Category Plastics

Plastic materials can be shaped very efficiently by machines, so plastic objects are cheaply made in great numbers. Some people think that this has contributed to the “disposable society”, where we are inclined to throw something away when it is worn or broken, instead of trying to mend it, as would have happened in the past. They warn, too, that most plastics do not easily decay, so our thrown-away food cartons and shopping bags will remain to pollute the planet for years to come. However, plastics have also brought great benefits, playing a part in so many aspects of our lives that it is difficult now to imagine the world without them.

There has been no material more revolutionary than modern plastic. Used in almost every single industry in a vast range of ways thanks to its versatility, high durability and ability to be molded into whatever shape necessary, no material has changed (and in many ways, shaped) the world like plastic has.

Since then, plastic took over the world. Thanks to its ability to remain sterile while acting as a container, plastic was used in the formation of bottles for items such as milk, which no longer had to be delivered in glass bottles. In the food industry, plastic has had an amazing, incalculable effect. Raw meat can be kept in plastic packaging to prevent potential diseases, while the use of plastic trays to keep food fresh has helped to diminish waste in stores.

Plastic has had a profound impact on almost every industry it has touched. Medicine benefited greatly from the development of the disposable plastic syringe in 1955, for instance. In fact, if we were to swap plastic for any other material to be used in the same way, it would exponentially increase greenhouse gases being emitted. The effect plastic has had on the nascent industrial world cannot be denied.

Basically, plastics are lightweight, inexpensive and high in quality. Before, buckles are made of metal and are heavier compared to the quick release buckles we use today. Weight really matters a lot in any industry because of storage and shipping issues. It is far easier and lighter to ship plastic buckles than metal buckles, making it more ideal for manufacturers, suppliers, and dealers alike.

Although plastics are considered cheaper, we cannot deny the quality it can offer. Aside from the fact that it is easier to store and ship, manufacturing plastics allow for more flexibility and creativity of the part of plastic manufacturers. Since it is highly malleable, plastics are very easy to customize so practically, any design brought to mind can be manufactured in no time at all!

Take for example plastic spoons and forks. If you will account the cost of damaged or lost utensils, values are probably going to stack up but if you will be using the plastic type, it would the most economical option. Aside from that, you don’t have to wash it with soap and water again and again because it is disposable. Same economics may be applied to quick release buckles too.

Another reason why plastics are preferred over metal is due to is hygienic qualities. It helps prevent the spread of diseases due to improperly cleaned metal cutlery. Now that you know the advantages of using plastics, can you imagine a day in your life without using it more than once? Is it even possible to run your day without it?

Starch, rubber, wool, silk and hair are all natural polymers. Their molecular structure, under the right conditions, makes them strong and flexible.

A polymer is basically synthesized by joining small molecules or substances into a single giant molecule by a chemical process. The small molecules which are used in synthesizing a polymer are called as monomer. Natural Polymers are those substances which are obtained naturally. These polymers are formed either by the process of addition polymerization or condensation polymerization.

Polymers are extensively found in nature. Our body too is made up of many natural polymers like nucleic acids, proteins, etc. The Cellulose is another natural polymer which is a main structural component of the plants. Most of the natural polymers are formed from the condensation polymers and this formation from the monomers, water is obtained as a by-product.

Latex is known to be a kind of rubber, and rubber is a natural polymer. This latex occurs in both the forms either synthetic or natural. The natural form of latex is mainly collected from the rubber trees and it is also found in variety of plants which includes the milkweed. It can also be prepared artificially by the process of building up long chains of molecules of styrene.

Natural rubber, also called by other names of India rubber, latex, Amazonian rubber, caucho, as initially produced, consists of polymers of the organic isoprene, with minor impurities of other organic compounds, plus water. Thailand and Indonesia are two of the leading rubber producers. Types of polyisoprene that are used as natural rubbers are classified as elastomers.

