The Nature of Plastics and Their Societal Usage
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Published:19 Nov 2018
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H. Millet, P. Vangheluwe, C. Block, A. Sevenster, L. Garcia, and R. Antonopoulos, in Plastics and the Environment, ed. R. M. Harrison and R. E. Hester, The Royal Society of Chemistry, 2018, pp. 1-20.
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The purpose of this chapter is to review the history of plastics, describe the different kinds of plastics, their applications and their benefits, giving several examples of plastics found in our daily lives. The current chapter also provides deep insight into the qualitative characteristics of plastics, while describing their chemical nature in simple terms.
1 Plastics in a Nutshell
The term “plastic” is derived from the Greek words “plastikos”, meaning “fit for moulding” and “plastos” meaning “moulded”. Both terms refer to the material's malleability or plasticity during manufacture, that allows it to be cast, pressed, or extruded into a variety of shapes; such as films, fibres, plates, tubes, bottles, boxes and much more.
In addition, the wide range of possibilities to change their chemical structure or formulations and therefore their final properties allow them to be used in numerous and various applications. We can find them packaging the food that we eat, in the houses we live in, the cars we drive, clothes we wear, the toys we play with and in the televisions we watch. Plastics contribute to our convenience, as well as providing several solutions in our everyday lives, and help to improve the environmental impact of products in many applications.
When it comes to their chemical nature, plastics are synthetic or semi-synthetic materials; they are organic materials, such as wood, paper or wool. Mostly derived from crude oil, they can also be produced from renewable raw materials.
In scientific terms, there are two main categories of plastic materials: thermoplastics and thermoset plastics. Thermoplastics can be heated up to form products, if these end products are re-heated the plastic will soften and melt again. Plastic bottles, films, cups, and fibres are some examples of thermoplastic products. On the other hand, thermoset plastics can be found in products such as electronic chips, dental fillings and the lenses of glasses, they will no longer melt after the “setting” process.
At the end of their useful life, plastic products can either be recycled back into new products or chemical raw materials or, where this is not possible or sustainable, used for energy recovery as a substitute for virgin fossil fuels.
1.1 The History of Plastics
For more than a century, plastics have been providing significant solutions for humans. The development of plastic materials started with the use of natural materials with plastic properties (e.g., chewing gum, shellac), they then evolved with the development of chemically modified natural materials (e.g. rubber, nitrocellulose, collagen, galalith). Finally, the wide range of completely synthetic materials that we would recognise as modern plastics started to be developed around 100 years ago. The first was discovered by Alexander Parkes in 1862 and is commonly known as celluloid today.1
The development of plastic materials passed through various historical phases, becoming today the most widely used material globally. In particular, global plastics production ramped up from 1.5 million tonnes in 1950 to 335 million tonnes in 2016.2
1.1.1 19th Century: The First Polymers
Although it is largely known that plastics are a modern invention, ‘natural polymers’, such as amber, tortoiseshell and horn, are abound in nature. These materials have a similar structure to manufactured plastics and they were often used to replace glass (amber) in the 18th century.
The original breakthrough for the first semisynthetic plastics material – cellulose nitrate – occurred in the late 1850s and involved the modification of cellulose fibres with nitric acid.
Cellulose nitrate had many false starts and financial failures until a Briton, Alexander Parkes exhibited the so-called “Parkesine” as the first world's man-made plastic, in 1862. However, the failure of this product, due to its high manufacturing costs, led to the creation of Xylonite by Daniel Spill. This new material started finding success in the production of objects such as ornaments, knife handles, boxes and more flexible products such as cuffs and collars.
It was in 1869 that an American, John W. Hyatt, made a revolutionary discovery, a process to produce celluloid, a product that could be used as a substitute for natural substances such as tortoiseshell, horn, linen, and ivory. This product entered mass production in 1872.
1.1.2 20th Century: The Revolution of Plastics Starts
Up until the early 1900s, it was impossible to use cellulose nitrate at very high temperatures, because it was flammable. The development of cellulose acetate brought about a solution to this problem, as it started being used as a non-flammable ‘dope’ to stiffen and waterproof the fabric wings and fuselage of early airplanes and was later widely used as cinematographic ‘safety film’. In the meantime, casein formaldehyde was developed, based on fat-free milk and rennin, and used for shaping buttons, buckles and knitting needles. The next years saw a revolution in plastics, making them an integral part of our daily lives.
