聚(丙烯酰胺-丙烯酸)/聚(丙烯酰胺-二甲基二烯丙基氯化铵)聚电解质复合溶液动态光散射研究

通过动态光散射、粘度和透光率测定，研究了聚（丙烯酰胺 丙烯酸）［Ｐ（ＡＭ ＡＡ）］／聚（丙烯酰胺 二甲基二烯丙基氯化铵）［Ｐ（ＡＭ ＤＭＤＡＡＣ）］聚电解质复合溶液的结构和性能．结果表明，Ｐ（ＡＭ ＡＡ）与Ｐ（ＡＭ ＤＭＤＡＡＣ）复合比、溶液浓度和氯化钠用量影响溶液中复合物的构象和流体力学半径．Ｐ（ＡＭ ＡＡ）与Ｐ（ＡＭ ＤＭＤＡＡＣ）分子链间适度的库仑相互作用，可形成均相Ｐ（ＡＭ ＡＡ）／Ｐ（ＡＭ ＤＭＤＡＡＣ）聚电解质复合溶液，复合物具有较伸展的构象和较大的流体力学半径，因而溶液粘度较高．Ｐ（ＡＭ ＡＡ）与Ｐ（ＡＭ ＤＭＤＡＡＣ）分子链间过强的库仑相互作用或小分子电解质的屏蔽作用，可使复合物构象卷曲，结构紧缩，流体力学半径减小，甚至产生相分离，导致溶液粘度降低．     

甲基丙烯酸甲酯 - 甲基丙烯酸共聚物/梯形聚苯基硅倍半氧烷原位共混体系的性能研究

甲基丙烯酸甲酯 甲基丙烯酸共聚物（Ｐ（ＭＭＡ ＭＡＡ））与低分子量或高分子量梯形聚苯基硅倍半氧烷（ＰＰＳＱ）的共混物经原位聚合法制成．用光学透明法、荧光光谱、ＤＳＣ等技术研究了该共混体系的相容性及组分间的相互作用及结构转变．结果表明，当ＰＰＳＱ含量较小时，由于ＰＰＳＱ与Ｐ（ＭＭＡ ＭＡＡ）间存在着较强的氢键作用，该共混体系在一定配比下相容，且低分子量ＰＰＳＱ与Ｐ（ＭＭＡ ＭＡＡ）间的相容性较好．当ＰＰＳＱ的含量≤１％时，ＰＰＳＱ的加入对该共混物的Ｔｇ影响不大，但其Ｔｆ随ＰＰＳＱ含量增加而增大．此外，还测试了Ｐ（ＭＭＡ ＭＡＡ）／ＰＰＳＱ原位共混物的硬度及冲击强度．     

聚（丙烯酰胺—丙烯酸）／聚（丙烯酰胺—二甲基二烯丙基氯化铵）聚电解质复…

通过动态光散射、粘度和透光率测定，研究了聚（丙烯酰胺－丙烯酸）［Ｐ（ＡＭ－ＡＡ）］／聚（丙烯酰胺－二甲基二烯丙基氯化铵）［Ｐ（ＡＭ－ＤＭＤＡＡＣ）］聚电解质复合溶液的结构和性能。结果表明，Ｐ（ＡＭ－ＡＡ）与Ｐ（ＡＭ－ＤＭＤＡＡＣ）复合比、溶液浓度和氯化钠用量影响溶液中复合物的构象和流体力学半径。Ｐ（ＡＭ－ＡＡ）与Ｐ（ＡＭ－ＤＭＤＡＡＣ）分子链间适度的库仑相互作用，可形成均相Ｐ（ＡＭ－ＡＡ）／Ｐ（Ａ     

