【作者】 辛霞；

【导师】 徐桂英；

【作者基本信息】 山东大学 ， 物理化学， 2008， 博士

【摘要】 许多水溶性高分子因其具有生物相容性和环境友好性而成为当今最受重视的材料之一,同时水溶性高分子与表面活性剂混合体系可以相互作用形成复合物,其水溶液的许多特性常常优于任一纯组分体系的性质,所以水溶性高分子溶液及其与表面活性剂的混合体系在洗涤剂、涂料、化妆品、食物、医药、生物、纺织、感光材料、采矿以及油田开发等行业中已得到非常广泛的应用。因此,关于水溶性高分子的物化性质及其与表面活性剂相互作用的研究是多年来人们一直十分感兴趣的研究课题。近年来,很多课题组已经采用各种手段对聚氧乙烯（PEO）、聚乙二醇（PEG）、聚乙烯吡咯烷酮（PVP）、聚丙烯酰胺（PAM）等水溶性高分子的物化性质及其在溶液中与各种表面活性剂分子间的相互作用做了大量研究。本论文不仅通过表面张力、界面扩张流变、体相流变、稳态荧光和电镜等技术研究了本实验室合成的具有星状结构的嵌段聚醚AP432的物理化学性质及其与羧酸盐表面活性剂油酸钠(C₁₇H₃₃COONa)之间的相互作用,并与另一种非离子型水溶性聚合物PVP与C₁₇H₃₃COONa之间的相互作用进行了比较;而且,研究了阴离子型聚电解质部分水解聚丙烯酰胺（HPAM）和C₁₇H₃₃COONa、硬脂酸钠(C₁₇H₃₅COONa)之间的相互作用,讨论了混合体系的浓度依赖性和抗温抗盐性。研究内容共分为五部分:论文的第一部分概述了水溶性高分子和表面活性剂的基本性质和应用,阐明了水溶性高分子和表面活性剂相互作用的重要意义。论文的第二部分通过表面张力、荧光、光散射和透射电镜（TEM）等方法研究了本实验室合成的星状嵌段聚醚AP432的聚集行为,并对比研究了和线型嵌段聚醚L64的聚集行为。结果表明,AP432降低水的表面张力的效率和效能都高于L64,且AP432在空气/水界面上的饱和吸附量高于L64,而占据的分子最小截面积低于L64,说明AP432分子在空气/水界面上的排列要比L64分子紧密。荧光光谱实验结果表明,星状AP432的I₁/I₃值远低于线型L64,同时也证明了AP432胶束中的分子排列比L64要紧密。TEM观察表明,随着AP432浓度增加,形成的胶束尺寸逐渐增大;而L64随着浓度增加胶束尺寸几乎不变,倾向于形成新的胶束。论文的第三部分主要通过UV-vis-NIR吸收光谱、拉曼光谱、TEM和高分辨电镜（HRTEM）电镜等方法研究了星状嵌段聚醚AP432和线型嵌段聚醚F127及L64分散碳纳米管（CNTs）的能力,比较了它们之间由于分子结构和分子量不同对CNTs分散能力的差异。结果表明,星状聚醚AP432和线型聚醚F127都具有分散碳纳米管的能力,而和AP432具有相似EO%含量的另一种线型聚醚L64却不能分散碳纳米管。与F127相比,AP432在较低浓度下就表现出可观的分散CNTs的能力,这是由于星状的AP432分子比线型的F127分子能够产生更高空间位阻效应,同时由于AP432分子较F127具有较短的疏水链段,无法和多根碳管相互作用,所以它比线型F127分子更容易分散得到以单根状态存在的CNTs。当AP432和F127的浓度较高时,胶束的形成容易导致碳管的聚沉,这一现象在CNTs/AP432分散体系中更为明显,这是因为与F127相比,AP432具有较低的cmc值和较大的胶束尺寸。根据AP432和F127对碳纳米管不同的分散效果进一步验证了前人提出的聚醚分散碳纳米管的机制:即聚醚的疏水链PO基团与碳纳米管之间通过疏水作用吸附在碳纳米管的侧壁上,而两端亲水的EO基团伸展于水溶液中从而阻止碳纳米管的相互聚集。论文的第四部分共分为两小节。第一节主要通过表面张力、荧光、界面流变和TEM等方法比较研究了星状聚醚AP432和和L64与C₁₇H₃₃COONa之间的相互作用,分析了AP432和L64的分子结构和分子量对相互作用的影响。结果表明,AP432和L64都能够和C₁₇H₃₃COONa形成混合胶束,且在任意比例时混合体系的cmc和γ_cmc都介于两单一体系之间,TEM结果表明,在研究的浓度范围内AP432/C₁₇H₃₃COONa和L64/C₁₇H₃₃COONa复配体系都形成了球状胶束。扩张黏弹性研究表明,无论单一的AP432、L64或C₁₇H₃₃COONa水溶液还是AP432/C₁₇H₃₃COONa、L64/C₁₇H₃₃COONa混合体系,扩张模量均随扩张频率的增加而升高,且随嵌段聚醚浓度增加,体系的扩张模量都出现一最大值。第二节主要利用表面张力和Langmuir槽技术考察了PVP和C₁₇H₃₃COONa混合溶液在空气/水界面上的表面张力和扩张粘弹性质,并且研究了外加盐NaCl和NaI对C₁₇H₃₃COONa与PVP之间相互作用的影响。结果表明PVP存在时C₁₇H₃₃COONa溶液的表面张力等温线出现两个明显的转折点（T₁和T₂）,且随着PVP浓度的增大,T₁基本不变,而T₂却逐渐增大。少量的NaCl和NaI能使C₁₇H₃₃COONa的表面活性大大增加,且NaCl降低C₁₇H₃₃COONa溶液CMC的程度略大于NaI。另外,NaCl和NaI存在时能促进C₁₇H₃₃COONa/PVP复合物的形成;且在NaCl存在时,同样量的PVP能够比在NaI存在时结合更多的C₁₇H₃₃COONa分子。论文的第五部分也分为两小节。第一节主要采用流变学方法研究了HPAM与C₁₇H₃₃COONa之间的相互作用,讨论了C₁₇H₃₃COONa和HPAM的浓度对混合体系流变性质的影响。结果表明,C₁₇H₃₃COONa浓度较低时HPAM/C₁₇H₃₃COONa混合体系的粘度出现一最大值,且随着HPAM溶液浓度增加,体系粘度达到最大值时所需要的C₁₇H₃₃COONa浓度逐渐增加。含有高浓度C₁₇H₃₃COONa时HPAM溶液的表观粘度随着C₁₇H₃₃COONa浓度增加呈单调下降的趋势,说明HPAM体系的网络结构逐渐减弱,且高浓度的HPAM体系需要更多的C₁₇H₃₃COONa来破坏HPAM的网络结构。第二节采用流变学方法研究了HPAM与C₁₇H₃₅COONa的相互作用,并考察了无机盐CaCl₂、温度和pH值对HPAM/C₁₇H₃₅COONa混合体系流变行为的影响。结果表明,CaCl₂的加入导致混合体系中HPAM分子极性基团的水化层压缩,大分子链塌陷,影响了HPAM和C₁₇H₃₅COONa之间的相互作用,使得体系的粘度降低。温度的升高使HPAM分子脱水、导致HPAM链间的缠绕减弱,分子间的摩擦力减小,从而结构破坏,使得HPAM分子塌陷,也导致了体系的粘度都下降。而溶液pH的变化使得HPAM和C₁₇H₃₅COONa分子的羧基基团离子化程度改变,也影响了HPAM和C₁₇H₃₅COONa之间的相互作用。更多还原

【Abstract】 Nowadays,water-soluble polymer is one of the most important polymers because of their biocompatibility and environmently friendly.Moreover.surfactants and water-soluble polymers can interaction with each other to form complexs,they usually displays intriguing and fascinating features,which is different from polymer or surfactant.Thus,the studies on the physicochemical properties of water-soluble polymer and its interaction with surfactant have attracted increasing attention because of their complex behaviors and potential applications in detergents,paints,cosmetics. food,pharmaceuticals,coatings and enhanced oil recovery,etc.In the past decades,a number of studies have focused on the physicochemical properties of water-soluble neutral polymers like poly（ethylene oxide）（PEO）. Polyethylene glycol（PEG）,poly-（vinylpyrrolidone）（PVP）and