Currently, rubber is harvested mainly in the form of the latex from the rubber tree or others. The latex is a sticky, milky colloid drawn off by making incisions in the bark and collecting the fluid in vessels in a process called “tapping”. The latex then is refined into rubber that is ready for commercial processing. In major areas, latex is allowed to coagulate in the collection cup. The coagulated lumps are collected and processed into dry forms for marketing.

Some plastics, such as polythene, can be melted and reshaped over and over again. These plastics are recyclable and are called thermoplastics. Other plastics are more resistant to heat and cannot be melted and reshaped. They are known as thermoset. Plastic kitchen work-surfaces and the hard plastic casings around some electrical goods are made from thermoset.

Though thermoset plastics and thermoplastics sound similar, they have very different properties and applications. Understanding the performance differences can help you make better sourcing decisions and improve your product designs.

The primary physical difference is that thermoplastics can be remelted back into a liquid, whereas thermoset plastics always remain in a permanent solid state. Think of thermoplastics as butter – butter can be melted and cooled multiple times to form various shapes. Thermoset is similar to bread in that once the final state is achieved, any additional heat would lead to charring.

Thermoset

Thermoset plastics contain polymers that cross-link together during the curing process to form an irreversible chemical bond. The cross-linking process eliminates the risk of the product remelting when heat is applied, making thermosets ideal for high-heat applications such as electronics and appliances.

Thermoset plastics significantly improve the material’s mechanical properties, providing enhances chemical resistance, heat resistance and structural integrity. Thermoset plastics are often used for sealed products due to their resistance to deformation.

Thermoplastics

Thermoplastics pellets soften when heated and become more fluid as additional heat is applied. The curing process is completely reversible as no chemical bonding takes place. This characteristic allows thermoplastics to be remolded and recycled without negatively affecting the material’s physical properties.

There are multiple thermoplastic resins that offer various performance benefits, but most materials commonly offer high strength, shrink-resistance and easy bendability. Depending on the resin, thermoplastics can serve low-stress applications such as plastic bags or high-stress mechanical parts.

Plastic may be shaped in various ways. It can be extruded (pushed through a nozzle when liquid) to form sheets, tubes and fibers. Molten plastic can be poured into moulds. Vacuum forming is a way of making complicated plastic shapes. A sheet of warm plastic is placed over a mould, and then the air is sucked from under it so that the sheet is pulled firmly against the sides of the mould. When the plastic is cooled, it retains the mould’s shape. Disposable cups are often made in this way.

Metalworking using machines and machine tools includes cutting using a lathe, plastic forming, and welding. When grouped with other such metalworking techniques, plastic forming is also called stamping and makes the designed shapes by pressing the material into a die. This processing method utilizes the plasticity—the characteristic that a material remains in the shape it is changed to by the application of a certain force—of metals and other solids. Plastic forming is primarily used in the metalworking of steel materials such as those for automobile parts. Unlike cutting with a lathe, this method does not produce chips and also allows mass production of the same parts through mold pressing.

There are two types of plastic forming: Cold-plastic forming, which is performed at ambient temperatures, and hot-plastic forming, which uses heat. When heated, metal undergoes thermal expansion and changes shape. As such, cold-plastic forming is used whenever possible and hot-plastic forming is used only when the material of the target being produced is hard.

Some examples of other types of plastic forming include forging for manufacturing nuts and bolts; extrusion, wire drawing, and pultrusion for forming wire materials and pipes; deep drawing for creating spherical surfaces in metal sheets; bending for producing leaf springs; riveting for securing assemblies in place; and shearing for cutting metal sheets.

Almost anything can be made from plastic! Plastic packaging keeps food fresh and protects it from bacteria. A plastic coating, called Teflon, can prevent food from sticking to cooking pans. Plastic can be elastic, like the skin of a balloon, or very rigid and reinforced with other fibers, as in a protective helmet. Plastic can also be a good insulator. A plastic sleeve on electrical wiring protects the wires from corrosion and the user from electric shocks. Polystyrene packaging can help to keep take-away food warm. Plastic can be dyed in bright colours or completely transparent, to make spectacles and contact lenses. Without plastics, there would be less music in our lives, with no cassette tapes, compact discs or even old-fashioned records.

