Downloaded 78 times
More Related Content
Similar to Polymer Recycling & Uses
Polymer Recycling & Uses
- 1. POLYMER RECYCLING &USES TRIPURA UNIVERSITY (A CENTRAL UNIVERSITY) PREPARED BY- Abhijit Debnath M. Tech, 1st Semester Dept. Of Materials Science & Engineering
- 2. INTRODUCTION Plastic is thegeneral common term for a wide range of synthetic or semi synthetic organic solid materials suitable for the manufacture of industrial products. Plastic is one of the few new chemical materials which pose environmental problem. Polyethylene, polyvinyl chloride, polystyrene, PET are largely used in the manufacture of plastics. Plastics are typically polymers of high molecular weight, and may contain other substances to improve performance and/or reduce costs.
- 3. Polymers Thermosets Cannot be melted Thermoplastics Canbe melted Crystalline Amorphous Semi- Crystalline Polystyrene, polycarbonatePolypropylene, LDPE, HDPE Polybutylene terephthalate (PBT), PET CLASSIFICATION OF POLYMER
- 4. TYPES OF PLASTIC PRODUCTS PLASTICBAGS PLASTIC COATINGS PLASTIC FURNITURE PLASTIC SHEETS PLASTIC FITTINGS PLASTIC TANKS PLASTIC TOYS PLASTIC BUCKETS PLASTIC SANITARYWARE PLASTIC STATIONERY source: dipmoldedplastics.com, Google.com
- 5. Plastics pollute beaches& oceans plastic use has increased dramatically, resulting in a huge quantity of nearly indestructible, lightweight material floating in the oceans Plastic bags litter the landscape if they are burnt, they infuse the air with toxic fumes. Source: shutterstock.com PLASTIC’S HARMFUL EFFECTS ON OUR ENVIRONMENT
- 6. Plastic bags killanimals About 100,000 animals such as dolphins, turtles whales, penguins are killed every year due to plastic bags. Plastic bags are non-biodegradable The decomposition of plastic bags takes about 1000 years. picture courtesy: www.onegreenplanet.org
- 7. PLASTIC’S EFFECT ONHUMAN LIFE The major chemicals that go into the making of plastic are highly toxic and pose serious threat to living beings of all species on earth. Some of the constituents of plastic such as benzene are known to cause cancer. Plastic resins themselves are flammable and have contributed considerably to several accidents worldwide.
- 8. Percentage that canbe recycled About 7% of all household waste is plastic. Annually, 3 million tonnes of plastic rubbish are produced. 57% of litter found on beaches is plastic.
- 9. Why recycle plastic? Conservationof non-renewable fossil fuels - Plastic production uses 8% of the world's oil production. Reduced consumption of energy. Reduced amounts of solid waste going to landfill. Reduced emissions of carbon-dioxide (CO2), nitrogen-oxide (NO) and sulphur-dioxide (SO2).
- 10. How are polymersrecycled? 1. Mechanical recycling of plastics refers to processes which involve the melting, shredding or granulation of waste plastics. 2. Plastics must be sorted prior to mechanical recycling. 3. At the moment most sorting for mechanical recycling is done by trained staff who manually sort the plastics into polymer type and/or colour. 4. Following sorting, the plastic is either melted down directly and moulded into a new shape, or melted down after being shredded into flakes and than processed into granules called regranulate.
- 11. Source Reduction Refersto a reduction in the amount of material used in any application The simplest methods to employ source reduction are: • To use fewer products that cause waste • To choose size and types of products where- by waste is minimized • To reduce the material requirements of the product (for manufacturer)
- 12. Recycling of Plastics Reprocessingand refabrication of PCR involves several steps; Collection Handling/sorting Reclamation/sorting End-use fabrication
- 13. Collection Voluntary recycling bythe consumer is the most single factor in improving recycling of all materials However, consumers do not sort their solid waste but rather mix all materials together For many plastics, the cost of virgin plastics is about the same as the cost involve in recycling- create problem in recycling process (different case with recycling of aluminium cans)
- 14. Handling & Sorting Involvesconveying materials from the pickup point (from consumer house) to the reclamation facility. Sorting of materials is necessary (PET bottle, HDPE waste, aluminium alloy, etc) or in broader material groupings (all metals, all plastics, etc). For the highest economy benefit, the HDPE and PET and other recyclable plastics must be separated from the plastics that are not to be recycled- thus considerable labour is required to pick up the recyclables by hand.
