The most popular example of recycling waste plasti

2022-08-04
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Examples of waste plastic recycling

polystyrene foam can be molded into polystyrene beads. Foamed plastics used for packaging household appliances or frozen food; There are also a few instant noodle bowls made of expandable polystyrene beads by injection molding. These plastic products are huge in volume and large in tuition and miscellaneous expenses. Their recycling has received special attention in China

the main ways of recycling polystyrene foams are: granulating after volume reduction, using as various filling materials after crushing, cracking to produce oil or recycling styrene and others

(1) granulation after volume reduction. Polystyrene foam can be melted, extruded and granulated to make recycled pellets. However, due to its huge volume, it is usually necessary to reduce the volume before recycling. The methods include mechanical method, solvent method and heating method

(2) crushed polystyrene foam products can be used as fillers to make various products. For example, ① re molded into foamed plastic products

② concrete composite board products

③ gypsum sandwich brick

④ used as asphalt reinforcement

⑤ used as soil modifier

(3) pyrolysis for oil production or recovery of styrene. The devices for pyrolysis for oil production from waste polystyrene foamed plastic are as follows

waste polystyrene foamed plastic pretreatment heat treatment volume reduction catalytic cracking rectification of styrene

(4) others, Waste polystyrene foams can be used to make coatings and adhesives, etc.

① coatings can be made by adding appropriate solvents after the crushing of expandable polystyrene foams. The process flow is as follows:

fillers, colorants

ps, ethyl acetate back grinding and research to produce

ethyl alcohol, dibutyl ester, ring grinding and filtration reaction kettle grinding filter products

oxygen resin, nitrile rubber kettle

② adhesives, The mixed solvents of esters and benzene, together with waste polystyrene foam, anti sedimentation agent, plasticizer, phenolic resin and other additives, can be used to make coatings for cement, steel and wood

③ bromination is used to prepare brominated polystyrene flame retardant. Aluminum dichloride is used as catalyst to produce brominated polystyrene through electrophilic substitution reaction between waste polystyrene and bromine. The bromine content can reach 60% to 70%. It is used as flame retardant for thermoplastic plastics such as pet, ABS and nylon. Brominated polystyrene is cheap and has good flame retardant effect and thermal stability. It can have obvious flame retardant effect when the dosage is 5 phr (mass). It has good synergistic effect with antimony trioxide

5. recovery of polyurethane

there are many kinds of polyurethane. Its products include soft and hard foamed plastics, thermoplastic elasticity and industrial products, which are widely used in the fields of automobiles, household appliances, chemical industry, daily use and so on. Recycling can be carried out according to the common types

(1) recovery of flexible polyurethane foam. Flexible polyurethane foam can be recovered mechanically. There are ① coating with adhesive and recycling by compression molding ② low temperature recycling as filler

(2) recycling of reaction injection molded polyurethane ① as filler for glass fiber reinforced rim-pur. ② Blended with polypropylene. The flexible PP elastomer can be made from waste RI, which has excellent chemical resistance and colouring performance, light weight m-pur crushed material and PP co concrete. Methods: 1. Activation treatment 2. Adding compatibilizer 3. Adding inorganic filler. ③ The direct compression plastic recycling RIM-PU products meet the relevant requirements of tensile stress relaxation test of steel at room temperature in gb/t 10120 (1) 996 test method for stress relaxation of metals and ASTM E328 (2) 008 test method for stress relaxation of materials and structures and gb/t20065 (2) 006 ribbed steel bars for prestressed concrete. The R recycled materials can be directly pressed and molded into various products without adding adhesives after being crushed and ground. ④ Part of the thermal degradation is recycled. The rim-pur waste is heated in the kneading machine to the degree of fabrication, so that the Pu in the material is broken and degraded in part by 100 tons of sub chains, and the material changes from hard to soft plastic state. At this time, isocyanate is added to crosslink the degraded Pu molecular chains in the material, so as to obtain a hard material, which can be used in automobile tool boxes and other materials with high strength and hardness

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