单体N,N-双烯丙基十二胺的合成及其疏水缔合水溶性聚合物的性能

以双烯丙基胺和1-溴代十二烷为原料合成了疏水单体N,N-双烯丙基十二胺(DiAC12),采用前加碱二元单体胶束共聚-后水解法制备三元共聚物丙烯酰胺/丙烯酸钠/N,N-双烯丙基十二胺[P(AM/NaAA/DiAC12)],以芘为荧光探针,利用荧光光谱研究了P(AM/NaAA/DiAC12)在水溶液、1.000 mol/L NaCl水溶液中的缔合行为。结果表明,当疏水单元摩尔分数x(DiAC12)=0.10%～0.40%时,随聚合物浓度、疏水单体用量的增加,芘的I1/I3值减少,缔合作用增加。     

疏水缔合水溶性聚合物P(AM/NaAA/DiAC16)水溶液的黏度行为

采取前加碱二元胶束共聚-后水解法合成了三元疏水缔合水溶性聚合物聚(丙烯酰胺/丙烯酸钠/N,N-双烯丙基十六胺)[P(AM/NaAA/DiAC16)],研究了其水溶液的黏度行为。当x(DiAC16)=0.10%~0.40%时,在30℃、1 mol/LNaCl水溶液中,P(AM/NaAA/DiAC16)的特性黏数[η]、Huggins常数KH、黏均相对分子质量Mη分别为22.59~19.62 dL/g、0.144~0.294和12.49×106~10.47×106g/mol;KH小于0.8,表明其分子内缔合作用较弱。P(AM/NaAA/DiAC16)在矿化度为19 334μg/g盐水溶液中的表观黏度随疏水单体用量的增加而增加,随温度、剪切速率的增加而降低。在NaCl、CaCl2的离子强度分别为1.26×10-3~4.88×10-3mol/kg、1.07×10-4~5.28×10-4mol/kg的水溶液中,P(AM/NaAA/DiAC16)出现盐增黏现象,疏水单体用量越高,盐增黏效应越显著。当ρ(SDS)=0~0.07 g/dL时,P(AM/NaAA/DiAC16)水溶液的表观黏度有明显增加,表明P(AM/NaAA/DiAC16)/SDS分子缔合作用较强。     

P(AM/NaAA/DiAC_n)与十二烷基硫酸钠的相互作用

以芘为荧光探针,用稳态荧光光谱法、粘度法研究了疏水缔合水溶性聚合物聚(丙烯酰胺/丙烯酸钠/N,N-双烯丙基N-烷基胺)[P(AM/NaAA/D iACn)(n=12,14,16)]与阴离子型表面活性剂十二烷基硫酸钠(SDS)的疏水缔合行为。随SDS浓度的增加,I1/I3比值不断减小,得到SDS的临界胶束浓度(cm c)约为8×10-8mol/L。水溶液的表观粘度随SDS质量浓度的增加急剧上升,超过一定浓度后又急剧下降;粘度增加的幅度随疏水链长度增加。结果表明,P(AM/NaAA/D iACn)与SDS可形成混合胶束,发生较强的疏水缔合作用。     

疏水缔合水溶性聚合物P(AM/NaAA/DiAC14)水溶液的黏度行为

采取前加碱二元胶束共聚-共水解法合成了三元疏水缔合水溶性聚合物聚(丙烯酰胺/丙烯酸钠/N,N-双烯丙基十四胺)〔P(AM/NaAA/D iAC14)〕,研究了其水溶液的黏度行为。当x(D iAC14)=0.10%~0.40%时,在30℃、c(NaC l)=1 mo.lL-1水溶液中,P(AM/NaAA/D iAC14)的特性黏数[η]、黏均相对分子质量Mη、Huggins常数KH、平均线团密度ρequ分别为18.88~22.22 dL.g-1、9.98×106~12.24×106g.mol-1、0.117~0.299和0.112~0.132 g.dL-1;KH小于0.8,表明其分子内缔合作用较弱。P(AM/NaAA/D iAC14)在矿化度为19 334μg.g-1盐水溶液中的表观黏度随疏水单体摩尔分数的增加而增加,随温度、剪切速率的增加而降低。在NaC、lCaC l2的离子强度分别为1.26×10-3~4.88×10-3mol.kg-1、1.073×10-4~5.28×10-4mol.kg-1的水溶液中,P(AM/NaAA/D iAC14)出现盐增黏现象,疏水单体摩尔分数越大,盐增黏效应越显著。随疏水单体摩尔分数的增加,临界缔合质量浓度(CAC)降低;与后加的十二烷基硫酸钠(SDS)〔ρ(SDS)=0~0.07 g.dL-1〕的疏水缔合作用增强,黏度增加的幅度增大。     

孪尾疏水缔合丙烯酰胺/丙烯酸钠/N,N-二己基丙烯酰胺共聚物制备条件的研究

采取先加碱共聚-共水解的方法合成了孪尾疏水缔合丙烯酰胺/丙烯酸钠/N,N-二己基丙烯酰胺共聚物[P(AM/NaAA/DiC6AM)],用傅里叶变换光谱、1H-核磁共振及容量分析法对其结构进行了表征.反应10 h转化率可达92%,之后增加缓慢.水解度主要受水解时间的影响,受疏水单元摩尔分数的影响较小.还研究了疏水单元摩尔分数、总单体质量浓度、DM质量浓度、(NH4)2S2O8质量浓度、温度、SMR对P(AM/NaAA/DiC6AM)水溶液的表观黏度的影响.     