- 15. Handling & Sorting Somesorting can be done by machine, i.e. based on certain characteristics (light absorption), various plastic resins can be distinguished from the others. Under certain condition, the mixture of several plastic type can be recycled, called as mixed recycled or comingled recycle. To assist consumers and sorters, Society for plastic Industry (SPI) introduced recycling symbols.
- 16. Numbering system forplastic recycling Recycling No. Abbreviation Polymer Name PETE or PET Polyethylene Terephthalate HDPE High-Density Polyethylene PVC or V Polyvinyl Chloride LDPE Low-Density Polyethylene PP Polypropylene PS Polystyrene OTHER Other plastics, including acrylic, polycarbonate, polylactic acid , nylon and fiberglass.
- 17. Polymer Name Uses Polyethylene Terephthalate Recycled to producepolyester fibres, thermoformed sheet, strapping, soft drink bottles, reinforcement for concrete. High-Density Polyethylene Recycled to become various bottles, grocery bags, recycling bins, agricultural pipe, base cups, car stops, playground equipment, and plastic lumber, flower pot, toys Polyvinyl Chloride Recycled to become pipe, fencing, and non-food bottles. Low-Density Polyethylene Recycled to become plastic bags, various containers, dispensing bottles, wash bottles, tubing, and various molded laboratory equipment. Polypropylene Recycled into auto parts and industrial fibers. Polystyrene Recycled into a wide range of products including office accessories, cafeteria trays, toys, video cassettes and cases, insulation board and styrofoam. Uses of Different Polymers
- 18. Reclamation/Cleaning After sorting, theplastics must be chopped into small flakes or shredded for further processing. Then the flakes are treated with solvents and washed to remove residual contaminants (original content & paper label). The flakes are then sent to the fabricators to extrude into pellets.
- 19. End Uses- SortedPCR The recycled material can be used in the same applications or other applications. However, PCR plastic cannot be used in medical and food-contacting applications due to danger of contamination and disease. Thermoplastic- can be reheated and reprocessed many times (with minor changes in resin properties).
- 20. Degradation Means that theplastic can break down into smaller molecules by natural means, biological agent or by sunlight. In reality, some materials degrade very slowly. Some applications require that the material do not degrade, i.e. packaging material. Some applications need degradable properties, i.e. sutures in medical applications.
- 21. Incineration Incineration orcontrolled burning is another option for disposing of large percent of solid waste. The most common purpose of burning is to generate electricity. Energy content of various solid waste materials and conventional fuels burned to generate electricity.
- 22. Incineration Method Incineration candestroy some types of chemicals that other methods can't. It is also quicker than many other methods.
- 23. Obstacles of Recycling Usage of various copolymer blends (i.e. PET) from different manufacturers do not dissolve into one another when heated. Instead, they tend to phase-separate, like oil and water. Another barrier to recycling is the widespread use of dyes, fillers, and other additives in plastics. The polymer is generally too viscous to economically remove fillers, and would be damaged by many of the processes that could cheaply remove the added dyes. Additives are less widely used in beverage containers and plastic bags, allowing them to be recycled more frequently.
- 24. Recycling plastic usesless water and energy resources than in producing new plastics, and produces fewer greenhouse gases. This is because the polymer chains become damaged or contaminated with food or other types of plastic. What is the effect of recycling plastics? One problem with recycling, however, is that is reduces the strength and versatility of the plastic over time.
- 25. Biodegradable plastics are increasinglybeing used in carrier bags, bin bags and food packaging. One of the problems with traditional plastics is that they do not break down when thrown away. Biodegradable plastics are plastics that can be broken down. They are converted into carbon dioxide, water and minerals by micro-organisms. Biodegradable plastics, such as polylactide, are plant-based polymers. They are often made from starch that has been modified to become more stable. What are biodegradable plastics?
- 26.