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1.
改变聚(甲基丙烯酸甲酯-苯乙烯(P(MMA-co-St)中 甲基丙烯酸甲酯的含量(WMMA),通过一步法合成出聚环氧氯丙烷聚氨酯(PU(PECH)/P(MMA-co-St)IPN.DSC、TEM和动态粘弹谱研究结果表明:当P(MMA_co-St)中WMMA大于0.6时,IBN仅有一个Tg;当WMMA小于0.4时,IPN有2个Tg,TEM上出现相区,P(MMA-co-St)深度参数(δ)及δ的氢键作  相似文献   

2.
改变聚(甲基丙烯酸甲酯-苯乙烯)(P(MMA-co-St)中甲基丙烯酸甲酯的含量(W_(MMA)),通过一步法合成出聚环氧氯丙烷聚氨酯(PU(PECH)/P(MMA-co-St)IPN.DSC、TEM和动态粘弹谱研究结果表明:当P(MMA-co-St)中W_(MMA)大于0.6时,IPN仅有一个Tg;当W_(MMA)小于0.4时,IPN有2个T_g,TEM上出现相区,P(MMA-co-St)溶度参数(δ)及δ的氢键作用分量(δh)与相态、力学性能有密切关系。  相似文献   

3.
聚环氧乙烷为支链的两亲共聚物的表征及性能   总被引:5,自引:0,他引:5  
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.  相似文献   

4.
THEREACTIONOF(μ_3-CPh)Co_3(CO)_9WITH TRANSITIONMETALCARBONYLANIONM(CO)_3(RCOCp)ANDCHARACTERIZATIONOFCLUSTERS(μ_3-CPh)CO_2M(CO)_8(RCOCPp)(M=Mo,W;R=H,CH_3.C_2H_5O)Authortowhomcormspondenceshouldaddressed.ExperimentalsectionGeneralprocedureandmaterialAlloperationwascarriedoutunderhighlypurenitrogenatmosphereusingshadardSchlenlcandvacuumtechniques.He-cane,benzeneandtetrahydrofuranwerepredriedoversodiumwireanddistilledfromsodium-benzophenoneundernitrogen.NaM(CO)3(RCOCP)andPhCCo3(CO),werepreparedaccordingtoliteratUre  相似文献   

5.
研究了几种新型含有机硅二元和三元多嵌段共聚物的氧,氮选择透过性能。其中双酚A聚羟基醚-聚二甲基硅氧烷二元多嵌段共聚物-(PHE-PDMS)的透氧系数P02=510Barrer,氧氮分离系数a02/N2=2.2;聚苯醚-聚二甲基硅氧烷-聚对羟基苯乙烯三元多嵌段共聚物-(PPO-PDMS-PHS)的P02=156Barrer,do2/N2=2.4,两者都具有良好的力学性能,此外,含有机硅三元多嵌段共聚  相似文献   

6.
用二苯甲烷钾为引发剂,阴离子聚合法合成了苯乙烯(St)-环氧乙烷(EO)嵌段共聚物,并用FTIR,^1H-NMR,SEC,WAXD和动态粘弹谱对共聚物进行了表征。结果表明所得聚合物为分子量可控,窄分布的两嵌段共聚物。  相似文献   

7.
可生物降解的聚乳酸弹性体的合成与表征   总被引:4,自引:0,他引:4  
本文将丙交酯(DL-LA)与聚乙二醇(PEG)的预聚体用甲苯-二异氰酸酯80(TDI)扩链,得到了一系列的聚乳酸(聚醚)型聚氨酯(PEG-PLA/PU)弹性体。对预聚体和弹性体分别进行了IR、HNMR和DMA表征,并测定了弹性体的力学性能。结果表明,LA与PEG生成的预聚体是一种三嵌段结构:HO-PLA-PEG-PLA-OH。随着PEG含量的增加,弹性体的玻璃化温度下降;PEG分子量增大时,弹性体  相似文献   