乙烯系自由基聚合阻聚效应（ⅩⅧ）：哌啶氮氧自由基氨基硫…

本文研究了３种１－（芳酰基）－４［４＇－（２，２，６，６－四甲基哌啶）－１－氧自由基］氨基硫脲化合物（ＡＴＳＣＰＯ）分别同通用阻聚剂（ＣＩＨ），如对苯二酚（ＨＱ），苯醌（ＢＱ），吩噻嗪（ＰＴ）及二乙羟胺（ＤＥＨＡ）组成的混合阻聚剂对ＡＩＢＮ引发的ＭＭＡ自由基聚合的影响，研究结果表明：当［ＡＴＳＣＰＰ］／ＣＩＨ＝５：１时，除ＡＴＳＣＰＯ－ＢＱ外，其余阻聚效果均较ＡＴＳＣＰＯ和ＣＩＨ单独用作阻聚剂时高     

聚醋酸乙烯酯与铜（Ⅱ）离子的配位反应及其催化作用

以ＥＳＲ、ＵＶ和ＩＲ表征Ｃｕ（２＋）离子与ＰＶＡＣ的配位反应。根据ＣＵＣｌ２·２Ｈ２Ｏ乙醇溶液与ＰＶＡｃ－ＣｕＣｌ２·２Ｈ２Ｏ乙醇溶液的电导率差值随Ｃｕ（２＋）离子摩尔浓度变化的明显转析点得知，１个Ｃｕ（２＋）离子大约能与ＰＶＡｃ４个链节单元配位。证实ＭＭＡ在Ｃｕ（Ⅱ）－ＰＶＡｃ配合物／Ｎａ２ＳＯ３体系的聚合体是无规ＰＭＭＡ，得率为７０％。讨论了ＭＭＡ在Ｃｕ（Ⅱ）－ＰＶＡｃ配合物／Ｎａ２ＳＯ３体系络合催化引发下的游离基反应历程。     

PVC/PBD-b-PMMA共混体系相容性的研究

采用ＤＭＡ和ＴＥＭ系统研究了聚丁二烯－聚甲基丙烯酸甲酯的嵌段共聚物（ＰＢＤ－ｂ－ＰＭＭＡ）与聚氯乙烯（ＰＶＣ）共混体系的相容性问题。结果表明：ＰＶＣ／ＰＢＤ－ｂ－ＰＭＭＡ共混体系具有部分相溶性。相容的程度与共混体系的组成、组分聚合物的分子量以及共聚物中ＰＢＤ和ＰＭＭＡ嵌段的比例密切相关。     

聚环氧乙烷为支链的两亲共聚物的表征及性能

用端基带有甲基丙烯酸酯的聚环氧乙烷大分子单体（ＰＥＯ—ＭＡ）分别与小分子单体苯乙烯（Ｓ）、甲基丙烯酸甲酯（ＭＭＡ）、丙烯酸甲酯（ＭＡ）溶液自由基共聚合得到了三种具有不同主链结构的以聚环氧乙烷（ＰＥＯ）为支链的两亲接枝嵌段共聚物（分别简写为：ＰＳ─ｇ─ＰＥＯ，ＰＭＭＡ─ｇ─ＰＥＯ，ＰＭＡ─ｇ─ＰＥＯ）．用ＧＰＣ、ＩＲ、１Ｈ─ＮＭＲ、ＷＡＸＤ和ＤＳＣ对其结构进行了表征．研究了接校共聚物的结晶性能、乳化性能以及在Ｗｉｌｌｉａｍｓｏｎ反应中相转移催化作用．结果表明，不同主链结构有不同的结晶度，并随支链ＰＥＯ含量的增加，分子量的增大而提高；其乳化体积和相转移催化反应的转化率均随着共聚物浓度的增加、支链ＰＥＯ含量的增人而增大，随支链ＰＥＯ分子量的提高而减小．     

