Influence of the injection moulding parameters on the cellular structure and thermo mechanical properties of ethylene-propylene block copolymer and PETG foams

Microcellular injection moulding technology is capable of producing lightweight polymeric products. Microcellular foams are characterised by cell densities in the order of 109-1015 cells per cm3 and cell sizes between 10-100 μm in diameter. The foam morphology is determined by the injection moulding parameters, and it has been observed that depending on the parameters variations, cell structure may exhibit substantial morphological differences through the entire section, along the melt flow direction of the injected part. Using a constant temperature profile and blowing agent dosage rate, variations of 3 key injection moulding parameters (mould temperature, injection speed and shot volume) were studied to analyse the effect on foam morphology and thermal mechanical properties of single ethylene-propylene block copolymer (EPBC) and poly(ethylene glycol-co-cyclohexane- 1,4- dimethanol therephthalate) (PETG) specimens.