8.
ANOVELAPPROACHFORTHEPREPARATIONOFMEDIUM-SIZELACTAMS¥YunXinBo;DongLuBAI(ShanghaiInstituteofMateriaMedica,ChineseAcademyofScien...  相似文献   

9.
IN-SITU FTIR AND UV-VISIBLE-NEAR-IR SPECTROELECTROOHEMICAL STUDIES OF MIXED-VALENCE ISOPOLYANION Mo_6O_(19) ̄(3-) IN APROTIC M...  相似文献   

10.
ASTUDYONTHEKINETICSOFEXCHANGEREACTIONSOFW(Ⅵ)ORMo(Ⅵ)WITHINMACROPOROUSANIONEXCHANGERESIN(D290)PHASEWangYukun(DepartmentofChemic...  相似文献   

11.
利用原子转移自由基聚合反应合成了以聚苯乙烯-b-聚(乙烯-co-丙烯)(SEP)为主链、无规分布且数目可控的聚甲基丙烯酸乙酯(PEMA)为支链的嵌段接枝共聚物SEPG.发现在甲苯中因支链PEMA与聚(苯乙烯-co-对六氟羟丙基-α-甲基苯乙烯)[简称PS(OH]的氢键络合作用和EP嵌段的溶解作用导致了聚集体的胶束化.研究了胶束的尺寸及其分布对PS(OH)中羟基含量和共混物组成的依赖性.  相似文献   

12.
In this paper, we briefly report the main results of our work on the effect of introducing specific interaction on the miscibility of otherwise immiscible polymer blends. A strong proton-donating unit (CF3)2(OH)C- was incorporated into polystyrene (PS(OH)). A series of blends of PS(OH) with one of polyacrylates such as PBA, PMMA, PEMA and PBMA was studied. The infrared spectra of the blends present convincing evidence of the formation of hydrogen bonding. The frequency shift of the OH stretching band due to H-bonding is independent of the structure and composition of the hydroxyl-containing polymers, but clearly dependent on those of the counterpolymers. Both excimer and nonradiative energy transfer (NRET) fluorescence techniques have proved effective for monitoring the variation of the degree of molecular interpenetration with the density and strength of the hydrogen bonds in the blends. TEM observations reveal clear and regular variation in the morphology of the blends with the content of hydroxyl-containing groups. The morphological features of this kind of blends are almost controllable since the structure and/or amount of the introduced groups forming hydrogen bonding are readily adjusted in chemistry. NRET and viscosity measurements of solutions of polyacrylate and PS(OH) with relatively high hydroxyl contents in toluene provide evidence of the intermolecular complexation. In addition, the effect of introducing simultaneously crosslinking and intermolecular hydrogen bonding into blends of PS and PBA on miscibility was studied. It is concluded that single phase IPN can be prepared, but much higher content of the proton donor is needed in comparison with the blends of the corresponding linear polymers. The interlocking structure of the networks appears unfavourable to forming miscible IPN.  相似文献   

13.
The vibrational characteristics (vibrational frequencies, infrared intensities and Raman activities) for the hydrogen-bonded system of Vitamin C (L-ascorbic acid) with five water molecules have been predicted using ab initio SCF/6-31G(d,p) calculations and DFT (BLYP) calculations with 6-31G(d,p) and 6-31++G(d,p) basis sets. The changes in the vibrational characteristics from free monomers to a complex have been calculated. The ab initio and BLYP calculations show that the complexation between Vitamin C and five water molecules leads to large red shifts of the stretching vibrations for the monomer bonds involved in the hydrogen bonding and very strong increase in their IR intensity. The predicted frequency shifts for the stretching vibrations from Vitamin C taking part in the hydrogen bonding are up to -508 cm(-1). The magnitude of the wavenumber shifts is indicative of relatively strong OH...H hydrogen-bonded interactions. In the same time the IR intensity and Raman activity of these vibrations increase upon complexation. The IR intensity increases dramatically (up to 12 times) and Raman activity increases up to three times. The ab initio and BLYP calculations show, that the symmetric OH vibrations of water molecules are more sensitive to the complexation. The hydrogen bonding leads to very large red shifts of these vibrations and very strong increase in their IR intensity. The asymmetric OH stretching vibrations of water, free from hydrogen bonding are less sensitive to the complexation than the hydrogen-bonded symmetric OH stretching vibrations. The increases of the IR intensities for these vibrations are lower and red shifts are negligible.  相似文献   