1.1.3 Beginning of the 20th Century: The Discovery of Bakelite
In 1907, Belgian Leo Baekeland (who coined the term plastic later on), discovered Bakelite, which was largely used in the expanding automobile and radio industries at that time.3
In 1912, polyvinyl chloride (PVC) and polyvinyl acetate (PVA) were discovered by a German chemist, Fritz Klatte. The following year, Jacques E. Brandenbergen, a Swiss engineer, invented Cellophane, a clear, flexible and waterproof packaging material.
1.1.4 1920s: Staudinger and Polymers
In 1921, the first injection moulding press appeared, invented by Arthur Eichengrün.
Meanwhile, a revolution came in 1922, when a German, Herman Staudinger,4 father of macromolecular chemistry, claimed molecules could join to form long chains and therefore become ‘macromolecules’ or polymers. Staudinger provided enough evidence for his macromolecular concept and promoted it, despite the strong opposition of several chemists.
Staudinger provided the theoretical basis for polymer chemistry and significantly contributed to the rapid development of the polymer and plastic industry – which are the reasons why he was awarded with Nobel Prize for chemistry in 1953.
Another important scientific breakthrough occurred in 1927, when Waldo Semon, an American researcher, found a way to plasticise PVC, which had been discovered more than a decade before. PVC was thus converted into a flexible material that could be used for flooring, electrical insulations and roofing membranes. Thanks to this, its real development could start.
1.1.5 1930s: Plexiglas™ and Nylon™ First Appear
In 1930, the commercial production of polystyrene started. In the meantime, Otto Röhm invented a great product in 1933, Plexiglas™, “a crystal-clear, shatter-proof polymethyl acrylate sheet”,5 which found an important market in the aircraft industry.
In 1935, Wallace Carothers from the company DuPont was the first to synthesized Nylon™ (polyamide), which became very famous in stockings. The first commercial PVC products were introduced onto the market in 1934 and 1935, these were flooring and pipes, respectively.
Three years later, a Swiss researcher, Pierre Castan, patented the synthesis of epoxide resins, which were initially used in dentistry (for dental fixtures and castings), as well as medicine. Their properties were also useful as a constituent of glue.
1.1.6 1940s: Large Use of Plastics in World War II
World War II meant a boost for the production and further development of plastics, which took on a key role in the military supply chain. Plastics were used to make almost everything: for example, nylon could be found in parachutes, ropes, body armour and helmet liners, while Plexiglas™ replaced glass in aircraft windows.
A wide variety of pioneering materials, which are still used today, were invented during the wartime period, such as polyethylene, polystyrene, polyester, polyethylene terephthalate, silicones and many more.
1.1.7 1950s: The Spread of Plastics for Domestic Usages
The 1950s saw the growth of plastics for domestic use. Decorative laminates were invented, such as Formica™ tables, which were very popular particularly in the US, and were used in espresso bars and diners. In the same period, plastics also became a major force in the clothing industry. Polyester, Nylon™ and Lycra™ fabrics were easy to wash, needed no ironing and often were cheaper than their natural alternatives.
In 1953, an American chemist named Daniel Fox discovered polycarbonate, a new type of thermoplastic that was very durable and almost bulletproof. Today, it can be found in several modern products, such as smartphones.
1.1.8 1960s: Plastics in the Fashion Industry
The 1960s are known as a decade of mass distribution of stylish, innovative and impressive plastic products in the fashion world, such as soft and hard foams with a protective skin, wet-look polyurethane, transparent acrylic and artificial leather.
Home decoration was also enriched, where unconventional designer furniture such as inflatable chairs and acrylic lights became important for fashion-conscious consumers.
Moreover, plastic materials played an important role in the production of spacecraft components, its lightness and versatility made it irreplaceable for the success of space exploration.
1.1.9 1970s: Plastics Become the Most Used Materials Worldwide
The technological advances during this period would have been impossible without plastics. In engineering and in the computer industry, the new polymers started to replace the use of metals. In healthcare, the hygienic nature of plastics meant that they became extremely important.