Plastic, polymeric material that has the capability of being molded or shaped, usually by the application of heat and pressure. This property of plasticity, often found in combination with other special properties such as low density, low electrical conductivity, transparency, and toughness, allows plastics to be made into a great variety of products. These include tough and lightweight beverage bottles made of polyethylene terephthalate (PET), flexible garden hoses made of polyvinyl chloride (PVC), insulating food containers made of foamed polystyrene, and shatterproof windows made of polymethyl methacrylate.

Many of the chemical names of the polymers employed as plastics have become familiar to consumers, although some are better known by their abbreviations or trade names. Thus, polyethylene terephthalate and polyvinyl chloride are commonly referred to as PET and PVC, while foamed polystyrene and polymethyl methacrylate are known by their trademarked names, Styrofoam and Plexiglas (or Perspex).

Industrial fabricators of plastic products tend to think of plastics as either “commodity” resins or “specialty” resins. (The term resin dates from the early years of the plastics industry; it originally referred to naturally occurring amorphous solids such as shellac and rosin.) Commodity resins are plastics that are produced at high volume and low cost for the most common disposable items and durable goods. They are represented chiefly by polyethylene, polypropylene, polyvinyl chloride, and polystyrene. Specialty resins are plastics whose properties are tailored to specific applications and that are produced at low volume and higher cost. Among this group are the so-called engineering plastics, or engineering resins, which are plastics that can compete with die-cast metals in plumbing, hardware, and automotive applications. Important engineering plastics, less familiar to consumers than the commodity plastics listed above, are polyacetal, polyamide (particularly those known by the trade name nylon), polytetrafiuoroethylene (trademark Teflon), polycarbonate, polyphenylene sulfide, epoxy, and polyetheretherketone. Another member of the specialty resins is thermoplastic elastomers, polymers that have the elastic properties of rubber yet can be molded repeatedly upon heating.

          The first plastic-type material was unveiled by Alexander Parkes at the Great International Exhibition in London in 1862. Parkes claimed that his new material could do anything that rubber was capable of, but at a much lower price. This material could be moulded into thousands of different shapes.

Cellophane

In 1913, Dr Jacques

Edwin Brandenberger invented a wipeable surface by adding a clear, flexible film to cloth. Brandenberger invented cellophane. Now it is widely used for packaging and is a fully flexible, waterproof wrap.

Bakelite telephone

In 1907, a New York chemist, Leo Bakeland, created a liquid resin which he named Bakelite. This resin could be moulded into any shape and it would not burn, boil or melt when it was set. Bakelite was the first thermosetting plastic which would always keep its shape and form.

V Kevlar

In a laboratory in 1965, two research scientists created a new fibre. They named it Kevlar. It was strong, light and flexible. Today it is used for sports equipment, bullet-proof vests and for ropes used on the expedition to Mars.

Nylon stockings

In 1939, nylon stockings were unveiled and were extremely popular with many women during the war years (1939-1945). Nylon replaced animal hair in toothbrushes, and silk in stockings.

Velcro

In 1957, George de Maestral was so impressed with the way that cocklebars — a type of vegetation — used thousands of tiny hooks to cling to anything, he invented a product, using nylon, that would replicate this natural phenomenon. He called it Velcro.

          Plastics have so many uses and many also have different names. These names include the brand names, trade names, manufacturers’ names and the inventor’s name. The unique characteristics of plastics mean that an enormous variety of products can be made, such as hard and flexible sheets, foams and fabrics as well as moulded objects. Plastics are an important part of everyday life.