14.
2-(5-Methyl-1H-benzimidazol-2-yl)-4-bromo/nitro-phenols (HLBr and HLNO2) and their Zn(II) complexes with ZnX2 (X = Cl, I, NO3) were synthesized and characterized by elemental analysis, molar conductivity, IR, 1H and 13C NMR spectra. The OH proton appears near the NH protons in the 1H NMR spectra of the ligands because of the strong intramolecular hydrogen bonding between the OH hydrogen and the C=N nitrogen atoms. The complexation is investigated in ethanol and isopropanol and it is observed that isopropanol is a better solvent than ethanol for the complex forming. HLBr gives harder complexation reaction with Zn(II) according to HLNO2 because of the stronger intramolecular hydrogen bonding in HLBr, and the both ligands react easier with Zn(NO3)2 than ZnCl2 and ZnI2. The Zn(II) complexes of HLBr have 1:1 M:L ratio and ionic character, however, HLNO2 give a non-ionic complex that has 1:2 M:L ratio. In the complexes the phenolic hydrogen is eliminated and a chelate structure is formed.  相似文献   

15.
Polymer complexes were prepared from high molecular weight poly(acrylic acid) (PAA) and poly(styrene)‐block‐poly(4‐vinyl pyridine) (PS‐b‐P4VP) in dimethyl formamide (DMF). The hydrogen bonding interactions, phase behavior, and morphology of the complexes were investigated using Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), dynamic light scattering (DLS), atomic force microscopy (AFM), and transmission electron microscopy (TEM). In this A‐b‐B/C type block copolymer/homopolymer system, P4VP block of the block copolymer has strong intermolecular interaction with PAA which led to the formation of nanostructured micelles at various PAA concentrations. The pure PS‐b‐P4VP block copolymer showed a cylindrical rodlike morphology. Spherical micelles were observed in the complexes and the size of the micelles increased with increasing PAA concentration. The micelles are composed of hydrogen‐bonded PAA/P4VP core and non‐bonded PS corona. Finally, a model was proposed to explain the microphase morphology of complex based on the experimental results obtained. The selective swelling of the PS‐b‐P4VP block copolymer by PAA resulted in the formation of different micelles. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1192–1202, 2009  相似文献   

16.
用稳态和震荡剪切实验研究了水杨酸钠(NaSal)对50 mmol·L-1阳离子Gemini表面活性剂2-羟基-(三亚甲基-α,ω-双十二烷基三甲基溴化铵和三亚甲基-α,ω-双十二烷基三甲基溴化铵, 简写为12-3(OH)-12和12-3-12)水溶液中形成蠕虫状胶束及其性质的影响. 在无盐状态下, 50 mmol·L-1的12-3(OH)-12或12-3-12在水溶液中仅形成球状或棒状胶束. NaSal可促进上述两体系胶束的生长, 生成蠕虫状胶束. 比较而言, 12- 3(OH)-12对NaSal更敏感, 可以在低盐浓度下生成蠕虫状胶束. 而且与12-3-12体系相比, 12-3(OH)-12生成了更长的蠕虫状胶束. 这些差别在于12-3(OH)-12体系中存在羟基连接链之间的氢键作用, 这增加了12- 3(OH)-12头基的亲水性, 促进了反离子的解离, 增大的胶束表面电荷密度更强烈地结合水杨酸根反离子, 减小了头基间的静电斥力, 反过来又增强了分子间氢键, 致使 12-3(OH)-12胶束迅速生长.  相似文献   