1,4—双（氯甲基）—2—甲氧基—5—壬氧基苯的均聚和共聚研究

以１，４－双（氯甲基）－２，５一二甲基苯（ＢＣＭＤＭＢ）和１，４－双氯甲基－２－甲氧基－５－壬氧基苯（ＢＣＭＭＯＮＯＢ）为单体，采用脱氯化氢法，合成了聚（２，５－二甲基）对亚苯基亚乙烯（ＰＤＭＰＶ）和聚（２－甲氧基－５－壬氧基）对亚苯基亚乙烯（ＰＭＯＮＯＰＶ）；并对ＢＣＭＤＭＢ和ＢＣＭＭＯＮＯＢ的共聚进行了研究。结果表明，适宜的反应条件为：碱与单体的摩尔比为２０∶１，在室温下聚合时间为３０ｈ，碱的ｐＨ＝１４时产率最高。用ＩＲ、１Ｈ－ＮＭＲ、ＵＶ—Ｖｉｓ对聚合物进行了表征。     

聚环氧氯丙烷聚氨酯／聚甲基丙烯酸甲酯互穿网络聚合物的相容性与力学性能

用同步法合成了聚环氧氯丙烷聚氨酯／聚甲基丙烯酸甲酯互穿网络聚合物［ＰＵ（ＰＥＣＨ）／ＰＭＭＡＩＰＮ］，调节ＩＰＮ中两组分组成比制备出由完全弹性体、增强弹性体、增韧塑料到脆性塑料多种高聚物合金材料．用ＤＳＣ、动态力学谱、ＴＥＭ对ＩＰＮ的研究结果表明，ＰＵ（ＰＥＣＨ）／ＰＭＭＡＩＰＮ的两组分是完全相容的；同时对各种组成比的ＩＰＮ材料进行力学性能测试，用相容性ＩＰＮ中互穿、缠结结构解释其力学行为，并用ＳＥＭ对断面形貌进行了观察解释．     

4—（H酸偶氮）—1—苯基—3—甲基吡唑酮光度法测定铝

研究了新试剂４－（Ｈ酸偶氮）－１－苯基－３－甲基吡唑酮（ＨＡＰＭＰ）与铝的显色反应，在ｐＨ４．６的ＨＡｃ－ＮａＡｃ缓冲介质中，ＣＴＭＡＢ存在下，ＨＡＰＭＰ和Ａｌ（Ⅲ）反应生成２：１红色络合物，铝的含量在０￣３．５μｇ／２５ｍＬ内符合比尔定律，方法已用于天然水样中铝的测定。     

Fluorescence probe studies on the complexation between poly(methacrylic acid) and poly(N, N-diethylacrylamide)

The complexation between poly(methacrylic acid) (PMAA) and poly(N, N-diethylacrylamide) (PDEAM) in aqueous phase was studied by UV-vis and fluorescence probe techniques. It was demonstrated that the complexation of PMAA with PDEAM occurs within a pH range of 1-6.5 and along with the complexation, the conformation of PMAA changed from a hypercoiled to a loose coiled form. The complex ratio between the two polymers is 1:1 (PMAA:PDEAM, in monomer unit). Salt effect studies showed that the complexation occurred due to formation of hydrogen bonds between the two polymers. Based upon these conclusions and the "compact micelle-like structure" for PMAA at low pH, a "ladder" model was proposed for the structure of PMAA-PDEAM complex formed at low pH.     

Interpolymer complex formation between helical poly(L-proline) and random-coil poly(methacrylic acid) through hydrogen bonding

Interpolymer complex formation between poly(L -proline) (PLP) with helical structure and poly(methacrylic acid) (PMAA) with random-coil structure through hydrogen bonding in aqueous medium has been studied by several experimental techniques, e.g., viscometry, turbidimetry, potentiometry, conductometry, scanning electron microscopy, and x-ray diffraction methods. The decreases in reduced viscosity of the solution on addition of an increasing quantity of PLP to a constant amount of PMAA reveals the formation of a complex between PLP and PMAA. The minimum in reduced viscosity at a unit-mole ratio [PLP]/[PMAA] = 1.0 suggests a 1 : 1 complex formation. A distinct change in the curves for turbidity, pH, and conductance versus [PLP]/[PMAA] supports this conclusion. A scanning electron micrograph for the 1 : 1 PLP–PMAA complexes shows that the PLP/PMAA complex has the shape of entangled long fibers. An x-ray diffraction pattern for the PLP/PMAA complexes gives no diffraction patterns which appear in pure PLP, indicating the destruction of the helical structure of PLP due to the interpolymer complexation. Mixtures of PMAA with poly(γ-hydroxy-L -proline) (PHLP) which has a similar conformation as PLP, but involves intra- or intermolecular hydrogen bonds, has also been investigated by vicometry measurements. The reduced viscosity of a solution of the mixed polymers increases with increasing [PHLP], indicating no complex formation. All the results reveal that the magnitude and the nature of the forces acting in the polymers play an important role in interpolymer complexation.     