polyacrylamine（PAM） and their interactions with surfactant.In this thesis,the interaction between a star-like amphiphilic block copolymer（denoted as AP432,which was synthesized via anionic polymerization in our lab）and carboxylate surfactant sodium oleate(C₁₇H₃₃COONa) is studied by surface tension,oscillating barrier,steady-state fluorescence measurements and transmission electron microscopy（TEM）.etc.For comparision. parallel measurements have also been made on the interaction between PVP and sodium oleate.Moreover,in order to finish the programme of oil field,the interaction between HPAM and C₁₇H₃₃COONa.sodium stearate(C₁₇H₃₅COONa)were investigated by rheological measurements.The rheological properties of HPAM/C₁₇H₃₃COONa as a function of concentration and the heat and salt tolerances of HPAM/C₁₇H₃₅COONa system were studied.This thesis is divided into five parts:In the first section,the properties and applications of water-soluble polymers and surfactants and the study progress on the interaction between surfactant and water-soluble polymer are summarized.In the second section,the interface properties and the aggregation behavior of AP432,in aqueous solutions were investigated by surface tension,steady-state fluorescence,dynamic light scattering（DLS）and TEM.For comparison.a commercially available linear amphiphilic PEO-PPO-PEO block copolymer, Pluronics L64,which has a similar PEO fraction to AP432,was also studied.It is found that both the efficiency and the effectiveness of AP432 to lower the surface tension of water are higher than those of L64,theΓ_maxvalue of AP432 is higher and the A_minvalue of AP432 is lower than that of L64.From fluorescence measurement,it can be conclude that the I₁/I₃ value of AP432 is much lower than that of L64 at high concentration,indicating that the micelles formed by AP432 are more compact than that of L64.TEM observations reveal that the molecules of AP432 are inclined to aggregate more compact and more molecules can aggegated to form one micelle when the concentration is increased.But for L64.once the micelles are formed,more molecules can form another micelle or combined together with increasing of L64 concentration.In the third section,the ability of dispersing carbon nanotubes（CNTs）in aqueous solutions by AP432 was investigated in detail by UV-vis-NIR,Raman spectra,TEM and HRTEM observations.For comparison,two commercially available linear amphiphilic PEO-PPO-PEO tri-block copolymers,Pluronics L64 and F127 were also studied.From the experiments,it was found that AP432 and F127 can get good CNTs dispersions stable for months while it was not the case for L64.The star-like AP432 with five branches could disperse CNTs efficiently at much lower concentration and has advantages to disperse CNTs in individuals or smaller bundles compared with the linear F127,although it has a smaller molecular weight and shorter terminal EO groups.Increasing concentration of AP432 or F127 would disperse more CNTs,but the flocculation of dispersed CNTs was observed at high copolymer concentrations,which may be related to the free micelles formed by AP432 or F127 around CNTs.At high concentration of AP432.free micelles began to form which caused a subsequent of the dispersed tubes.Under the HRTEM analysis and other observations used in our measurements,the mechanism of dispersing CNTs by different copolymers can be rationalized,that is.when mixed with CNTs,the PO groups would interact with the sidewall of CNTs while the EO groups extend into water and hence create a so-called steric repulsion. The fourth section divides into two parts.In part one,the interaction between