The Effect Of Adding Glass Beads On Phase-separation Of PMMA/SAN Blends

Through the dynamic rheological measurements, small angle laser light scattering (SALLS) and transmission electrical microscope (TEM), we have studied the effects of addition of hollow glass beads (HGB) on phase-separation for poly(methyl methacrylate) / poly(styrene -co-acrylonitrile) (PMMA/SAN) blends with a LCST-type behavior.On the basis of that HGB have hardly influence on the linear viscoelasticity theory in low frequencies (co) region for homogeneous polymer system, the effects of filled HGB on the miscibility and phase-separation of PMMA/SAN blends were characterized by the dynamic viscoelastic functions such as storage modulus (G') and the loss tangent (tan δ) versus co, respectively. It is found that at above phase-separation temperature (Ts), the "secondary plateau" appearing in the terminal region, which is attributed to the phase-separation of PMMA/SAN blends. The results demonstrated that the addition of HGB has an "induced effect" on the phase-separation of polymer blends, which embodies that adding HGB made the "secondary plateau" of co in the terminal region of storage modulus (G') versus co plot moved higher, and it becomes more obvious flattening for filled polymer blends at the same conditions. However, it is suggested that this kind of "induced effect" is related to the HGB content and size. The higher the particles content added, and the smaller the particles size, the larger interfacial areas are, leading to the stronger interaction between the particles and polymer matrix.It is found that for the PMMA/SAN blends with different component, the effects of adding HGB on the phase-separation for polymer blends are also different due to the difference of the interactions between particles and PMMA or SAN matrix. The phase-separation temperature (Ts) of PMMA/SAN (20/80) blend filled with HGB is obviously lower than that of unfilled system. It is also found that the addition of GB also has an influence more or less on the morphology and domain size of polymer matrix. However, the addition of HGB have no influence on the phase-separation mechanism of PMMA/SAN blends followed the spinodal decomposition (SD) mechanism.