Recycling of Expanded Polystyrene from Packaging

Abstract

Expanded polystyrene (EPS) is a commonly used polymer in the packaging industry. The great importance of EPS recovery is related to the material's short service life and the high volume of EPS waste. The aim of the present work was to reduce the volume of waste by its mechanical milling and crushing and subsequent reintroduction into mass production. The results of thermal and infrared analysis indicate that the material does not degrade during the recovery process; indeed, the thermal properties of the recycled material are even better than those of the virgin product. Tensile tests showed that the recycled and virgin materials have similar mechanical behaviour. From the results obtained we can conclude that recycled polystyrene can replace virgin polystyrene in some industrial processing, thus reducing the cost of the fi nal product.

Implementation of the emulsification-diffusion method by solvent displacement for polystyrene nanoparticles prepared from recycled material

“…Likewise, a change in the baseline at approximately 100 C was observed, indicating the glass transition of the densied polystyrene, likely due to the evaporation of the gases contained in the cellular structure of this material, which presented a negative slope at lower temperatures. Similar results were reported by Samper et al who observed glass transition temperatures around 105 C for EPS, without observing degradation of the material up to 136 C. 60 Those authors also reported an important fact regarding the glass transition temperature of unprocessed polystyrene particles, which is lower than that for EPS, thus allowing a higher state of thermal resistance of EPS than of unprocessed polystyrene particles. The physical transitions of EPS have also been studied by Mehta et al with results for the density temperature between approximately 110 and 120 C. In comparison, the melting temperature was observed at 160 C. The vaporization temperature was reported to be 275 C, while total volatilization occurred between 460 and 500 C. This allowed us to observe temperature ranges of EPS handling that did not affect the environment when the material decomposed due to the effect of temperature.…”

“…This mechanism allows the particles to form polymer aggregates in drops by interfacial phenomena, which are stabilized by the PVA, thus avoiding fusion and the formation of agglomerates, while remaining at the interfaces. PVA presents an adequate protection effect during the step of forming the PSN, 5,60 which requires a few milliseconds during the diffusion stage of the solvent from the emulsion drops to the aqueous phase of the system. 61 3.2.2.…”

Processing window for extrusion foaming of hydroxypropyl methylcellulose

“…Polyurethane foam comes in a variety of different pore sizes, with hard or soft character, open or closed cell structure and with densities ranging from low values up to about 0.7 g/cm 3 depending on the grade and application (Calvert et al 2010). Commercial EPS often has a density of about 0.01-0.025 g/cm 3 , (Samper et al 2010) and polyethylene foams were reported to have a density of 0.025 to 0.33 g/cm 3 (Biron 2013) depending on production technique. As can be seen from the apparent densities displayed in Fig.…”

Foaming behavior of water-soluble cellulose derivatives: hydroxypropyl methylcellulose and ethyl hydroxyethyl cellulose

“…Commercial polymeric foams such as EPS have a density of about 0.01-0.025 g/cm 3 (Samper et al 2010;Biron 2012) depending on production technique. For PU foams the apparent density is between 0.14 and 0.71 g/cm 3 depending on the grade (Calvert et al 2010).…”