PLASTICPREVENTING ENVIRONMENT FROM PLASTIC

INTRODUCTION

What is Plastics ?

Types of Plastics

Common plastic and uses

History of plastic

Bakelite

Prevention

Control

Reduction

What is plastic ?

Plastic is a material consisting of any of a wide range of synthetic or semi-synthetic organics that are malleable and can be molded into solid objects of diverse shapes. Plastics are typically organic polymers of high molecular mass, but they often contain other substances. They are usually synthetic, most commonly derived from petrochemicals, but many are partially natural.[2] Plasticity is the general property of all materials that are able to irreversibly deform without breaking, but this occurs to such a degree with this class of moldable polymers that their name is an emphasis on this ability.

Due to their relatively low cost, ease of manufacture, versatility, and imperviousness to water, plastics are used in an enormous and expanding range of products, from paper clips to spaceships. They have already displaced many traditional materials, such as wood, stone, horn and bone, leather, paper, metal, glass, and ceramic, in most of their former uses. In developed countries, about a third of plastic is used in packaging and another third in buildings such as piping used in plumbing or vinyl siding.[3] Other uses include automobiles (up to 20% plastic[3]), furniture, and toys.[3] In the developing world, the ratios may be different - for example, reportedly 42% of India's consumption is used in packaging.[3] Plastics have many uses in the medical field as well, to include polymer implants, however the field of plastic surgery is not named for use of plastic material, but rather the more generic meaning of the word plasticity in regards to the reshaping of flesh.

Types of Plastics

plastic

thermoplastic thermosetting plastic

THERMOSETTING AND THERMOPLASTIC

There are two types of plastics: thermoplastics and thermosetting polymers. Thermoplastics are the plastics that do not undergo chemical change in their composition when heated and can be molded again and again. Examples include polyethylene, polypropylene, polystyrene and polyvinyl chloride.[18] Common thermoplastics range from 20,000 to 500,000  while thermosets are assumed to have infinite molecular weight. These chains are made up of many repeating molecular units, known as repeat units, derived from monomers; each polymer chain will have several thousand repeating units.

Thermosets can melt and take shape once; after they have solidified, they stay solid. In the thermosetting process, a chemical reaction occurs that is irreversible. The vulcanization of rubber is a thermosetting process. Before heating with sulphur, the polyisoprene is a tacky, slightly runny material, but after vulcanization the product is rigid and non-tacky.

Common plastic and uses

Polypropylene (PP) – Bottle caps, drinking straws, yogurt containers, appliances, car fenders (bumpers), plastic pressure pipe systems.

Polystyrene (PS) – Packaging foam/"peanuts", food containers, plastic tableware, disposable cups, plates, cutlery, CD and cassette boxes.

High impact polystyrene (HIPS) -: Refrigerator liners, food packaging, vending cups.

Polyamides (PA) (Nylons) – Fibres, toothbrush bristles, tubing, fishing line, low strength machine parts: under-the-hood car engine parts or gun frames.

Acrylonitrile butadiene styrene (ABS) – Electronic equipment cases (e.g., computer monitors, printers, keyboards), drainage pipe.

Polyethylene/Acrylonitrile Butadiene Styrene (PE/ABS) – A slippery blend of PE and ABS used in low-duty dry bearings.

History of plastic

The development of plastics has evolved from the use of natural plastic materials (e.g., chewing gum, shellac) to the use of chemically modified, natural materials (e.g., rubber, nitrocellulose, collagen, galalite) and finally to completely synthetic molecules (e.g., Bakelite, epoxy, Polyvinyl chloride). Early plastics were bio-derived materials such as egg and blood proteins, which are organic polymers. In 1600 BC, Mesoamericans used natural rubber for balls, bands, and figurines.[3]Treated cattle horns were used as windows for lanterns in the Middle Ages. Materials that mimicked the properties of horns were developed by treating milk-proteins (casein) with lye.

Bakelite

The first plastic based on a synthetic polymer was made from phenol and formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was looking for an insulating shellac to coat wires in electric motors and generators. He found that combining phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky mass and later found that the material could be mixed with wood flour, asbestos, or slate dust to create strong and fire resistant "composite" materials. The new material tended to foam during synthesis, requiring that Baekeland build pressure vessels to force out the bubbles and provide a smooth, uniform product, as he announced in 1909, in a meeting of the American Chemical Society.[23] Bakelite was originally used for electrical and mechanical parts, coming into widespread use in consumer goods and jewelry in the 1920s.

Prevention,control and reduction

Just as plastics are a common material used in many aspects of our lives, plastics are also a common component of marine debris. As plastic usage has increased over the years, so has the amount of plastic entering the municipal solid waste stream, more commonly called garbage or trash. Between 1960 and 2007, the amount of plastic in the total solid waste stream increased from 1 to 12%. Plastics are a pervasive environmental problem, but they are a material that can be managed and a resource that can be conserved. Reducing the plastic component of marine debris depends upon better management of this resource.

Plastics are a component of a broad range of marine debris, anything from nets and rope used for fishing to shopping bags and beverage bottles. In the land-based solid waste stream, the largest category of plastics are those used in containers and packaging, such as soft drink

bottles, lids, and shampoo bottles. Plastics are also found in durable (e.g., appliances and furniture) and non-durable goods (e.g., diapers, trash bags, cups, and utensils). Inevitably, some of these goods end up in the ocean. Plastic pellets, or the raw materials used to create plastic products, are also a common marine debris item. These small resin spheres can be lost and carried into the aquatic environment at various stages throughout their creation, transport, and use.

Like all solid waste, the primary strategies for effectively managing plastics arereduce, reuse, and recycle. Source reduction (Reduce and Reuse) can occur by altering the design, manufacture, or use of plastic products and materials. For example, the weight of a 2-liter plastic soft drink bottle has been reduced from 68 grams to 51 grams since 1977, resulting in a 250 million pound decrease of plastic per year in the waste stream. Reusing items prevents waste as it delays or avoids an item's entry into the waste stream and potentially the ocean. Recycling plastics also prevents excess waste by turning materials that otherwise might become marine debris into valuable resources.

In some cases, plastics from household and industrial uses cannot be reused or recycled. Proper disposal and management of these used plastics is necessary to prevent it from being carried into waterways and the ocean. For plastics from household uses this may include ensuring that plastics are properly disposed in a covered receptacle that will not be knocked over. For plastics from industrial uses, controlling plastic includes disposal in appropriately covered receptacles, and ensuring plastics are secured and covered when being transported. Municipalities also play a role in the control of plastics by ensuring that best management practices are followed for waste collection and that landfills are covered and contained.

Disposal of plastic wastes at sea is prevented by both international agreements and domestic legislation. MARPOL Annex V, which is formally called the 1978 Protocol to the 1973 International Convention for the Prevention of Pollution by Ships, established regulations on discharging ship-generated garbage. These regulations include a prohibition on discharging any plastics at sea. Similarly, the Marine Plastic Pollution Research and Control Act (MPPRCA) (33 U.S.C. § 1914) is the domestic legislation that prohibits any ship in U.S. waters from disposing of plastics at sea. Plastics used at sea should be brought back to shore for recycling and other appropriate disposal. Why don’t we recycle???????????????????????

Plastics are a convenient material found in most products that we use every day of our lives. Reducing marine debris, however, depends on improving our control of plastics. Through proper management by individuals and organizations, we can reduce the amount of plastics entering our oceans and conserve this valuable material.

 

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