EAA增容LLDPE/PEO共混物及其增容机理

以乙烯-丙烯酸共聚物(EAA)为增容剂,研究了它在线性低密度聚乙烯(LLDPE)/聚环氧乙烷(PEO)共混物中的增容作用及其增容机理.采用电子显微镜(SEM)、动态力学分析(DMA)、DSC和红外光谱(IR)对共混物形态及其微观结构进行了表征结果表明,EAA对LLDPE/PEO共混物有一定的增容作用;其增容机理为:EAA和LLDPE两者的非晶区部分相容,而EAA分子中的羧基与PEO分子中的醚氧基相互作用形成了分子间氢键.

Thermal, mechanical and ionic conductive behaviour of gamma-radiation induced PEO/PVDF(SIN)-LiClO4 polymer electrolyte system

An effort has been made to modify the mechanical behaviour of our previously reported gel-type gamma-radiation crosslinked polyethylene oxide (PEO)-LiClO4 polymer electrolyte. A highly polar and gamma-radiation crosslinkable crystalline polymer, polyvinylidene fluoride (PVDF), was selected to blend with PEO and then subjected to gamma-irradiation in order to make an simultaneous interpenetrating network (SIN), which was used as a polymer host to impart stiffness to the plasticized system. Experimental results have shown that the presence of PVDF in the system, through gamma-radiation induced SIN formation, could not only give a rather high mechanical modulus of 10(7) Pa at ambient temperature, but also maintain the room temperature ionic conductivity at a high level (greater than 10(-4) S/cm). DSC, DMA and conductivity measurement techniques were used to examine the effects of blending, gamma-irradiation and plasticization on the variations of glass transition and melting endotherm, on the appearance of high elastic plateau and on the temperature dependence of ionic conductivity: In addition, it was found that, in contrast with the unplasticized system, the ionic conductivity mechanism of this gel-type electrolyte seems to conform to the Arrhenius model, suggesting that, as a result of the high degree of plasticization, the polymer chains act mainly as the skeleton of the networks or polymer cages to immobilize the liquid electrolyte solution, whereas the ionic species migrate as if they were in a liquid medium. (C) 1997 Elsevier Science Ltd.

GAMMA-RADIATION INDUCED CROSS-LINKED PEO-LICLO4 SOLID-ELECTROLYTE SYSTEM

Aimed at raising the room temperature ionic conductivity of PEO-based solid polymer electrolyte and considered that the ionic conduction preferentially occurs in the amorphous phase, we lightly crosslinked the high MW PEO through gamma-irradiation and further suppressed the residual crystallinity by plasticizing with propylene carbonate. By incorporating LiClO4 salt to the above described polymer host, the ambient (25 degrees C) ionic conductivity of the electrolyte system could reach as high as 6.8 X 10(-4) S/cm. As the electrolyte was a crosslinked system, it was mechanically self-supportable. Based on the preliminary results of the electrochemical performance of the secondary lithium battery, assembled by using this kind of solid electrolyte and polyaniline as positive electrode, it is realized that the electrolyte thus prepared is of high expectancy.

PEO／EVA共混物的结构研究

ＰＥＯ以分散相形式存在于ＰＥＯ／ＥＶＡ共混物中，且具有部分相容性。Ｘ－射线衍射谱表明ＥＶＡ含有较强的ＰＥ衍射峰；ＰＥＯ／ＥＶＡ共混物既表现出ＰＥ的衍射峰也含有ＰＥＯ的晶面反射。随着ＰＥＯ的Ｍｎ的增加，ＰＥＯ／ＥＶＡ的Ｗｃ、ｘ增大且于时获得最大值：ＰＥ０／ＥＶＡ的Ｗｃ、ｘ值比纯ＰＥＯ的Ｗｃ、ｘ明显降低。

SYNTHESIS AND CRYSTALLIZATION BEHAVIOR OF (PP-MA)-G-PEO

A new graft copolymer (PP-MA)-g-PEO was synthesized by means of the chemical reaction between maleated polypropylene (PP-MA) and mono hydroxyl poly(ethylene oxide) (PEO-OH). The effect of reaction conditions on the degree of grafting of PEO-OH was studied

SOLID-STATE VOLTAMMETRY OF ELECTROACTIVE SOLUTES IN POLYMER SOLVENTS (PEO) AT ULTRAMICROELECTRODES

This paper describes the electrochemical oxidation and reduction of electroactive solutes which are dissolved in and diffusing through the polymer electrolyte solvent, poly(ethylene oxide) (PEO). The characteristics of electrochemical reactions in polymeric solutions are discussed, including how rigid solvent environments affect mass transport rates, and the transport phenomenon of electroactive species in PEO with bathing gases is explained by using the voltammetric theory of ultramicroelectrodes. The possibility that the microelectrode coated with PEO film can be used as a gas sensor has been discussed.

聚氧化乙烯(PEO)/聚双酚A羟基醚(PBHE)共混体系的非等温结晶动力学

本文联系Avrami方程和Ozawa方程,得出一个适合于非等温结晶动力学过程的新的基本方程,由这个方程可获得描述非等温结晶动力学过程的某些参数,并用DSC方法,对PEO/PBHE共混体系的非等温结晶动力学进行了研究,对实验结果进行了讨论.