          The world is full of plastics. Whether you realize it or not, practically everything you see and use on a daily basis is entirely or partly plastic material. Your television, computer, car, house, refrigerator, and many other essential products utilize plastic materials to make your life easier and more straightforward.  However, all plastics are not made alike. Manufacturers utilize a variety of different plastic materials and compounds that each possesses unique properties. 

1. Acrylic or Polymethyl Methacrylate (PMMA)

Well-known for its use in optical devices and products, acrylic is a transparent thermoplastic used as a lightweight, shatter-resistant alternative to glass. Acrylic is typically used in sheet form create products such as acrylic mirrors and acrylic plexiglass. The transparent plastic can be made colored and fluorescent, abrasion-resistant, bullet-resistant, UV-tolerant, non-glare, anti-static and many more. In addition to being than glass and polycarbonate sheeting acrylic is seventeen times more impact resistant than glass, easier to handle and process, and has endless applications.  

2. Polycarbonate (PC)

Tough, stable, and transparent, polycarbonate is an excellent engineering plastic that is as clear as glass and two hundred and fifty times stronger. Thirty times stronger than acrylic, clear polycarbonate sheets are also easily worked, molded, and thermo-formed or cold-formed. Although extremely strong and impact-resistant, polycarbonate plastic possesses inherent design flexibility. Unlike glass or acrylic, polycarbonate plastic sheets can be cut or cold-formed on site without pre-forming and fabrication. Polycarbonate plastic is in a wide variety of products including greenhouses, DVDs, sunglasses, police riot gear, and more.             

3. Polyethylene (PE)

The most common plastic on earth, polyethylene can be manufactured in varying densities. Each different density of polyethylene gives the final plastic unique physical properties. As a result, polyethylene is in a wide variety of products.  

• Low-Density Polyethylene (LDPE)

This density of polyethylene is ductile and used to make products like shopping bags, plastic bags, clear food containers, disposable packaging, etc.  

• Medium-Density Polyethylene (MDPE)

Possessing more polymer chains and, thus, greater density, MDPE is typically in gas pipes, shrink film, carrier bags, screw closures, and more.

• High-Density Polyethylene (HDPE)

More rigid than both LDPE and MDPE, HDPE plastic sheeting is in products such as plastic bottles, piping for water and sewer, snowboards, boats, and folding chairs.    

• Ultra High Molecular Weight Polyethylene (UHMWPE)

UHMWPE is not much denser than HDPE. Compared to HDPE, this polyethylene plastic much more abrasion resistant due to the extreme length of its polymer chains. Possessing high density and low friction properties, UHMWPE is in military body armor, hydraulic seals and bearings, biomaterial for hip, knee, and spine implants, and artificial ice skating rinks. 

 

4. Polypropylene (PP)

This plastic material is a thermoplastic polymer and the world’s second-most widely produced synthetic plastic. Its widespread use and popularity are undoubted because polypropylene is one of the most flexible thermoplastics on the planet. Although PP is stronger than PE, it still retains flexibility. It will not crack under repeated stress. Durable, flexible, heat resistant, acid resistance, and cheap, polypropylene sheets are used to make laboratory equipment, automotive parts, medical devices, and food containers. Just to name a few.  

5. Polyethylene Terephthalate (PETE or PET)

The most common thermoplastic resin of the polyester family, PET is the fourth-most produced synthetic plastic. Polyethylene Terephthalate has excellent chemical resistance to organic materials and water and is easily recyclable. It is practically shatterproof and possesses an impressive high strength to weight ratio. This plastic material is in fibers for clothing, containers for foods and liquid, glass fiber for engineering resins, carbon nanotubes, and many other products that we use on a daily basis.  

6. Polyvinyl Chloride (PVC)

The third-most produced synthetic plastic polymer, PVC can be manufactured to possess rigid or flexible properties. It is well-known for its ability to blend with other materials. For example, expanded PVC sheets are a foamed polyvinyl chloride material that is ideal products like kiosks, store displays, and exhibits. The rigid form of PVC is commonly in construction materials, doors, windows, bottles, non-food packaging, and more. With the addition of plasticizers such as phthalates, the softer and more flexible form of PVC is in plumbing products, electrical cable insulation, clothing, medical tubing, and other similar products.  

