水平。     

十二烯基琥珀酸淀粉酯的表面性质研究

以直链十二烷基苯磺酸钠（LAS）为参照样,研究了十二烯基琥珀酸淀粉酯（DDSS）表面活性剂的表面张力、硬水稳定性、发泡力及泡沫稳定性等理化特性。结果表明：DDSS具有较好的表面活性,其临界表面张力（γcm）c和临界胶束浓度（cmc）分别为27.786 mN/m和0.49 g/L。DDSS在硬水中具有更好的稳定性,但发泡力和泡沫稳定性较低。DDSS在日化领域具有广泛的应用前景。     

一种高分子两性含氟表面活性剂的合成及其溶液性质

以甲基丙烯酸三氟乙酯(TFEMA)、丙烯酸(AA)、氯丙烯(AC)、三甲胺(TMA)为原料,合成了一种高分子两性含氟表面活性剂,通过红外光谱对该表面活性剂进行了结构表征.测试了该两性含氟表面活性剂的溶液性质,结果表明,该表面活性剂水溶液的等电点为pH 4.5～7.5、cmc为4.0×10-2g/L、γcmc为59.1 mN/m、泡沫稳定性为0.89.两性含氟表面活性剂含强碱性N原子,pH对表面活性剂的临界胶束浓度有一定影响,但对泡沫性能影响不大.     

甲基偶联双（烷基酚磺酸钠）型Gemini表面活性剂的合成及性能

本文采用甲醛为偶联剂对长链烷基酚进行缩合,合成了可以制备Gemini表面活性剂的疏水骨架——甲基偶联双（烷基酚）（MBA）。将MBA磺化及中和制得了Gemini表面活性剂甲基偶联双（烷基酚磺酸钠）（MBSA）。采用IR、ESI-MS验证了MBSA的结构,并测定了两种Gemini表面活性剂的表面张力、临界胶束浓度、增溶能力、润湿力、泡沫性能、乳化力、钙皂分散力及耐电解质能力。结果表明,甲基偶联双（壬基酚磺酸钠）（MBSN）的cmc为5.9×10-4mol/L,γcmc为30.0mN/m;甲基偶联双（十二烷基酚磺酸钠）（MBSD）的cmc为4.6×10-4mol/L,γcmc为32.0mN/m。其cmc均比普通表面活性剂低一个数量级;疏水基长的MBSD比疏水基短的MBSN表面活性更强,但耐电解质能力反而降低。     

Gemini型阳离子烷基糖苷表面活性剂性能研究

用Wilhelmy法对Gemini阳离子烷基糖苷表面活性剂(G-CAPG)的表面张力进行了测定,25℃,其cmc为0.12 mmol/L,γcmc为30.2 mN/m,Krafft点为-4.41℃,表面活性较好。应用性能研究表明,其保持了APG优异的泡沫性能和去污能力,且几乎不受水硬度的影响;渗透和乳化性能优于常见的阴、阳离子和两性表面活性剂;与LAS复配时,当n(G-CAPG)/n(LAS)<0.6或n(G-CAPG)/n(LAS)>2.0时,溶液的透光率均大于90%,当n(G-CAPG)/n(LAS)=0.5/1时,其去污值达到66.01%,其水溶液的表面张力达到27.3 mN/m;对杆状菌和大肠杆菌的杀菌作用良好;10 d内生物降解度达到94.8%以上,生物降解性能较好。     

N-酰基苯丙氨酸钠表面活性剂的合成和性能研究

以十二酰氯、十四酰氯、十六酰氯和苯丙氨酸为原料,肖顿鲍曼法合成了3种不同碳链长度的N-酰基苯丙氨酸钠表面活性剂:N-十二酰基苯丙氨酸钠(C_(12)PheNa)、N-十四酰基苯丙氨酸钠(C_(14)PheNa)和N-十六酰基苯丙氨酸钠(C_(16)PheNa)。通过红外光谱(FTIR)、核磁共振氢谱(¹H NMR)对产物的结构进行了表征。考察了三种表面活性剂的表面活性、泡沫、乳化、润湿性能。结果表明,随着碳链长度的增加(C_(12)～C_(16)),N-酰基苯丙氨酸钠表面活性剂的临界胶束浓度(cmc)由0.15 mmol/L减少至0.02 mmol/L,对应的表面张力(γ_(cmc))由34.56 mN/m降低至31.52 mN/m;随着烷基碳链的增长,乳化性能越好,润湿性能越差;起泡性能随着烷基链的增加呈现先增加后减少,泡沫稳定性随着烷基链的增加而增加。     