PEO/PVP共混体系结晶行为

本文用WAXD、PLM、DSC方法研究了聚氧化乙烯(PEO)/聚乙烯基吡咯烷酮(PVP)共混体系的结晶行为,探索了两组分聚合物间相互作用及体系结晶度与非晶组分含量的关系。DSC研究表明PEO/PVP共混体系具有两个玻璃化转变温度,分别是纯组分的T_g,无相容性。应用Avrami和LH方程对其动力学参数进行了研究。偏光显微镜观察了共混物结构形态。

微量PEO-PS-PEO/PEO共混体系结晶过程中共聚物胶束的成核作用

本工作将Leibler等近期关于含非晶两嵌段共聚物“稀固体溶液”的胶束理论推广并应用到含结晶三嵌段共聚物的“稀固体溶液”.对微量聚氧化乙烯-聚苯乙烯-聚氧化乙烯三嵌段共聚物/聚氧化乙烯均聚物共混体系的结晶行为进行了研究.结果表明,共聚物胶束在共混体系的结晶过程中可以起到成核剂的作用.这对改善结晶均聚物的性能具有一定的应用价值.

THE IMPEDANCE STUDY OF MODIFIED PEO POLYMER ELECTROLYTE

The ultra-thin modified PEO (polyethylene oxide)-LiClO4 polymer electrolyte film (50-mu-m) was obtained by solution-casting technique. Impedance spectra were taken on the cells consisting of above PEO film electrolyte and ion-blocking or nonblocking electrodes. The ambient conductivity as high as 1.33 X 10(-4)S cm-1 could be achieved for PEO electrolyte modified by the crosslinking. It was shown that the resistance at the interface between solid polymer electrolyte and lithium electrode is growing with increasing the storage time. At high temperature, as 96-degrees-C, the ionic transport is clearly controlled by diffusion.

WATER-SOLUBLE AND AMPHIPHILIC POLYMERS .6. A STUDY ON THE SURFACE-COMPOSITION OF CAST FILMS OF PST/PMAA AND PEO-PST-PEO BLOCK POLYMERS BY XPS

Thin films of PSt/PMAA and PEO-PSt-PEO block polymers were deposited on a polystyrene substrate by solution adsorption (with or without solvent treatment), and the film surfaces were characterized by means of XPS. Direct solvent - casting of PEO-PSt-PEO from benzene solutions resulted in PSt-rich surfaces, whereas PMAA richer surfaces were obtained for PSt/PMAA films cast from DMF solutions. Moreover, solvent treatment after casting had profound effect on the film surface composition. Treatment with water markedly increased the surface concentration of polar PEO segments. In the case of PSt-PMAA block polymers, the PSt content on the surface increased in the order of water < ethanol < cyclohexane < petroleum ether, the last-named giving films with almost pure PSt surface. It is well worth noticing that the bulk composition had little to do with the surface composition for both PSt/PMAA and PEO-PSt-PEO block polymers within the composition range investigated when subsequent solvent treatment was applied.

PMMA-PEO共混体系的辐射交联

聚甲基丙烯酸甲酯(PMMA)是典型的辐射裂解型聚合物。经辐照后,PMMA主链发生无规断裂。在聚合物共混体系中,PMMA是否能发生交联,这是辐射化学中一个非常重要的研究课题之一,也是一项探索性工作。 PMMA-PEO共混体系是可以分子水平共溶的体系。本文试图将共混体系的相容性与共混体系中的裂解型聚合物的辐射效应联系起来,讨论PMMA-PEO共混体系的辐射交联。

PEO/PBHE共混体系X射线散射研究

在聚环氧乙烷(PEO)/聚双酚A羟基醚(PBHE)共混体系中PEO是一个强质子受体,而PBHE是一个强质子给体,两者极易形成氢键,十分有利于形成互容对。笔者研究了PEO/PBHE共混体系的相容性,等温及非等温结晶动力学,本文根据Vonk提出的一维电子密度相关函数,分析了PEO/PBHE的SAXS现象,求得了共混体系的结晶度,片晶层厚度,过渡层厚度及长周期等结构参数。

PEO/PVAc共混体系辐射交联反应中溶胶分数与辐照剂量间的关系

交联度对由聚合物共混物辐射交联而制备出的材料的性能影响很大,研究共混体系的辐射交联度和交联行为是十分重要的。通常,用溶胶分数与辐照剂量间的关系表征聚合物的交联度和交联行为。文献[2]发现线性聚合物的溶胶分数与辐照剂量间的关系与高分子链结构参数有关。本文试图考察共混体系的辐射交联行为是否也与高分子链结构有关,并将线性聚合物的关系式(1)推广应用到PEO/PVAc共混体系中。目前,有关这方面的研究工作还未曾见文献详细报道。

交联共聚物(ER-PEO)及其与NaSCN络合物的结构研究

环氧树脂(ER)与聚环氧乙烷(PEO)的共混物经水/乙醇萃取后的剩余物为交联ER-PEO非晶共聚物。萃取分析表明,ER/PEO中约有50wt·％的PEO与ER形成ER-PEO交联共聚物。ER/PEO与NaSCN络合后,由于Na~+的配位络合作用,使结晶能力进一步降低。