Co-authors​ :

 Floriane VERCEUX (NORWAY), Sotirios GRAMMATIKOS (NORWAY) 

Plastic recycling is central in the plastic circular economy, allowing for more sustainable end-of-life management of resources. Given that plastic recycling is limited by material performance, which deteriorates during use, as well as due to the recycling process itself. Thus, to improve plastic waste recycling, a better and deeper understanding of the End-of-Life material properties, before and after recycling, is essential. The latter will allow to assess durability, predict long-term behaviour as well as assess further recyclability potential. Depending on their use, thermoplastic polymers are processed using different methods, including additive manufacturing and injection moulding. This study aims to investigate the impact of the manufacturing process on the plastic material’s behaviour during its service life, simulated via accelerated aging. That said, the behaviour of High-Impact Polystyrene (HIPS) used in different home appliances, has been assessed in this study. HIPS coupons were produced by additive manufacturing and injection moulding, fabricating samples of the same material with two different internal structures. Given that HIPS is widely used to fabricate refrigerator inner liners, and as this study seeks to reproduce the real service environment, cyclic freeze-thaw aging was adopted. The effects of freeze-thaw aging on the mechanical, physical, and chemical performance of the HIPS material, were assessed by means of tensile testing, Infrared Spectroscopy (FT-IR), Dynamic Mechanical Analysis (DMA) as well as Scanning Electron Microscopy (SEM) and Computed Tomography scanning (CT-scan). To study the evolution of coupon internal structure as a function of aging, a total of three-hundred-eighty-four freeze-thaw cycles, between minus twenty degrees Celsius and fifty degrees Celsius were employed, assessing the properties of the material after three, six, twelve, twenty-four, forty-eight, ninety-six and one-hundred-ninety-two days, time intervals. A link between physical, mechanical and chemical properties evolution was developed, in an attempt to develop an understanding of the material’s degradation in time and of the effects of the processing method on the durability and long-term performance.