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1.
聚氧化乙烯水溶液粘度的测定   总被引:3,自引:0,他引:3  
测定了不同分子量聚氧化乙烯(PEO)在水溶液中的粘度,发现在低浓度区高分子溶液比浓粘度出现负偏离。用高分子溶液流过时间对浓度作图的外推值t0^*重新计算相对粘度,则高分子溶液比浓粘度与浓度之间满足线性关系。不同分子量PEO水溶液流过时间对浓度作图的外推值t0^*是完全一致的。利用纯溶剂在粘度计中流过时间的改变确定了高分子在毛细管管壁上吸附层的厚度,发现PEO在毛细管管壁上吸附层厚度与分子量无关。  相似文献   

2.
粘度法研究高分子溶液行为的实验改进(Ⅱ)   总被引:13,自引:0,他引:13  
高分子在粘度计毛细管管壁上的吸附不仅会导致毛细管有效管径减小,而且可以导致毛细管界面性质发生显著改变,具体表现为测定高分子溶液流过时间t之前和之后纯溶剂的流过时间t0和t0′与高分子溶液流过时间t对浓度作图外推到浓度为零时的值t0^*并不一致。不同温度时聚乙烯吡咯烷酮(PVP)水溶液粘度测定结果表明,当吸附讷发子显著改变了毛细管界面性质时,需要将高分子溶液粘度测定方法由t/t0′改为t/t0^*。经过改进的粘度测定方法不仅更加普适合理,而且更加简单有效。  相似文献   

3.
极低浓度区高分子溶液异常粘度行为研究进展   总被引:2,自引:2,他引:2  
极低浓度区高分子溶液粘度的测定涉及到外推法确定高分子溶液特性粘数的实验基础。综述了极低浓度区高分子溶液反常粘度行为的起源,探讨了粘度计毛细管管壁上高分子吸附层、界面效应、高分子溶液或溶剂在毛细管中流动模式的改变、高分子与毛细管管壁界面间相互作用、乌氏粘度计结构限制等对极稀高分子溶液粘度的影响,以及正确测定极低浓度区高分子溶液粘度的实验方法。  相似文献   

4.
粘度法测定聚乙烯醇相对分子质量的实验改进   总被引:1,自引:0,他引:1  
对在25℃时测定聚乙烯醇(PVA)水溶液粘度的实验进行了改进,以高分子溶液流过时间对浓度作图的外推值t0*代替纯溶剂的流过时间t0计算PVA水溶液的相对粘度ηr,结果表明可以得到较好的实验结果。  相似文献   

5.
高分子在固体表面上的吸附层厚度对了解其结构具有重要意义.厚度的测量通常采用椭圆偏振法、流体力学法和沉降法等几种方法来测量[1].流体力学法始创于50年代中期Ohrn[2]对极稀高分子溶液粘度异常行为的解释.由于高分子在粘度计的毛细管管壁上的吸附,致使...  相似文献   

6.
应用自洽场理论(SCFT)研究了受限于球内的高分子溶液的结构,重点关注高分子链在受限壁附近的行为.根据自洽场理论数值计算结果,讨论了球半径、高分子与球限制壁的相互作用、高分子平均浓度等因素对球内高分子浓度分布的影响.从高分子浓度分布和吸附/排空层厚度可以发现,在一定的条件下,受限的高分子在受限壁上会发生吸附/排空转变.吸附/排空转变与受限球大小、高分子链长和平均浓度,以及高分子链与受限壁之间相互作用都有关系.理论预测发生吸附/排空转变时的高分子与球限制壁的临界相互作用参数与链长的倒数成线性关系,且斜率与球半径有关.限制球越小,要发生吸附/排空转变,需要高分子与球之间有更大的临界吸引能.  相似文献   

7.
本文从高分子溶液粘度和浓度依赖性中的斜率系数和高分子溶液流动时的流体力学及热力学因素之间关系着手,由9种高分子-溶剂体系的粘度数据,建立了一个新的一点法测定特性粘数方程。即: [η]=η_(sp)/c/(1+1/2(1-x)η_(sp)) 此式不仅是一个一点法测定特性粘数的新的方程,而且也是一个由高分子溶液粘度数据估计高分子-溶剂相互作用参数X的方程。  相似文献   

8.
高分子薄膜在化工制造、绿色能源、材料、光电以及生命科学等领域有着重要的应用.溶剂蒸发作为高分子薄膜加工制备的重要手段,因其操作简单、成本较低和易于大规模制备的优点而被广泛应用和研究.本文综述了利用蒸发效应调控高分子溶液沉积图案、制备功能性高分子薄膜的研究进展,包括蒸发诱导高分子沉积图案的实际应用、基本原理和技术手段三个方面.本文旨在梳理该领域的各个研究方向及其相互联系,通过阐述溶剂蒸发对高分子沉积图案影响的机理为后续研究提供思路.此外,本综述简要总结了高分子溶液蒸发领域未解决的问题,并对未来发展方向进行了展望.  相似文献   

9.
高分子稀溶液中偏离Huggins方程式的五种情况   总被引:1,自引:0,他引:1  
在对高分子溶液的粘度研究中发现,在稀溶液中会出现五种偏离Huggins方程式的情况。本文就这五种情况作了较为详细的介绍,尤其就高分子-高分子和高分子-溶剂分子间的相互作用对二元体系(溶剂-聚合物)和三元体系(溶剂-聚合物A-聚合物B)粘度的影响进行了深入的讨论。  相似文献   

10.
综述了具有剪切增稠性质的高分子溶液及其流变行为,分析了高分子溶液剪切增稠的机理,讨论了高分子浓度、分子量和高分子组成等对剪切增稠高分子溶液流变行为的影响,最后介绍了高分子剪切增稠体系在石油开采、抗冲减振及日用化工等领域的应用。  相似文献   