7. Acrylonitrile-Butadiene-Styrene (ABS)

Created by polymerizing styrene and acrylonitrile in the presence of polybutadiene, ABS is robust, flexible, glossy, highly processable, and impact resistant. It can be manufactured in a range of thicknesses from 200 microns to 5mm with a maximum width of 1600mm. With a relatively low manufacturing cost, ABS plastic sheeting is typically used in the automotive and refrigeration industries but is also in products such as boxes, gauges, protective headgear, luggage, and children’s toys.  

Plastics are derived from natural resources — oil, coal and natural gas. We are using oil so fast that the Earth’s supplies may run out within 100 years. If they do, so will plastics. Scientists are investigating new ideas for making plastics by processing plants such as the sweet potato, bamboo and flax. .61 Using organic raw materials to make plastics would be kinder to the environment. Items such as a car would be easier to dispose of. If a car was made of organic raw materials most of the parts would naturally rot. Instead of scrapping it, you may just end up eating it!

Wildlife

Plastics can be extremely hazardous to wildlife. Each year, many birds become entangled in plastic drinks can holders. Once the plastic is wrapped around a bird’s neck or feet, it is difficult to escape. This causes panic and, ultimately, death.

Pollution

 The Trabant emerged in the 19505 as one of the first cars to be made almost entirely out of plastic. While its benefits included value for money and a vehicle that would not easily rust, it also had its downfalls. The plastic used on this car would not breakdown naturally in the environment and so disposal was difficult. Unfortunately, the Trabant added to the mass waste in landfill sites.

Re-using

Large water containers like these can be re-used many times. This is far more considerate to the environment than disposing of numerous smaller bottles each time you have a drink. it’s also a good idea to donate old computers, compact discs, video tapes, toys and household goods to charity shops for re-use.

Alternative sources

Plastics are made from natural resources that are not renewable. These resources are rapidly running out. Alternative sources such as soya beans and sugars can be processed into plastic products, saving our valuable non-renewable sources.

Picture Credit : Google

Plastics are used to make synthetic fabrics for clothes, curtains, sheets and carpets. Nylon, polyester and acrylic are all plastic fabrics. They are made from thermoplastics. You may wonder why it is necessary to make synthetic fabrics when there are natural ones, like cotton and wool. The answer is that natural fabrics from raw materials are expensive and in short supply.

Clothes made from synthetic fabrics have other advantages such as they do not crease much. However, they are not so comfortable to wear, or as warm, as natural fabrics. Synthetic fabrics are often mixed with natural ones to combine the advantages of both.

A Synthetic Fibre is a chain of small units of chemical substance joined together. Many such single units combine to form single unit called Polymer. Polymer means made of many units joined together.

 Types of Synthetic Fibre

       Rayon– Rayon is synthesized from wood pulp. Rayon resembles silk, so it is also known as artificial silk. Rayon can be dyed in different colours and is much cheaper than silk.

       Nylon– Nylon was first commercially synthesized fibre. Nylon is synthesized from coal, water and air. Nylon is very strong and its fabric is like silk.

       Polyester– Polyester, one of the most popular man-made fibres. It is made of repeating unit of a chemical called ester. It is widely used to make clothes.

       Acrylic– Acrylic is a man-made fibre. Acrylic is known as artificial wool or synthetic wool because it resembles wool. Acrylic is cheaper than natural wool and can be dyed in various colours. This makes acrylic is very popular among other fabrics.

Characteristics of Synthetic Fibres

       Synthetic fibres are cheaper than natural fibre.

       Synthetic fibres are stronger than natural fibre.

       Synthetic fibres are more durable than natural fibre.

       Synthetic fabrics are dried up in less time.

       Synthetic fibres are easy to maintain and wash.