Mechanical, morphological, and thermal properties of polypropylene/montmorillonite polymer composite foam

Abstract

The escalating utilization of plastic materials, coupled with advancements in technology, has propelled the plastics industry into a state of continual evolution. However, the rapid technological progress has also exacerbated issues such as environmental pollution and global warming, primarily due to the excessive consumption of raw materials. These environmental challenges have increasingly constrained the growth of the manufacturing sector. In the polymer world, polymer foams, characterized by a high percentage of pores within their structure, have emerged as a new-generation solution for reducing raw material consumption. This study aimed to develop nanoparticle-filled polypropylene (PP)-based polymer composite foams. The original contribution of this study lies in the production and characterization processes of polymer composite foams developed using PP as the matrix material and MMT nano clay as the additive. Optimizing these processes aims to contribute to environmental sustainability goals by reducing raw material consumption. PP/Montmorillonite (MMT) foams were synthesized through melt blending, employing a chemical blowing agent (CBA) and conventional twin-screw extrusion techniques. The resulting composite foams were evaluated for various properties, including density, cell characteristics (such as cell size and cell density), stiffness, thermal properties, and mechanical strength. The presence of microcells within the polymer matrix positively influenced the density of the PP/MMT composite foams. It was observed that tensile properties diminished with increasing content of the blowing agent. The lowest foam density achieved in this study was 0.83 g/cm³. Among the samples, the 3PP/MMT polymer foam exhibited the smallest average cell size (approximately 2 μm) and the highest density (0,87 g/cm³). Nano clay addition generally enhances modulus and strength, while CBA incorporation tends to decrease them. Moreover, elongation at break decreases significantly with increasing CBA and MMT content.

Graphical abstract