Effect of Processing Parameters on Cellular Structures and Mechanical Properties of PMMA Microcellular Foams

Abstract

In this study, the effect of processing parameters on the cellular morphologies and mechanical properties of PMMA microcellular foams is investigated. Microcellular closed cell Poly(methyl-methacrylate) (PMMA) foams were prepared using a two stage batch process method. The foam structure was controlled by altering the processing parameters such as foaming temperature, foaming time and saturation pressure. The foam morphologies were characterized in terms of the average cell size, cell density and foam density. Elastic modulus, tensile strength and elongation at break were studied as functions of the different foaming parameters. The mechanical properties were found to be greatly affected by the foaming parameters and vary with changing the cell morphologies. The experimental results were compared with existing analytical models to validate them and to predict the mechanical properties of microcellular polymeric PMMA foams prepared with different processing parameters. A constitutive equation for the nonlinear elastic behavior of polymeric microcellular foams was developed based on the Maxwell viscoelastic model. The results of this work can help designers optimize the foam processing parameters and achieve desired foam morphology and mechanical properties.