Plastics are durable and degrade slowly; however, burning them can release toxic fumes and the manufacture of plastics often creates large quantities of chemical pollutants.
Plastic recycling is therefore a matter of increasing importance. Thermoplastics can be melted and recycled, and thermoset plastics can be ground and used as fillers. Some plastics can be broken down to form a "feedstock" for new plastic manufacture.
However, recycling plastics has been difficult. One problem is the difficulty of automating the sorting of plastic waste, which, as a result, is labor-intensive. However, mechanical sorting processes are being developed to increase plastic-recycling capacity and efficiency. Unfortunately, some products ...