无机盐阳离子对十二烷基硫酸钠表面活性剂降低水的表面张力效果的机理研究

采用真球气泡法测定了不同价态(Na⁺、Cu²⁺、Fe³⁺)和浓度的无机盐体系下十二烷基硫酸钠(SDS)表面活性剂溶液的表面张力、表面扩展黏度和临界胶束浓度(cmc),加入无机盐之后,SDS的cmc值由8 mmol/L降至3 mmol/L,达到最低表面张力的SDS浓度值(C_t)和最大表面扩展黏度时的SDS浓度值(C_v)均小于未添加时对应的SDS浓度,且C_t=C_v=cmc=3 mmol/L。在cmc值时,溶液表面张力为37.29 mN/m,加入NaCl后溶液表面张力为27.53 mN/m;加入CuCl₂后溶液表面张力为23.44 mN/m;加入Fe(NO₃)₃后溶液表面张力为21.35 mN/m。在cmc值时,溶液的表面扩展黏度为1.70 mN·s/m,加入NaCl后溶液扩展黏度为2.21 mN·s/m;加入CuCl₂后溶液扩展黏度为2.58 mN·s...     

N-酰基苯丙氨酸钠表面活性剂的合成和性能研究

以十二酰氯、十四酰氯、十六酰氯和苯丙氨酸为原料,肖顿鲍曼法合成了3种不同碳链长度的N-酰基苯丙氨酸钠表面活性剂:N-十二酰基苯丙氨酸钠(C_(12)PheNa)、N-十四酰基苯丙氨酸钠(C_(14)PheNa)和N-十六酰基苯丙氨酸钠(C_(16)PheNa)。通过红外光谱(FTIR)、核磁共振氢谱(~1H NMR)对产物的结构进行了表征。考察了三种表面活性剂的表面活性、泡沫、乳化、润湿性能。结果表明,随着碳链长度的增加(C_(12)～C_(16)),N-酰基苯丙氨酸钠表面活性剂的临界胶束浓度(cmc)由0.15 mmol/L减少至0.02 mmol/L,对应的表面张力(γ_(cmc))由34.56 mN/m降低至31.52 mN/m;随着烷基碳链的增长,乳化性能越好,润湿性能越差;起泡性能随着烷基链的增加呈现先增加后减少,泡沫稳定性随着烷基链的增加而增加。     

一类含氟共聚物表面活性剂的制备与性能

以甲基丙烯酸三氟乙酯(TFEMA)、氯丙烯(AC)为两种基本原料,分别与丙烯酸(AA)或丙烯酰胺(AM)合成两种含氟共聚物表面活性剂。通过红外光谱对其进行结构表征;用凝胶色谱法(GPC)测定其相对分子质量及分布;测定了所得产物的特性黏度、表面活性和发泡能力。结果表明,合成的TFEMA-AA-AC与TFEMA-AM-AC含氟共聚物表面活性剂的特性黏度分别为0.627 2 L/g、0.611 2 L/g;最低表面张力分别为46.4 mN/m、43.8 mN/m;临界胶束浓度分别为7.0×10-3g/L、5.0×10-3g/L。合成的表面活性剂发泡能力较弱,但泡沫稳定性好。同时考察了表面活性剂与无机盐的复配性能,研究表明无机盐NaCl对合成的含氟共聚表面活性剂性能有一定影响。     

Compact Swelling in Bi1.4Pb0.6Sr2Ca2Cu3.6Oy During the Formation of High-Tc Superconducting Phase

Compact swelling in Pb-doped Bi-Sr-Ca-Cu-O superconductor has been studied by observing the effects of the size of calcined powders, volatilization of materials, and sintering of high- T _c (2223) powders. The bulk density increases at the early stage of sintering, for about 20 h, and then decreases. Densification occurs when the low- T _c (2212) phase and a liquid phase exist, whereas dedensification occurs with the formation of the 2223 phase regardless of the presence of the liquid. Gas evolution from specimens does not appear to be responsible for compact swelling. Compact swelling is explained by anisotropic growth of thin, platelike 2223 grains in random orientation. When 2223 grains grow in a preferred direction, compact swelling is suppressed.     

