Cellular structure of PP/PPma/Palygorskite and its capacity to absorb water

Abstract

The present work studies the effect of Palygorskite content on the water absorption kinetics and cellular structure of polypropylene. These foams were obtained by a single extrusion process (simultaneous formulation and foaming), using as chemical foaming agent: azodicarbonamide at 1%, and maleic anhydride grafted polypropylene as compatibilizer. The cellular structure of the foams was characterized by scanning electron microscopy; also, the water absorption of the foams was measured at long-terms. It was found that the clay content increases cell size and diminishes the nucleation density of the foams; the cellular structure changes from closed cells to open cells. The absorption kinetics is affected by the cellular structure, the presence of micropores in the cell wall and the Palygorskite content. The foam with 1% of clay absorbed the greatest quantity of water.