Mechanical, thermal and morphological characteristics of poly(methyl methacrylate) (PMMA) nanocomposites reinforced with Cu-Cr layered double hydroxide

Abstract

The current work deals with the influence of Cu-Cr layered double hydroxide (LDH) on the properties of PMMA nanocomposites. The Cu-Cr LDH was organically modified with sodium dodecyl sulfate (SDS) in order to obtain LDH layers more compatible with polymer chains. PMMA with various quantities of Cu-Cr LDH nanofiller (1-5 wt%) and 5 wt% of polystyrene-grafted maleic anhydride were first melted and extruded in a twin screw extruder and, finally, processed by injection moulding machine to prepare testing specimens. The nanocomposites were examined by X-Ray diffraction (XRD), transmission electron microscope (TEM) and submitted to thermogravimetric (TGA), tensile and hardness testing. The XRD analysis showed an exfoliated structure of the nanocomposites whereas TEM exhibited the intercalated morphology at higher LDH contents. The TGA results revealed that the thermal degradation temperature was enhanced by the incorporation of Cu-Cr LDH. When 50% of the initial sample weight is established as point of comparison, the decomposition temperature of the nanocomposites was increased about 26 - 32 oC with respect to neat PMMA. From the mechanical analysis, it was also observed that PMMA nanocomposite with 1 wt% LDH presented higher tensile strength and hardness than neat PMMA.