AP432 and an anionic surfactantC₁₇H₃₃COONa in aqueous solutions was investigated by surface tension,oscillating barrier,steady-state fluorescence measurements and TEM.For comparison,the interaction between Pluronics L64 and C₁₇H₃₃COONa was also studied.AP432 and C₁₇H₃₃COONa could form mixed micelles in aqueous solutions and the cmc values were between that of individual AP432（L64）and C₁₇H₃₃COONa,as revealed by surface tension measurements.TEM observations also reveal that both AP432/C₁₇H₃₃COONa and L64/C₁₇H₃₃COONa systems form mixed spherical micelles.Moreover,the dilational modulus increases gradually with the increase of dilational frequency and the dilational moduli pass through the maximum values with increasing concentration not only for the pure AP432、L64 and C₁₇H₃₃COONa solutions,but also for AP432/C₁₇H₃₃COONa and L64/C₁₇H₃₃COONa systems.In second part,the study of the interaction between PVP and C₁₇H₃₃COONa in aqueous solution in the presence of sodium halide（NaX:X=Cl,I）is investigated by surface tension and the oscillating barriers measurements.It can be seen that two inflection points were observed when PVP is added,implying the interaction between C₁₇H₃₃COONa and PVP occurs.An increase of PVP concentration shifts T₂ values toward higher C₁₇H₃₃COONa concentration,indicating that more C₁₇H₃₃COONa molecules bind on the PVP chains to form PVP/C₁₇H₃₃COONa complexes.It also can be concluded that the addition of NaX can decrease the CMC of C₁₇H₃₃COONa solutions and NaCl has more effect than NaI on decreasing the CMC of C₁₇H₃₃COONa solutions.An addition of NaX also affects the binding cooperativity between C₁₇H₃₃COONa and PVP,and the higher NaX concentration corresponds to the higher binding cooperativity.Moreover,NaCl is more efficient than NaI in promoting the interaction between C₁₇H₃₃COONa and PVP.The fifth section also divides into two parts.In part one.the interaction between HPAM and C₁₇H₃₃COONa was investigated by rheological measurements and the influences of the concentrations of HPAM and C₁₇H₃₃COONa on the rheological properties of mixed systems were also studied.With increasing amount of C₁₇H₃₃COONa.the shear viscosity of the system first shows an increase due to interpolymer cross-linking through hydrogen bonding between C₁₇H₃₃COONa and HPAM.It can be noted that the concentration of C₁₇H₃₃COONa needed to get the maximum viscosity increases for the higher HPAM concentration systems.With further increase of C₁₇H₃₃COONa concentration,a drastic decrease of viscosity is induced by the breakdown of the cross-linking network due to an increasing of ionic strength,which would make the coil of HPAM shrink.Also,to lower the viscosity of the sample to similar extent,higher concentration of C₁₇H₃₃COONa is required to make HPAM molecule shrink for higher concentration of HPAM.In second part.the effects of CaCl₂,temperature and pH on the HPAM/C₁₇H₃₅COONa systems were investigated via steady-flow and oscillatory experiments.The results reveal that addition of CaCl₂ causes the double layer of HPAM to collapse,resulting in loss of structure and a corresponding loss of viscosity and shear thinning behavior.Moreover. the increasing of temperature can give rise to crimple of HPAM molecules due to its dehydrating and destruction of the associational structure.As a consequence,the viscosities of systems also decrease.With pH increasing,carboxyl groups of the HPAM and C₁₇H₃₅COONa molecular chains ionize much more and the resultant electrostatic repulsion cause stretching of the chains,resulting in the decrease of intra-molecular associations of HPAM and the increase of interaction between HPAM and C₁₇H₃₅COONa.更多还原