高分子共混体系界面张力的研究

METHOD OF ESTIMATING INTERFACIAL TENSION IN POLYMER SYSTEMS

在高分子多相体系中,相间界面张力(γ_(12))是微区的重要控制因素,无论是Donatelli,Sperling等提出的IPN体系微区尺寸关系式,还是Tokita提出的共混体系中分散相粒径表达式,都含有界面张力因子。 然而,由于高分子体系中界面张力测定的诸多实际困难,当前在国内外非常多的研究工作中,广泛地采用了一些替代的办法,应用较多的有以表面张力差来代替界面张力的Antonow原则延伸及一些近似的计算方法。

It is demonstrated that surface tension difference (AY) can neither act as interfacial tension (γ12) nor as a substituent of γ12 in polymer studies. At present, AY is still being wrongly used as substituent of γ12 in polymer investigation, because γ12 in polymer system is very difficult to measure. With a purpose to solve the problem, an estimating method of γ12 from the value of breaking energy based on the domain prediction theory of polymer blends developed by the authors is proposed as:γ12=E/3B where B is the experimental constant in domain prediction theory; E is macroscopic bulk breaking energy of particle in polymer blends. Using this method, γ12 of any polymer system can be obtained so long as E and B are known. In the case of EPDM, the value of E at 195℃ was found to be 3. 3×102 J/M3.Besides, two equations based on the modification of Wu's equation and Girifalco's & Wu's equation are proposed to fit some special cases as:When the polarity of both polymer materials is very strong or very weak. When the structure and composition of two polymer materials are almost same. Where γ1 is surface tension of polymer 1 at temperature 1 (T1)γ1' is surface tension of polymer 1 at temperature 2 (T2)γ2 is surface tension of polymer 2 at T1γ2' is surface tension of polymer 2 at T2