Studies on interpolymer self-organisation behaviour of protoporphyrin IX bound poly(carboxylic acid)s with complimentary polymers by means of fluorescence techniques

Covalently bound protoporphyrin IX was used as a fluorophore to investigate the interpolymer complex formation between the poly(carboxylic acid)s, PMAA/PAA and poly(N-vinyl pyrrolidone), PVP, poly(ethylene oxide), PEO or poly(ethylene glycol), PEG. Absorption and emission spectral properties of protoporphyrin IX bound to PAA, PMAA and PVP have been studied. Protoporphyrin IX in poly(MAA-co-PPIX) was found to be present in the dimer or higher aggregated form at low pH due to the environmental restriction imposed by the polymer whereas in the case of poly(AA-co-PPIX) and poly(VP-co-PPIX), PPIX exists in monomeric form. The fluorescence intensity and lifetime of PPIX bound to poly(carboxylic acid)s increase on complexation through hydrogen bonding with PVP, PEO and PEG due to the displacement of water molecules in the vicinity of the PPIX. Poly(MAA-co-PPIX) shows longer fluorescence lifetime due to the more compact interpolymer complexation as compared to poly(AA-co-PPIX) due to the enhanced hydrophobicity of PMAA. Poly(VP-co-PPIX) shows a decrease in the fluorescence lifetime on complexation with PMAA or PAA due to the hydrophilic and microgel like environment of the fluorophore bound to PVP. The contrasting behaviour of the same polymer adduct with respect to the site of the fluorophore is interpreted to be due to the solvent structure which determines the environment of the fluorophore.     

Preparation and complexation of an A–B–A type triblock copolymer consisting of helical poly(L-proline) and random-coil poly(ethylene oxide)

By using L -proline N-carboxyanhydride (LPNCA) and amino-group terminated poly(ethylene oxide) (ATPEO), an A–B–A–type [A = poly(L -proline) (PLP), B = poly(ethylene oxide) (PEO)] triblock copolymer (POP) was prepared which is water-soluble. In the POP, A = PLP is helical, and B = PEO is random coil. From the observations of the NMR spectra, specific optical rotation, and x-ray diffraction of the POP, it was found that the PLP component of the POP exists nearly as Form II PLP with trans-configuration, and interferes the crystal growth of PEO component, in solid state. With the addition of PMAA into an aqueous POP solution, dramatic decreases of reduced viscosity and pH are observed until the unit-mole-concentration-ratio (UMCR) [PMAA]/[POP] reaches its value of unity, while a distinct increase in turbidity appears. This shows a 1 : 1 interpolymer complex formation between PMAA and POP in aqueous medium through hydrogen bonding. The curves of viscosity, pH, and turbidity versus UMCR [PMAA]/[POP] show breaks at [PMAA]/[POP] = 0.3, suggesting the selective complexation of PLP component (ca. 30 unit-mol %) of POP with PMAA. The x-ray diffraction curve of the complex POP/PMAA shows entirely no diffraction patterns, indicating that the ordered POP structure (mainly due to that of PLP component) is completely destroyed owing to the complexation between POP and PMAA.     

