Green Recycling Approach To Obtain Nano- and Microparticles from Expanded Polystyrene Waste

Abstract

In this study, we develop a completely green process that could generate a recycled and value added product of polystyrene (PS), such as micro- and nanosized particles, from waste expanded PS (EPS). The process uses the eco-friendly solvent, d-limonene for dissolving waste EPS. We show the first time use of water as a nonsolvent for the recovery of micro- and nanosized PS particles based on an emulsification–diffusion method. Water forms a low boiling azeotrope with d-limonene and reduces the operating temperatures significantly. Poly­(vinyl alcohol) (PVA), a water-soluble polymer, is used for stabilizing the oil–water emulsion and to control the particle size. The obtained particles were characterized using scanning electron microscopy, FTIR and dynamic light scattering techniques. Effect of PS and PVA concentrations, stirring speed and oil to water (o/w) ratio on the yield and particle size were investigated. The spent solvent was recovered using a distillation process that was carried out along with the emulsification–diffusion, making the process more efficient and sustainable.

Preparation and Properties of Polycarbonate/Polystyrene Bead Alloy via Solvent Evaporation Method

“…Though the solvent used in the study was in quantity, it was shown that about 83.0 À 87.2% of the DCM in the process could be recovered by an evaporation process carried out along with the PC/PS beads formation, which was already a high recovery rate compared with previous study. [31] Preparing PC/PS DCM solution and bad sealed experimental system might cause trace DCM loss. More interestingly, the recovery of solvent had little relation with the addition of PC.…”

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

“…These authors stood out the sustainability of the method. 20 The literature contains several reports on preparation methods that incorporate preformed polymers into emulsied systems, developed as a rst step towards increasing the exposed surface area and permitting processes of polymeric aggregation in non-solvent microphases. A second step involves forming nanoparticles by controlled aggregation and "diffusion-stranding" stabilization of the polymer.…”

“…24 Kwon et al removed the nanoparticles by dialysis to separate the added water from the nanoparticles, 37 while Quintanar et al used distillation, or cross-ow, ltration to eliminate the organic solvent, according to its boiling point, 5 and recovering the solvent by a distillation process. 20 Staff et al prepared nanoparticles of polystyrene by the emulsion-solvent evaporation process, using chloroform, toluene and other solvents. 44 The emulsication-diffusion method by solvent displacement is a modality of the emulsication-diffusion method that consists in carrying out the diffusion phase via direct extraction of the solvent under moderate temperature and reduced pressure.…”

High production-yield solid-state carbon dots with tunable photoluminescence for white/multi-color light-emitting diodes

“…Expanded polystyrene is an inert, hydrocarbon thermoplastic that is extensively used in packaging and thermal insulation. Its low density allows it to escape into the environment easily [8]. The convenient solution of burning waste expanded polystyrene (WEPS) causes air pollution and emits carbon dioxide, which contributes to climate change.…”