17.
To investigate the effects of solvent type and temperature on the interpolymer complexation via hydrogen bonding, a study was made on the complex system of poly(acrylic acid) (PAA) and poly(ethylene oxide) (PEO) in two kinds of solvent systems, pure water and water-MeOH (30 wt%) mixed solvent, at various temperatures using the Ubbelohde viscometer, pH-meter, and UV spectrophotometer. The repeating unit mole ratio at the most optimum complexation as confirmed by the reduced viscosity measurement was shifted from [PEO]/[PAA] ≈ 1.25:1 to 1.5:1 by the addition of methanol to water. From the UV measurement, the deviation from the “isosbestic point” (where the absorbance of the solution remains constant) has presented another evidence for the solvent effect on complexation. In addition, the analysis of the changes in thermodynamic properties upon complexation as well as the fraction of carboxyls associated with PEO oxygens and the complex stability constant as estimated by potentiometric titration at several temperatures reveals that the complex formation in mixed solvent became more unfavorable compared to that in pure solvent at high temperatures above 30°C. This could be explained by considering that in water the hydrophobic interaction as well as the hydrogen bonding may greatly contribute to the stabilization of the polymer complex formed, while in water-methanol the main stabilizing force would be the hydrogen bonding alone.  相似文献   

18.
Poly(styrene)-block-poly(4-vinylpyridine) (PS-b-P4VP) copolymers and poly(acrylic acid) (PAA) have been mixed in organic solvents. Complexation via hydrogen bonding occurs between the P4VP and PAA blocks. Those insoluble complexes aggregate to form the core of micelles surrounded by a corona of PS chains. Reorganization of these structures occurs upon addition of acidic or basic water, which results in the breaking of the hydrogen bonds between the P4VP and PAA blocks. After transfer of the initial complexes in acidic water, micelles consisting of a PS core and a protonated P4VP corona are observed. In basic water, well-defined nanoparticles formed by the PS-b-P4VP copolymers are obtained. It is demonstrated that these nanoparticles are stabilized by the negatively charged PAA chains. Finally, thermally induced disintegration of the micelles is investigated in organic solvents.  相似文献   

19.
Based on our long-term research on interpolymer complexation due to hydrogen bonding, we proposed several novel self-assembly approaches to polymeric micelles with regular structures. Differing from micelles of block and graft copolymers, our micelles don't have any chemical bonds between the core and shell. In addition, some of these approaches have been proved to be effective to fabricate hollow aggregates.  相似文献   

20.
Amphiphilic diblock copolymers of polystyrene (PS) and poly(N‐vinylpyrrolidone) (PNVP) were prepared by a combination of ATRP and MADIX. Well‐defined PS with bromine end group was synthesized by ATRP in bulk at 110 °C using (1‐bromoethyl) benzene as an initiator. The Br‐ end group was then converted to xanthate as verified by 1H NMR spectroscopy, elemental analysis, and UV‐spectroscopy. PS‐b‐PNVP copolymers were produced by MADIX of NVP in bulk at 60 °C using PS‐xanthate as a macro‐chain transfer agent and the kinetics of polymerization were investigated. The structures of PS‐b‐PNVP were characterized using GPC and 1H NMR. Amphiphilic PS‐b‐PNVP could form spherical micelles with PS cores and PNVP shells in aqueous solution as confirmed by 1H NMR and laser light scattering (LLS). The values of critical micelle concentration of PS‐b‐PNVP and the average aggregation number of PS‐b‐PNVP in the micelles were measured using pyrene as a probe and static LLS, respectively. The aggregation number increases concomitantly with temperature (10–50 °C), but the hydrodynamic radius of the micelles remains almost constant over the same temperature range, which may indicate shell dehydration at a higher temperature. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5604–5615, 2008  相似文献   

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