1.1.10 1980s: Plastics and the Development of Communication and Transport
The rise of global communications had a direct impact on the production and use of plastics, which provided raw material for the production of personal computers, fibre optic cables and portable telephones.
In transport, the demand for plastics in cars also increased. In the 1980s, the first flight tests of an all-plastic-aircraft took place. Moreover, plastic packaging became very important in shopping, because it helped in the distribution and preserving the quality of the products we buy from supermarkets.
1.1.11 1990s and 2000s: Plastics’ Key Role in Society
Consumer demands for longer product shelf lives and freshness retention led to the development of plastic packaging that has superior barrier properties. Raised awareness in society of the necessity to save fossil fuels increased the need for plastic products, enabling improvement in the energy efficiency of buildings and a reduction in fuel consumption in transportation.
In the 2000s, plastics became key components for meeting challenging societal demands. Used in several applications, plastics are currently essential in the design of structural elements such as insulation, life support systems, space-suit fabric, food packaging, guidance and communication systems, solar panels, and so forth.
2 How Is Plastic Made?
Derived from organic materials, plastics today are mainly made from fossil raw materials. However, the production of plastics only accounts for 4–6% of global oil consumption.6
The production of plastic from crude oil begins in the distillation process of an oil refinery, involving the separation of heavy crude oil into lighter fractions. Each fraction is a mixture of hydrocarbon chains (chemical compounds made up of carbon and hydrogen), which differ in terms of the size and structure of their molecules. One of these fractions, naphtha, is the crucial raw material for the production of plastics. Naphtha is used to generate, through cracking, the different monomers needed (ethylene, propylene, styrene, etc.).
These monomers are the building blocks to produce plastics, through the so-called polymerisation process. The two major polymerisation processes are called polyaddition and polycondensation, and they both require specific catalysts. In a polyaddition process, monomers like ethylene or propylene simply join to form long polymer chains. Polycondensation is the process through which the polymer originates from successive bonds between monomers, with the elimination of a small molecule (water, ammonia, etc.) during the bonding process. Each plastic has its own properties that depend on the various types of basic monomers used, its structure and formulation.
Research and innovation is ongoing to diversify the raw material base to produce plastics. In particular, biomass can be used for the production of so-called bio-based plastics. There are two possible categories of plastics that can be derived from renewable resources. The first one includes similar polymers to those produced from crude oil, but with their monomers being produced from biomass: for instance, sugar cane can serve for the production of ethylene and consequently, polyethylene. The second category includes new polymers derived from new monomers. For example, starch can be used to produce lactic acid and consequently polylactic acid (PLA). In 2017, the global production of bio-based plastics was around 2 million tonnes.7
2.1 The Different Kinds of Plastics
There are different types of plastics that can be grouped into two main polymer families, thermoplastics and thermosets.
Thermoplastics are a family of plastics that can be melted when heated and hardened when cooled. These characteristics, which lend the material its name, are reversible. That is, it can be reheated, reshaped, and hardened repeatedly. This quality also makes them mechanically recyclable.
Thermosets: Thermoset, or thermosetting, plastics are synthetic materials that undergo a chemical change when they are treated, creating a three-dimensional network. After they are heated and formed, these molecules cannot be re-molten and reformed.
2.1.1 Thermoplastics
Thermoplastics can be categorised according to their chemical structural organization and the level of their properties and performances (Figure 1). They represent almost 80% of the plastics demand.
2.1.1.1 Standard Plastics
Standard plastics are the most widely used plastics and account for more than 85% of the global thermoplastics demand (Figure 2).
Polyolefins: They represent the largest family of thermoplastics (55%), which includes all types of polyethylene (LDPE, LLDPE, HDPE) and polypropylene. They are produced mainly from oil and natural gas by a process of polymerisation of ethylene (PE) and propylene (PP) respectively. Thanks to their versatility, polyolefins are used in a very wide range of applications ranging from packaging, automotive, building and construction, medical, sports to consumer goods.
LDPE: is used in cling film, carrier bags, agricultural films, milk carton coatings, electrical cable coatings, and heavy duty industrial bags.
LLDPE: is used in stretch film, industrial packaging film, thin walled containers, and heavy-duty, medium- and small bags.