N-乙烯基咔唑标记甲基丙烯酸-苊烯共聚物的荧光特性

合成了苊烯(ACE)含量依次为4.3、7.5、15.1及20.8 mol％的N 乙烯基咔唑(NVCz)标记甲基丙烯酸(MAA) 苊烯共聚物(PMAA ACE/NVCz）和ACE含量仅为0.5 mol％的ACE MAA共聚物（PMAA ACE）,研究了各共聚物在稀水溶液中的荧光行为和pH、表面活性剂等对共聚物荧光特性的影响.实验发现:在酸性介质中共聚物的压缩线团构象使激发态缔合物荧光相对增强,ACE到NVCz能量转移效率增加;碱性介质中共聚物构象相对松散,ACE到NVCz能量转移效率降低,因此荧光光谱中NVCz特征几乎消失.阴离子表面活性剂十二烷基磺酸钠(SDS),阳离子表面活性剂十六烷基三甲基溴化铵(AHTB)以及中性表面活性剂吐温80的引入使共聚物在酸性介质中的单体荧光特征增强,ACE到NVCz的能量转移效率下降;在碱性介质中引入AHTB部分中和了共聚物链上的负电荷,使共聚物构象重新卷曲,ACE到NVCz的能量转移效率提高,荧光光谱中NVCz特征重新出现,ACE单体荧光特征相应减少;在碱性介质中引入SDS以及吐温80对共聚物荧光光谱影响不大.     

温度/pH敏感性P(MAA-g-DEAM)共聚物水溶液的相行为

利用大分子单体技术通过自由基共聚法合成了由甲基丙烯酸(MAA)和N, N-二乙基丙烯酰胺(DEAM)组成的几种不同组成的P(MAA-g-DEAM)接枝共聚物.通过UV-Vis 透光率的测定和荧光探针技术, 对共聚物水溶液的相行为进行了研究. 研究表明, 此接枝共聚物具有相互独立的温度和pH 敏感性；几种组成不同的P(MAA-g-DEAM)接枝共聚物具有基本相同的低临界溶解温度(LCST)；它们的临界相变pH与接枝共聚物的组成有关, 温敏性PDEAM 枝链的接枝率越高, 其临界相变pH 越高. pH > 5.5 时, 接枝共聚物的主链是一种较为松散的线团构象；pH < 5.5 时, 接枝共聚物的主链是一种较为压缩的线团构象. 这种接枝共聚物高分子聚集体在新的纳米复合材料的合成方面有可能获得应用.     

Aggregation properties of oligo(methacrylic acid)-shelled dendrimer and its microenvironment in aqueous solutions

A third-generation poly(amido amine) dendrimer having poly(methacrylic acid) segments on the periphery (G3-PMAA) was newly synthesized. A xanthate-modified dendrimer (G3-X) was first prepared by condensation of the terminal amino groups of the poly(amido amine) dendrimer with an activated-ester xanthate. G3-PMAA was then synthesized by polymerization of methacrylic acid initiated with G3-X. The number-average degree of polymerization of PMAA segment was estimated to be 10. The pK_a value for G3-PMAA was evaluated to be 7.3 that is somewhat higher than that (6.8) of the corresponding linear PMAA with the same segment length, indicating the interaction of PMAA segments caused by assembling them at the dendrimer surface. When the diameter of G3-PMAA in aqueous solution at various pHs was measured by a dynamic light scattering, G3-PMAA was found to self-aggregate in a pH region, where the PMAA segment took a hydrophobic, compact coil conformation. Subsequently, the interaction of a fluorescent probe (1-anilino-8-naphthalenesulfonic acid ammonium salt (ANS)) with G3-PMAA was examined by means of fluorescence spectroscopy. As a result, ANS was found to bind to the hydrophobic site of G3-PMAA aggregates at lower pH, and to be released into water phase at higher pH.     