Synthetic routes to nanoscale BxCyNz architectures

B_xC_yN_z nanoscale materials, hybrids of h-BN and graphite, have been recently synthesised using various techniques. Here, we present the latest advances in the synthesis and characterisation of B-C-N nanotubes and nanofibres. In particular, we focus on layered BC₂N, BN, BC and CN_x systems, reviewing their production methods as well as their structural and electronic properties. These materials may find important applications in the fabrication of nanotransistors, robust nanocomposites, conducting polymers, storage components and field emission sources.     

Structure Evolution from Pb(Mg1/3Nb2/3)O3 to La(Mg2/3Nb1/3)O3

The crystal structure of lanthanum-modified lead magnesium niobates having composition (Pb_{1− x} La _x ) (Mg_{(1+ x )/3}-Nb_{(2− x )/3})O₃ with X = 0 to 1 was investigated by X-ray powder diffraction. It was found that the fundamental reflections from perovskite structure remain in the whole range of composition. The superlattice reflections from the A(B'_1/2-B"_1/2)O₃ ordered structure are also well preserved for La content greater than 50 at.%; however, a series of extra peaks of mixing indices appears, with intensities gradually enhanced with the increase of La content. For the complete substitution of Pb by La, a splitting of some reflections can be observed in the diffraction pattern. The results indicate that the crystal structure evolves continuously with the La content, from disordered cubic perovskite of space group Pm 3 m for X = 0, to ordered cubic perovskite of space group Fm 3 m for X = 0.5, distorted cubic perovskite of space group Pa 3 for 0.5 < X < 0.9, and finally to a rhombohedral perovskite, possibly belonging to the space group R 3 , for X ≥ 0.9. In the evolution of structure, a linear reduction of the lattice constant of the perovskite cell from 4.048 to 3.964 Å was observed.     

Microwave Dielectric Properties of CaTiO3-CaAl1/2Nb1/2O3 Ceramics Doped with Li3NbO4

The microwave dielectric properties of CaTi_{1− x} (Al_1/2Nb_1/2) _x O₃ solid solutions (0.3 ≤ x ≤ 0.7) have been investigated. The sintered samples had perovskite structures similar to CaTiO₃. The substitution of Ti⁴⁺ by Al³⁺/Nb⁵⁺ improved the quality factor Q of the sintered specimens. A small addition of Li₃NbO₄ (about 1 wt%) was found to be very effective for lowering sintering temperature of ceramics from 1450–1500° to 1300°C. The composition with x = 0.5 sintered at 1300°C for 5 h revealed excellent dielectric properties, namely, a dielectric constant (ɛ_r) of 48, a Q × f value of 32 100 GHz, and a temperature coefficient of the resonant frequency (τ_f) of −2 ppm/K. Li₃NbO₄ as a sintering additive had no harmful influence on τ_f of ceramics.     

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.     

Dielectric-State Analysis in Solid-Solution Pb(Yb1/2Ta1/2)O3–Pb(Lu1/2Nb1/2)O3

The structure and temperature dependence of complex lead perovskite dielectrics were investigated for the system (1 − x )Pb(Yb_1/2Ta_1/2)O₃– x Pb(Lu_1/2Nb_1/2)O₃. Superlattice reflections for the compositions 0.8 < x < 1.0 were observed by X-ray diffractometry, and the temperature-composition dielectric-state diagram was determined. In the present study, the disordered middle composition, with 0.2 < x < 0.8, showed a diffuse paraelectric–ferroelectric phase transition, whereas the ordered end compositions, with 0 ≤ x < 0.2 and 0.8 < x ≤ 1.0, revealed successive sharp paraelectric–antiferroelectric and weak antiferroelectric–ferroelectric phase transitions. The dielectric state was confirmed by examining the variation of polarization ( P ) with electric field ( E ).