“PMMA/PC Blends: Effect of mixing conditions on compatibility”

In this work the effect of melt mixing condition and of a
transesterification catalyst on miscibility of poly(methyl methacrylate)
(PMMA)/polycarbonate of bisphenol A (PC) blends is studied. In particular, at high
temperature chemical reactions between PMMA and PC phases can take place; these
strongly change the compatibility in the blend and materials having single Tg can
be obtained. FT-IR analyses, coupled with solvent extraction, suggest that a
grafting reaction of PC on PMMA is involved. SEC and DSC data are consistent with
spectroscopic results, and some decrement of the molar weight distribution (MWD)
of PC phase is observed. On the other hand, the presence of a fraction of modified
material having higher MWD of starting PMMA is also noticed. The single Tg
characteristic of some materials has been confirmed by experimental data of
structural relaxation performed by differential scanning calorimetry (DSC). These
materials showed optical clarity and the morphological analysis performed by
scanning electron microscopy (SEM) confirm the homogeneity of these materials.