聚氧乙烯-镧系金属盐(Ln3+)的络合对聚氧乙烯形态结构的影响

采用偏光显微镜(POM)、差示扫描量热(DSC)和X 射线衍射,对聚氧乙烯(PEO)的形态结构和热物理行为随6种镧系盐对PEO的摩尔比变化的规律进行了系统的探讨.结果表明,随六合水氯化镧系盐摩尔比的增加,PEO球晶行为、熔点和熔融热均逐渐减弱,当盐对PEO的摩尔比达到一定值时(如YbCl3·6H2 O :PEO =2 0 ) ,则PEO完全不结晶.不同的镧系盐对PEO结晶的影响程度不同.X 射线衍射分析的结果也表明PEO晶面衍射峰随Ln3+ 盐摩尔比的增加而下降,与POM和DSC结果一致的.结果还表明较高的干燥温度(6 0℃)对PEO与Ln3+ 的相互作用有促进作用.对比二次降温的试样与原始试样的结晶行为,降温后结晶试样的特征表明络合在降温结晶后还存在.红外结果表明PEO与Ln3+ 的相互作用是络合作用.

THE INFLUENCE OF COMPLEX OF PEO-LANTHANIDE(Ln3+) SALTS ON THE MORPHOLOGY OF PEO

The morphological structures and the related thermophysical properties of the co mplex differential of polyethylene oxide and lanthanide salts (Ln 3+) were investigated by polarized optical microscope (POM) and differential sca nning calorimeter (DSC).The results showed that with the increase of molar rati o of Ln 3+ salts to PEO,PEO spherulites were gradually demolished.When the molar ratio reached a critical value,for example,20,PEO spherulites compl etely disappeared.Different Ln 3+ salts have different ef fect on PEO spherulites.The results of X-ray diffraction indicated the decrease of main peaks at 2θ=19.2° and 23.4° with the increase of Eu 3+salt co ncentration,whi ch coincided with the data of DSC and POM.The characteristic of spherulites of c ompl ex samples was much weaker after vacuum drying at 60℃ than that at 23℃ in fume hood.Comparing the spherical structure of the original cast-drying sample,we f oun d that the complex between PEO and Eu 3+ remaimed after the first cooling. The melting point and heat of fusion of PEO decrease with the increase of Ln 3+ concentration.When the concentration reached the related critical valu es,melting endoth erms disappeared and melting points of PEO were down to the lowest values.The ch an ge of FT-IR band at 1036 cm -1 confirmed the complex characteristic of th e interaction between PEO and Ln 3+ salts.