P(DEAM-co-MAA)在稀水溶液中构象行为的荧光探针研究

利用UV透光率测定,荧光探针技术等研究了N,N-二乙基丙烯酰胺(DEAM)与甲基丙烯酸(MAA)的共聚物P(DEAM-co-MAA) 在稀水溶液中的构象行为.结果表明，当共聚物中DEAM含量小于8.00％(molar fraction),溶液的pH < 6时,P(DEAM-co-MAA)在稀水溶液中的构象行为与聚甲基丙烯酸(PMAA)相似,共聚物可形成疏水微区,表现为一种较为高度压缩的线团构象;当共聚物中DEAM含量大于8.00％(molar fraction)时,由于高分子的稀释效应,P(DEAM-co-MAA)在pH 2～10范围内表现为较为松散的伸展构象.P(DEAM-co-MAA)构象随其组成和pH变化的这种性质有可能在新型敏感性凝胶的合成设计上获得应用.     

Interpolyelectrolyte reactions in solutions of polycarboxybetaines, 2: influence of alkyl spacer in the betaine moieties on complexing with polyanions

Series of polycarboxybetaines (PCB-n) of pyridiniocarboxylate structure with the same degree of polymerization but differing in the number, n, of methylene groups in the alkyl spacer between charges in the betaine moieties, n = 1, 2, 3, 4, 5, and 8, were synthesized. The utility of PCB-n as positively charged components of polyelectrolyte complexes was elucidated by potentiometry, turbidimetry, and fluorescence spectroscopy. Affinity of PCB-n to the pyrenyl-tagged poly(methacrylic) acid (PMAA) or DNA was judged from the stability of the corresponding polyelectrolyte complexes in water-salt solutions at different pH values as monitored by fluorescence quenching techniques. At pH = 9.0, PCB-1 formed the least stable complexes due to strong interaction of charged groups positioned in close proximity in the betaine moieties. The increase in n resulted in the irregular change of the affinity. Thus, as expected, PCB-2 formed noticeably more stable complexes than PCB-1. However, PCB-3 and, in particular, PCB-4 revealed weaker affinity to PMAA or DNA that is attributed to formation of stable ion pairs between charges in the betaine rings. At neutral and slightly acidic pH values binding of all PCB-n except PCB-1 was drastically enhanced due to protonation of PCB-n carboxylic groups that occurred with a DeltapH shift of 2-3 units to higher values as compared with the protonation of free PCB-n. The ability of added polyanion to compete with the betaine carboxylic groups in binding with the pyridinium groups was supported by potentiometric titration of PCB-n mixtures with sodium poly(styrenesulfonate): for n > or = 2, the binding of the polyanion-competitor also shifted protonation of carboxylic groups to higher values with DeltapH of more than 2 units. Practical ramifications of the revealed role of the alkyl spacer in polyelectrolyte complexation as well as the pH-induced stabilization of the complexes that occurs under enzyme-friendly conditions might extend to areas of biotechnology, specifically in bioseparation and gene delivery.     

Effect of cyclodextrins on pH-induced conformational transition of poly(methacrylic acid)

A pH-induced conformational transition of atactic poly(2-methylprop-2-enoic acid) (poly(methacrylic acid), PMMA) from the contracted to expanded conformation was investigated by viscometry, potentiometric titration, and anthracene solubilisation in the presence of low-molecular-mass non-ionogenic co-solutes-glucose, α-cyclodextrin (αCD), and γ-cyclodextrin (γCD), respectively. No effect of glucose and αCD on the conformational transition was observed with either of the methods used. On the other hand, the characteristic features of the conformational transition were absent in the presence of γCD. The different effects of the co-solutes indicate that the interaction between PMAA and γCD corresponds to the partial inclusion of the PMAA chain into the γCD cavity. The viscometry and anthracene solubilisation imply that γCD promotes the expanded conformation of PMAA at low pH. The potentiometric titration does not support this conclusion. Even though there is no break on the Henderson-Hasselbalch plot, a characteristic of the conformational transition, the potentiometric behaviour corresponds to that of the contracted PMMA conformation. Thus the results suggest the hierarchical picture of the PMAA conformation at low pH in which the local arrangement of the PMAA chain is a prerequisite for clustering on a larger scale.