Morphology and interphase formation in epoxy/PMMA/glass fiber composites: Effect of the molecular weight of the PMMA

► Interphases of epoxy-PMMA (5 wt.%) modified polymer reinforced with GF were studied. ► Four PMMA (Mw = 34,000, 65,000, 76,000 and 360,000 g/mol) were chosen for this work. ► In the presence of GF, a new phase with more restricted mobility appears. ► The amount of this phase increases as molecular weight of PMMA does.