HDPE: is used in crates and boxes, bottles (for food products, detergents and cosmetics), food containers, toys, petrol tanks, industrial wrapping and film, pipes and houseware.
PP: is used in food packaging, including yoghurt and margarine pots, sweets and snack wrappers, microwave-proof containers, carpet fibres, garden furniture, medical packaging and appliances, luggage, kitchen appliances, and pipes.
Polyvinyl chloride: PVC is the third largest thermoplastic and one of the earliest plastics. It is derived from salt (57%) and oil or gas (43%). It can be either in rigid form, used mainly for the production of pipes and fittings or window-frames, or in soft form such as in flooring or cable applications.
Polystyrene: Polystyrene (PS) is a thermoplastic polymer which can be solid or foamed. It is made from the monomer styrene. It is widely used in packaging, cosmetic packs, toys and refrigerator trays, as well as in many other applications.
Expanded polystyrene: Expanded polystyrene (EPS) is a solid foam with a unique combination of characteristics, such as lightness, insulating properties, durability and an excellent processability. EPS is used in thermal insulation board in buildings, in packaging, cushioning of valuable goods, and in food packaging.
Polyethylene terephthalate: Polyethylene terephthalate (PET) consists of polymerised units of ethylene terephthalate monomers. It is used in fibres for clothing and in containers for foods and beverages.
2.1.1.2 Engineering Plastics
Engineering plastics are a subset of plastic materials, used in applications that generally require higher performance in the areas of heat resistance, chemical resistance, impact, fire retardancy or mechanical strength (Figure 3). They account for 10% of the global thermoplastics demand.
Acrylonitrile butadiene styrene (ABS) is the most frequently used engineering plastic, accounting for one third of the total demand, followed by polyamide (PA), polycarbonate (PC), PET injection (PET), polybutyleneterephthalate (PBT), polyoxymethylene (POM) and polymethylemethacrylate (PMMA). A quarter of global demand comes from the two largest market sectors: electrical and electronic applications and consumer goods, with the transportation industry representing the third largest individual market.
2.1.1.3 High Performance Plastics
This family covers plastics that have a very high mechanical and chemical performance, permitting exceptional end-use applications and specialized niche products. They include Fluoropolymers of which the most common type known is called polytetrafluoroethylene (PTFE). Fluoropolymers are one of the smoothest and toughest materials. Other high performance plastics include; polyimide (PI), polyamide imide (PAI), polyetherimide (PEI), polysulfone (PSU), polyetheretherketon (PEEK), liquid crystalline polymer (LCP), polyphenylenesulfide (PPS) and polyphtaalamide (PPA).
2.1.2 Thermosets
Epoxy resins: Their physical state can be changed from a low viscosity liquid to a high melting point solid, which means that a wide range of materials with unique properties can be made. They are used as an internal lining in food and beverage cans and special packaging, in order to prevent metal corrosion and therefore improve the shelf-life of packed goods. They are also used as a protective coating on everything from beds, garden chairs, office and hospital furniture, to supermarket trolleys and bicycles. Most industries use them in protective coating materials. They are used, for example, in special paints to protect the surfaces of ships and oil rigs from adverse weather, and also in wind turbines.
Polyurethanes: Polyurethane is a polymer composed of organic units joined by carbamate (urethane) links. The majority of polyurethanes are thermosetting polymers that do not melt when heated, but there are also thermoplastic polyurethanes. The main applications are insulated building panels, mattresses and upholstered furniture, car seats, domestic refrigerators and freezers, footwear, and so forth. Other thermoset plastics include phenolic, acrylic, unsaturated polyester and vinylester resins.
2.1.3 Biodegradable Plastics
Biodegradable plastics are plastics that can be degraded by microorganisms into water, carbon dioxide (or methane) and biomass under specified conditions. Biodegradable plastics offer a value proposition, from a waste management perspective, for certain single and/or short-term use applications: such as bags for the collection of organic waste, mulch-films or plant-pots in the agricultural and horticultural sectors, food packaging and disposable tableware (used in closed environments, such as events). An example of a biodegradable plastic is PLA.
3 Usage of Plastics in Our Daily Lives
3.1 Packaging
Packaging represents the main application for plastics and covers about 40% of the European plastics demand (Figure 4).