新型疏水缔合水溶性聚合物的合成及溶液性能研究

以四甲基乙二胺分别与溴代正十四烷/溴代正十六烷反应得到单季铵盐,再与溴丙烯反应即得到2种新型疏水单体十四烷基烯丙基二溴化四甲基乙二铵(C14PDBTMN)和十六烷基烯丙基二溴化四甲基乙二铵(C16PDBTMN)。用1HNMR和IR对单体结构进行表征,结果表明为目标化合物。以C16PDBTMN为功能性单体,和丙烯酰胺进行共聚得到新型疏水缔合物P(C16PDBTMN/AM),研究表明,新型疏水缔合物具有其独特的抗盐、抗剪切性能。     

孪尾疏水缔合丙烯酰胺/丙烯酸钠/N,N-二丁基丙烯酰胺共聚物的合成与性能

以十二烷基硫酸钠(SDS)为表面活性剂,丙烯酰胺(AM)的水溶液为连续相,N,N-二丁基丙烯酰胺(DiC4AM)为分散相,采取先加碱共聚-共水解的方法合成了孪尾疏水缔合水溶性聚合物聚(丙烯酰胺/丙烯酸钠/N,N-二丁基丙烯酰胺)[P(AM/NaAA/DiC4AM)]。用FT IR1、H NMR对其结构、组成进行了表征和测定。用稀释外推粘度法测定了共聚物的特性粘数[η]、Huggins常数KH。用芘荧光探针法及表观粘度法研究了大分子链间的疏水缔合作用,考察了疏水单体用量对其水溶液表观粘度的影响。     

荧光探针研究P(AM/NaAA/DiC8AM)在水溶液中的缔合行为

以芘为荧光探针研究了孪尾疏水缔合水溶性聚合物聚(丙烯酰胺/丙烯酸钠/N,N-二正辛基丙烯酰胺)[P(AM/NaAA/D iC8AM)]在二次蒸馏水、c(NaC l)=1 mol/L水溶液中的荧光光谱。当x(疏水单体)=0.10%~0.40%、表面活性剂与疏水单体的摩尔比(SMR)为20~70、x(丙烯酸)=20%~40%、ρ(聚合物)=5~50 g/mL时,I1/I3值为1.76~1.25。表明疏水基团间存在疏水缔合相互作用,且随疏水单体用量、聚合物质量浓度及介质极性的增加,和丙烯酸用量、SMR值的减少,芘的I1/I3值降低,疏水缔合作用增强。     

新型孪尾疏水改性聚合物／表面活性剂的溶液性能研究

采用前加碱胶束共聚-共水解法制备了丙烯酰胺、丙烯酸钠和新型孪尾疏水单体N,N-二正辛基丙烯酰胺的三元共聚物P(AM/NaAA/DiC8AM),利用FTIR和1H-NMR确定了共聚物的结构,测定了共聚物/表面活性剂复合体系水溶液的表观粘度,研究了表面活性剂种类、温度、电解质、剪切速率等因素对复合体系溶液表观粘度的影响。P(AM/NaAA/DiC8AM)/SDS和P(AM/NaAA/DiC8AM)/CTAB复合体系的溶液表观粘度与HPAM共聚物溶液相比有明显的提高,疏水单体含量越大,复合体系的溶液表观粘度越大,且其溶液具有一定的耐温、耐盐和抗剪切性。     

表面活性剂对孪尾缔合聚合物水溶液表观黏度的影响

用黏度法研究了孪尾疏水缔合水溶性聚合物聚（丙烯酰胺／丙烯酸钠／N,N-二己基丙烯酰胺）[P（AM／NaAA／DiC6AM）]与十二烷基硫酸钠（SDS）、十六烷基三甲基溴化铵（CRAB）、OP-10的相互作用。结果表明,水溶液的表观黏度随SDS、CTAB质量浓度的增加急剧上升,超过一定浓度后水溶液黏度又急剧下降;黏度上升的幅度随疏水单体用量的增加、表面活性剂与疏水单体的摩尔比率（SMR值）的减小而增大;随水解度的增加,黏度上升的幅度较小。P（AM／NaAA／DiC6AM）的临界缔合浓度cac约为30g/mL,当加入SDS、CTAB时,能显著地降低。随OP-10质量浓度的增加,水溶液表观黏度几乎不变。表明P（AM／NaAA／DRAM）与SDS、CTAB的疏水缔合作用较强,而与OP-10的疏水缔合作用较弱。     

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.