Effect of Mixing Sequences on the Flexural and Morphological Properties of Epoxy/ Organo-Montmorillonite Nanocomposites

Abstract

The epoxy nanocomposites were prepared by addition of Organo-montmorillonite (OMMT) varied from 0 to 10 wt%. In-situ polymerization method was used to prepare epoxy/OMMT nanocomposites by three different mixing sequence methods. Method 1 was performed by mixing OMMT with cycloaliphatic amine (curing agent) first, followed by addition of diglycidyl ether-bisphenol A (DGEBA). Method 2 was carried out by mixing the DGEBA with OMMT first, followed by addition of curing agent. In method 3, the DGEBA and curing agent were mixed first, followed by the addition of OMMT. The objective of the research is to study the effects of mixing sequences on the flexural properties and morphology of epoxy/OMMT nanocomposites. The flexural and morphological properties of epoxy/ OMMT nanocomposites were studied by flexural tests, Field Emission Scanning Electron Microscopy, and X-ray Diffraction (XRD). The flexural modulus of epoxy was improved significantly by the incorporation of OMMT. This is attributed to the reinforcement and exfoliation/intercalation of the OMMT. The flexural modulus and strength of epoxy/OMMT nanocomposites prepared by method 3 was relatively higher than that of the composites prepared by method 1 and 2. The XRD results showed the formation of exfoliated structure in the epoxy/OMMT nanocomposites. Sequence of mixing influenced the dispersion and intercalation/exfoliation of the OMMT in the epoxy matrix. Appropriate mixing sequence should be selected in order to achieve better exfoliation of OMMT and higher flexural modulus and strength of the epoxy nanaocomposites.