Flexibility, strength, lightness, stability, impermeability and ease of sterilisation are the main features of plastics that contribute significantly to its commercial success for this application. In this regard, plastics are a preferred packaging material for all sorts of commercial and industrial users.
The taste and quality of foodstuff is not affected by plastics food packaging. In fact, the barrier properties of plastics maintain the organoleptic properties of the food and protects it against external contamination. This feature of plastics is demonstrated in various applications such as packaging films for fresh meats, bottles for beverages, edible oils and sauces, fruit yoghurt cups or margarine tubs.
The main advantages of plastics in packaging are briefly presented in the following sections.
3.1.1 Light as a Feather
Plastic is the lightest packaging material. Although 50% of all packages in Europe are made from plastics, plastic packaging accounts for only 17% of the total packaging weight on the market.8 In addition, this weight has been reduced by 28% over the last 10 years. Lightweight packaging means lighter loads or fewer lorries needed to ship the same number of products, helping to reduce transportation energy, decrease emissions and lower shipping costs. It also contributes to reducing the amount of waste generated.
3.1.2 Food Conservation and Preservation
Plastic packaging protects and maintains perishable food for longer. For instance, the shelf-life of beef can be extended by five to ten days, or even longer, when using the most advanced plastic packaging solutions. Another example is Parmigiano cheese, an expensive product susceptible to spoilage, is packed in a film with high barrier properties, consisting of seven layers of different plastics. If such a complex packaging solution was not available on the market, food producers would have to use far more material to provide an adequate level of protection. In this regard, food waste and the use of preservatives are reduced while the flavour and nutritional value of food are maintained.
3.1.3 Provision of Convenience
Nowadays consumers prefer packaging with clear identification and labelling, that is easy to open and use. Plastic packaging technology has moved forward to provide this, in the near future, packaging is expected to become more intelligent, thanks to multi-functional plastic films and surfaces that can detect and indicate to the consumer the condition of the product, with small, inexpensive chips (RFIDs, based on conductive polymers) that are thin enough to be printed on film. Such ‘smart’ packaging will alert shopkeepers and customers to any temperature changes that may affect the integrity of the product, or when sell-by dates are approaching. Similar chips may help in food preparation, telling the consumer when food has been properly cooked and can be safely eaten.
3.1.4 Safety and Hygiene
Plastic packaging prevents contamination of foods and medicines, helping to prevent the spread of germs during manufacture, distribution and display. Tamper-proof closures provide additional protection and security, while transparent packaging allows people to look at food without having to touch it, cutting down on bruising and other damage.
3.1.5 Environmental Benefits of Plastic Packaging
Thanks to its light weight and its ability to conserve fresh food longer than alternative materials, plastic packaging offers high environmental benefits. If food was packed using materials other than plastics, the related energy consumption would double and greenhouse gas (GHG) emissions would nearly triple.9 This would also be accompanied by a significant increase in the weight of the packaging.
3.2 Building and Construction
Building and Construction is the second largest plastic application after packaging (20% of plastics consumption in Europe). It covers a wide and growing range of applications, where plastic products bring a significant contribution to the reduction of the environmental impacts of buildings, and in particular their energy consumption. In addition to allowing a multitude of functionalities and designs inside the home (flooring, wallpapering, wire sheathing, etc.), some of the most important applications are within the structure of the building, as explained below.
3.2.1 Windows: Saving Energy for Decades
The heat savings offered by modern plastic window profiles, as a result of huge technological progress in recent years, make them the application of choice in low-energy buildings. If the 80 million new windows needed each year in Europe were installed with plastic window frames, the need for five large power stations would be eliminated. In addition, their durability and hardiness mean that high-quality plastic windows can last for over 50 years with little or no upkeep required. This cuts out the cost and time needed to fix or re-paint them, as well as the financial and energy resources involved in replacing them. A further advantage is the variety of design possibilities that plastic window profiles offer. They can come in almost all colours, styles and settings to suit any kind of architecture, from the cutting edge of modern design to renovated historical buildings.
