The Effect of E-Glass Fibers and Phlogopite Mica on the Mechanical Properties and Dimensional Stability of Rigid PVC Foams

Abstract

ABSTRACT THE EFFECT OF E-GLASS FIBERS AND PHLOGOPITE MICA ON THE MECHANICAL PROPERTIES AND DIMENSIONAL STABILITY OF RIGID PVC FOAMS by Murtatha M. Jamel The University of Wisconsin-Milwaukee, 2015 Under the Supervision of Professor Nidal Abu-Zahra Short E-Glass Fibers (GF) and Phlogopite Mica (M) were used separately and simultaneously to enhance the dimensional stability and mechanical properties of extruded rigid Polyvinyl Chloride (PVC) foams. The reinforcing phases were added to rigid PVC compounds at different concentrations and processed using a single screw profile extruder. PVC foam composites were characterized for their dimensional stability, structural, thermal, and mechanical properties. In the first part of this work, two types of short E-glass fibers having different lengths (1/16" and 1/32") were added into rigid PVC foams at different concentrations (0-20 wt.%). Experimental results of PVC foam-Glass Fibers composites (PVC-GF) show that the dimensional stability and storage modulus were enhanced for both fibers length 1/32" and 1/16"by 60% and 65% and 150% and 200%, respectively, and enhancing the heat resistance as well. These improvements were obtained without compromising the tensile and flexural strengths of the composites. Overall, PVC foam-GF composites which were prepared with longer glass fibers exhibit better mechanical and thermal properties than those prepared with shorter glass fibers due to higher interlocking between the fibers and the foam cells, which result in better load distribution in the matrix. In the second part of this work, high aspect ratio Phlogopite mica was added to rigid PVC compounds at different concentrations (0-20 wt. %). Experimental results of PVC foam-Mica composites show that the dimensional stability and storage modulus were enhanced by 44% and 113%, respectively, and heat resistance and tensile strength of the composites were also enhanced with the addition of mica. However, increasing the concentration of mica had no significant effect on the impact and flexural strengths of the composites. SEM micrographs show good dispersion and orientation of mica flakes along the cell walls of the PVC foam. Overall, the platy structure and physical properties of mica seemed to have played an important role in providing good interfacial bonding with the cell membranes of the foam, thus enhancing the dimensional stability of the PVC-Mica foam composites. Finally, short E-glass fibers (1/16") and Phlogopite mica were added as a combination (GM) to rigid PVC compounds at different concentrations. Experimental results of PVC foam-Glass Fibers and Mica composites (PVC-GM) show that the dimensional stability increased by 50% and heat resistance of the samples improved as the amount of reinforcing solids increased in the composites at high glass fibers to mica ratio. The storage modulus, tensile, and flexural strengths of the composites were improved by 220%, 82%, and 46%, respectively. However, the impact strength and the ductility decreased. SEM micrographs show the bonding between glass fiber through the foam cells and a good dispersion and orientation of the mica flakes along the cell walls of the PVC foam.