A new way of recycling PS Foam

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PS foam is a new way of recycling

polystyrene foam is widely used in the packaging of fragile valuables such as instruments, household appliances, handicrafts and fast food because of its light weight, shock absorption, low moisture absorption, easy formation and low price. This kind of packaging material is mostly disposable, with a huge amount of waste. Moreover, because polystyrene has the characteristics of aging resistance and corrosion resistance, it can not be degraded by itself and disappear, resulting in increasingly serious pollution to the environment

there have been many reports on the recycling of polystyrene foams in previous years, mainly using its methods of producing coatings, adhesives, extrusion granulation, cracking and recycling monomers. In recent years, many people have invested a lot of research and put forward many new ways

1. Production of flame retardants. Someone washed and dried the recycled polystyrene foam, dissolved it in organic solvents, and reacted it with liquid bromine to produce brominated polystyrene, a flame retardant. Compared with other organic flame retardants, brominated polystyrene will not release carcinogens such as dioxins during combustion, and it is a flame retardant with good performance. The brominated polystyrene flame retardant prepared by this process is not low in price and equipment quality, and its performance can be comparable to that of commercial brominated polystyrene flame retardant

2. Preparation of impact plastics. In recent years, styrofoam recycling units in Beijing and other places have successfully prepared polystyrene pellets, but the recycled pellets are far inferior to general transparent polystyrene in terms of brittleness, color and transparency. It is necessary to modify it to improve its performance. Some people use linear SBS or sbs/caco3 composite toughener to toughen recycled polystyrene foam. It is found that SBS and polystyrene have good compatibility and dispersion. Adding an appropriate amount of this kind of toughening agent can not only greatly improve the impact strength of recycled polystyrene, but also improve the molding properties of the blends

3. Make light building insulation materials. The waste polystyrene foam is broken into broken particles with a particle size of less than 20mm, then mixed with cement and expanded perlite powder, evenly laid on the roof for curing for 3 days, and leveled with cement mortar after natural drying, so as to make a concrete insulation roof. The roof fully conforms to the provisions of JGJ26-95 "design standard for energy efficiency of civil buildings", and has the advantages of low cost, good insulation effect, light weight, etc., which not only achieves the effect of building energy conservation, but also achieves the purpose of recycling polystyrene foam

4. Defoaming and recovery process of non solvent thermal medium. A difficult problem in the recycling of polystyrene foam is that the transportation cost accounts for a large part of the recycling cost due to its low density. Liu Yingjun and Zhang Songpei introduced the new process of defoaming and recycling with non solvent thermal medium in plastic science and technology. This process is to put the waste polystyrene foam into the defoaming tank, add the thermal medium heated to a certain temperature, make it contact with the foam plastic and fall into the heating storage tank together with the defoaming shrinking material, and then separate the defoaming material from the plastic used in the refrigerator and freezer to obtain the defoaming recycled material. The practical application results show that the process has very significant economic and social benefits

5. Cracking process with high recovery. The pyrolysis of polystyrene has been studied for many years, and its pyrolysis reaction processes have also been reported, including solution degradation, catalytic degradation, metal bath degradation, tubular reactor degradation, etc. In these studies, the yield of styrene is mostly about 60%. In order to improve the influence of styrene degradation reaction, optimized pyrolysis process parameters were obtained to increase the yield of styrene to about 70%

6. Solvent regeneration. Cna mainly designs a solvent regeneration process for waste polystyrene fast food boxes. This process is to dissolve waste polystyrene foam in organic solvents such as aliphatic hydrocarbons or aromatics, put it on hold and remove the precipitated impurities, and then send the solution to the evaporator. The volatile solvent can be recycled after being condensed and recycled in the condenser, and the remaining polystyrene materials can be recycled after being extruded and granulated. Due to the high viscosity and poor fluidity of polymer solution, the volatilization speed of its solvent is relatively slow. The regeneration method developed by Mitsui Shipbuilding Co., Ltd. in Japan uses limonene as solvent, which solves the problem of difficult solvent removal in high viscosity fluid, and can obtain polystyrene regenerated pellets with good performance

7. Regeneration by physical method. Previous recycling methods have a common disadvantage, that is, raw materials must be clean, otherwise it will bring great difficulties to the preliminary work such as cleaning, sorting, separation, etc. It is said that polystyrene foam membrane will gradually become the mainstream material for wet coating in the future, and will be crushed into granular materials. It will be mixed with the filling binder dissolved in the solvent that will be fined for false advertising by organic celebrities, and then re molded at room temperature. There is no need for solvents, heating, and cleaning, sorting, and separation of raw materials. It is simple, energy-saving, and no environmental pollution. With this process, waste polystyrene foam can be prepared into thermal insulation materials and building materials

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