My Science School

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.

Plastics are polymers, which means that they are made of lots of small molecules joined together to form larger molecules in the form of long chains. Polymers can be manufactured from crude oil, natural gas, or coal. They include artificial fibers and many kinds of plastic. Plastics are extremely useful because they are extraordinarily versatile. They are easy to shape and color. They can be made into rigid objects or thin, pliable sheets. Some plastics are heatproof, while others melt at low temperatures.

Plastic is a material consisting of any of a wide range of synthetic or semi-synthetic organic compounds that are malleable and therefore can be molded into solid objects. Plasticity is the general property of all materials that involves permanent deformation without breaking. Polymers’ name is derived from their flexible and plastic properties.

Plastics are typically organic polymers of high molecular mass, but they often contain other substances. They are usually synthetic and most commonly derived from petrochemicals. However, today’s focus on the environment has led to a growing number of plastics to be derived from renewable materials such as polylactic acid from corn or cellulosic’s from cotton linters.

Plastics have been adopted in a significant, and ever-expanding, range of products thanks to their relatively low cost, ease of manufacture, versatility, and imperviousness to water. They can be found in products as simple as paperclips or as complex as planes.

A large source of diverse plastic material is available across a widespread manufacturing spectrum. One of the most recent and exciting manufacturing domains is in 3D Printing. As new applications for 3D Printing are discovered almost daily, diverse arrays of plastic objects have already been produced using the 3D Printing process. These objects can be found in prototyping labs, toys, mechanical gearboxes, medical prosthetics, and many more. Plastics are generally classified by the chemical structure of the polymer's backbone and side chains.