11.
12.
应用外部电容耦合式等离子体聚合装置.研究了苯硫酚等离子体聚合规律,找到了最佳聚合条件,通过热失重、红外光谱、X-射线衍射、电子衍射、GC-MS和接触角测定等研究了聚合物结构与性能。电导率测定表明等离子体聚苯硫酚具有半导体性质。  相似文献   

13.
用不同沉淀剂沉淀出来的聚甲基丙烯酸三苯基锡酯(PTPTM)具有不同的溶解性能。本文用FTIR研究了PTPTM中存在的各种不同的配位形式及其对PTPTM的凝聚态结构和溶解性能的影响。讨论了PTPTM可能存在的三种凝聚态以及在不同条件下的相互转化。  相似文献   

14.
天然-合成高分子生物杂化材料在生物医学领域中的应用   总被引:1,自引:0,他引:1  
综述了天然—合成高分子生物杂化材料在生物医学领域中的应用,并分析了它作为组织工程基质和药物载体的优点,指出生物杂化材料是生物医用材料的发展趋势。  相似文献   

15.
This study reports a continuous prepartion of spherical or hemispherical polymer particles simply utilizing the phase separation in polymer blend films during the coating process. We took an advantage of the strong phase separation between a water‐soluble crystalline polymer as a matrix and hydrophobic polymers as minor components. We demonstrated the prepartion of water‐soluble polystyrene (PS) particles, nitrilotriacetic acid (NTA)‐functionalized PS particles for protein separation, and semiconducting poly(3‐hexylthiophene) (P3HT) particles. The sizes of the particles could be controlled by adjusting the film thickness and weight fraction of the minor component polymers in the blend film. It provides a simple facile way to prepare polymer particles in a continous process.

  相似文献   


16.
Conducting polymer synthesis of a new benzobisoxazole/thiophene derivative is reported. The conjugated co-polymer presents the lowest bandgap (1.78 eV) reported for a neutral benzobisoxazole/thiophene polymer. Electrochemical polymerization is carried out by cyclic voltammetry, and the new conducting polymer is characterized by Raman spectroscopy and X-ray photoelectron spectroscopy. The results indicate that the coupling of the monomer unit occurs at the 2,2′ positions of the thiophene ring. Theoretical studies in derivatives of this family of compounds are conducted to validate the effect on the bandgap modulation due to the change in the substituent on the phenyl moiety of the monomer. The comparison between experimental and theoretical properties shows the substituents impact on the optical properties of the system, and its viability to be used in sensors.  相似文献   

17.
基于PEO的复合聚合物电解质的研究进展   总被引:2,自引:1,他引:2  
从填料对聚合物电解质性能的影响、复合聚合物电解质性能的影响因素、聚合物电解质的结构和复合聚合物电解质的应用四方面综述了基于聚氧化乙烯(PEO)的复合聚合物电解质研究的最新进展。聚合物中加入纳米级无机填料可提高聚合物电解质的机械强度、电导率和锂/电解质界面的稳定性。  相似文献   

18.
Biodegradable poly(butylene succinate) (PBSU)/carboxyl‐functionalized multi‐walled carbon nanotubes (f‐MWNTs) nanocomposites were prepared via solution casting method at low f‐MWNTs loadings of 0.5 and 1 wt%, respectively, in this work. Scanning and transmission electron microscopic observations reveal a fine dispersion of f‐MWNTs throughout the PBSU matrix. Non‐isothermal melt crystallization at different cooling rates, isothermal melt crystallization at different crystallization temperatures, spherulitic morphology, and crystal structure of neat PBSU and its nanocomposites were investigated with various techniques in detail. The addition of f‐MWNTs is found to enhance the crystallization of PBSU, apparently in the nanocomposites during both nonisothermal and isothermal melt crystallization, due to the heterogeneous nucleation effect; however, the crystallization mechanism and crystal structure of PBSU remain almost unchanged. Effect of the presence of f‐MWNTs and their loadings on the thermodynamic driving force for nucleation and nucleation activity of PBSU was evaluated quantitatively through two methods. Moreover, it is found that incorporating with 1 wt% f‐MWNTs significantly improves the storage modulus of PBSU in the nanocomposites by about 147% at room temperature as compared with that of neat PBSU. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

19.
Molecular simulations (Dissipative Particle Dynamics - DPD) were used to quantify the effect of polymer adsorption on the effective shear viscosity of a semi-dilute polymer solution in microchannel Poseuille flow. It is well known that polymer depletion layers develop adjacent to solid walls due to hydrodynamic forces, causing an apparent wall slip and reduced effective viscosity (increased total flow rate). We found that depletion layers also developed in the presence of hydrodynamically rough adsorbed layers on the wall. Polymer-polymer (steric) repulsion between flowing and adsorbed polymer expanded the depletion layer compared to no-adsorption cases, and the effective viscosity was reduced further. Desorption occurred for higher shear rates, reducing the repulsion effect and shrinking the depletion layers. A phenomenological algebraic model for the depletion layer thickness, including a shear modified adsorption isotherm, was developed based on the simulation data. The depletion layer model can be used together with the effective viscosity model we developed earlier.  相似文献   

20.
We successfully synthesized the first conjugated polymer containing a bismuth atom in the conjugated main chain by incorporating a bismuth atom into the cyclopentadiene framework (bismole), which was constructed by a polymer reaction. A synthetic procedure and characterization of the obtained polymers were discussed. This bismole‐containing conjugated polymer exhibited moderate bluish green photoluminescence in solution. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4857–4863, 2006  相似文献   

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