Influence of nanoclay on the morphology of polypropylene foam

• Main Author: Chan, Weng Wan
• Other Authors: Lu Xuehong
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/74360
• Institution: Nanyang Technological University

Extrusion allows for high volume production of various items such as sheets, tubes and films. The thermoplastic foams are lightweight, have a high strength to weight ratios and good thermal and acoustic insulation. Polypropylene(PP) is a thermoplastic that has good physical and chemical properties and is a potential candidate to be used as a thermoplastic foam to substitute Polystyrene and Polyethylene foams in the market. However, due to polypropylene having weak melt strength it is difficult to process due to the collapse and rupturing of cell walls. The use of nanoclay serves to act as a nucleating agent as well as reinforce the polymer during to foaming process allow for better foam behaviour. Supercritical CO2 is used both as a foaming agent as well as to swell the nanoclay allowing for better dispersion and formation of an intercalated structure which will further strengthen the polymer. A study was conducted on the influence of nanoclay on the morphology of Polypropylene foams in foam extrusion using supercritical CO2 and non-supercritical CO2 as a physical blowing agent. The use of supercritical CO2 in the extrusion foaming of nanoclay composites was able to produce fine cells of less than10um. However, the melt strength of the nanocomposite PP was not able to withstand the foaming process and resulted in cell coalescence. The lowering of screw speeds was an effective means to reduce the cell size of the foams.