Polystyrene and its products are widely used in various packaging materials

world. He is a thermoplastic and the output ranks third only to polyvinyl chloride and polyethylene. Polystyrene and its products are widely used in various packaging materials, advertising decoration, foam insulation materials, cushioning materials and disposable tableware. However, because PSF is mostly a one-time application, it is prone to waste and its product density is small, bulky, and not easily degradable. In addition, the toxic substances brought by the waste PS foam itself will pollute groundwater to destroy the soil structure and become white pollution. The necessity to recycle and use polystyrene and its products can not only reduce its environmental pollution, but also save resources and achieve economic benefits.

The melt extrusion molding Styrofoam recycling method does not require high equipment, simple process, easy operation, and small investment, and is suitable for general medium and small plants. It is the most mature and most widely used polystyrene foam recycling method. Melt-extrusion molding recycling method is mainly for the waste PSF melt granulation recovery, or dissolve the waste PSF with a solvent, and then through filtration, extrusion and separation of solvent and polystyrene resin. For example, in the process of remolding the polystyrene foam sheet by moulding method, the recycled resin is crushed into fine particles, preheated by steam, and then recompressed and recycled at a certain temperature and pressure to obtain a polystyrene foam sheet, in addition to the apparent density. Slightly higher than the new sheet. Due to the large amount of additives such as fillers and antioxidants in PSF, direct melt granulation will cause a decrease in performance and limit the scope of use, while the solvent recovery method can obtain relatively pure polystyrene raw materials.

The waste polystyrene foam is directly crushed and used as concrete lightweight aggregate. It is made of light-weight concrete material or external wall insulation board with cement and has sound-absorbing and heat-insulating effects. Because PSF is poor in compatibility with cement and poor in dispersibility, surface modification of PSF is required to enhance compatibility. ShinC et al. use waste foamed polystyrene as a raw material to produce sub-micron polystyrene fibers of about 500 nm by electrospinning technology. The nonwoven fabric made of this fiber has excellent filtration performance.