Phase Formation And Evolution Of Multiphase Polymer Blends

In this paper, the phase formation, morphology and evolution was studied,besides the mechanism of the phase evolution. The characteristic length anddiameter was defined to describe the dynamic evolution rule using scanningmicroscope graphs. The distribution of diameter of the dispersed phase is proved tocomply with the normal-log distribution based on the graph-estimation theory, and theparameter σ is was calculated to describe the distribution width of diameter.Besides, the uniformity of the distribution of sizes and the spatial distribution wasstudied using theory on fractal. The phase contrast graph was transformed to 2DFTimage according to theory on Fourier Transformation. Corresponding parameters wascomputed to describe the relation between the phase evolution and different mixingtimes, compositions, mixing temperatures, etc. According to Debye-Bueche theorysome parameters describing the phase structure, such as correlation distance ac,integral invariant Q, fractals dimension Df and so on, were calculated. The resultsshows that the changes mainly occurs in the initial stage of the mixing. In the latestage, the change levels off due to the dynamic equilibrium between the breakup andcoalescence of particles. There exists a optimal rotating speed at which the phasestructure is more exquisite. Moreover, sizes of particles increase as the volumefraction of the dispersed phase rises.Rheological and mechanical properties were also tested, and the resultsconfirmed the intimate relation between the mechanical properties and the structure.For PS/PP immiscible blends, the dispersed phase shows a role of disfigurement, so,the more exquisite the phase morphology is, the more unperfect the property is.However, the situation is different if compatibility is added. The results of rheologicaltest indicates the compatibility between PS and PP will be improved in the quiverfields.The mechanism of phase evolution was studied. The results shows that in theinitial stage of the mixing, the breakup of particles complies with a crisp-break rule.In this period, the phase evolution has a self-similarity and the structural function hasa scaling behaviour. But in the late stage of the mixing, such results is no longertenable. The quantificational relation between Youngs modulus and the possessingconditions based on the crisp-break rule is tenable in the earlier stage of the mixing.The theoretic value of modulus can be a prediction for the real one. But, in the latestage, because of the effect of the interface, this model loses the applicability.