3.2.2 Plastic Pipes
Plastics are a common option for modern water, gas and sewage piping, because of their high resistance to corrosion, their light weight and flexibility, making them particularly durable, easy to install and requiring very little maintenance over time. They help minimize water losses and represent an economically viable solution.
Plastic pipes enable combating of the shortage of drinking water. Often, some areas have too much water, while others have too little. To solve this problem, durable plastic piping systems enable water grids to transport water from reservoirs built with plastics to dry areas.
3.2.3 Insulation
Plastics provide effective insulation from cold, heat and noise. The use of plastic insulation materials enables significant long-term financial and energy savings. Over its lifetime, plastic insulation saves more than 200 times the energy used in its manufacture. In addition, the use of plastics contributes significantly to the reduction of energy and GHG emissions in comparison to other materials. For instance, according to studies,9 the average plastic insulation materials consume 16% less energy and produce 9% less GHG emissions than alternative materials.
The very good intrinsic insulation properties of plastics make plastics insulation efficient, even with a limited quantity of material. Plastics therefore allow optimum use of space, for instance, when sheathing the inner walls of buildings.
Plastic insulation materials are simple to install, highly durable and perform at the same high level over the whole life of the building.
3.3 Transportation
In transport, what matters most is finding the right balance between high performance, competitive pricing, style, reliability, comfort, safety, strength, fuel efficiency and minimal environmental impact. Plastics have revolutionised the construction, performance, safety and functionality of cars. Single mould components have helped manufacturers to decrease vehicle assembly time, quickly introduce design innovations and trim costs. Plastics have helped to make cars lighter, thus reducing fuel demand and GHG emissions.
The aircraft industry is a good example of how plastics and design innovation are closely connected. Since the 1970's, the use of plastics in airplanes has grown significantly.
3.3.1 Saving Energy and Reducing Greenhouse Gas Emissions
The push for lower CO2 emissions is driving research and design efforts in the automotive sector. The use of lightweight plastics in cars allows manufacturers to cut costs, fuel consumption and CO2 emissions: reducing the weight of the bodywork of an average car by 100 kg reduces the CO2 emissions by 10 g km,10 while weight savings from all the plastic parts allows saving of up to 750 litres of oil over the 150 000 km life span of an average car.11
3.3.2 Crucial for Passenger Safety
As cars become lighter there might be a concern that safety is compromised. On the contrary, plastics are actually crucial components in car safety. Energy absorbing plastic bumpers, durable polyester fibre seat belts, high-strength nylon airbags and child restraint plastic seats have all helped to make cars safer for all road users.
3.3.3 Comfort and Cost-effective Design
Today's lightweight, durable plastics give designers and engineers the freedom to create innovative design concepts in vehicles, which enhance passenger comfort at a realistic cost. This extends to the cockpit, surfaces, textiles, lighting and sensors, as well as the car's shape and external accessories like the door handles, mirror frames, wheel covers and rims, and bumpers integrated with the front end.
The full-plastic car is a dream that may come closer to realisation in the approximately the next two decades, although it is unlikely to be achieved by 2030. Plastic bodies may certainly help to reduce the ‘CX factor’, the drag-effect that wind has on a car's body. Furthermore, scientists are already working on a wind-powered towing kite propulsion system for cargo vessels, with the kite being made of high strength, weather-resistant plastic fabrics, for instance.
3.4 Electrical and Electronic
From simple cables and household appliances to smartphones, many of the latest devices created in the electrical and electronic sector capitalize on new generation plastics. Thanks to its manifoldness and versatility, plastics contribute significantly to innovation in the electrical and electronic sector. For this reason, designers of electrical and electronic applications rely on plastics because of their unique features, which are described in the following sections.
3.4.1 Resource Efficiency
Polymers can help the storage of energy for longer. Modern liquid crystal display (LCD) flat screens, well established in society today, consume less power than ordinary screens with cathode ray tubes. Resource efficiency often takes place in invisible parts. This is due to design flexibility of plastics parts inside household equipment, such as a lye container in a washing machine, which reduces water consumption and enables the best eco-efficiency rating, according to the A+++ energy label classification.
3.4.2 Light Weight
In small devices such as smartphones the use of plastics has increased along with the number of different polymer types being used. Smaller, lighter headsets are made possible thanks to plastics.
3.4.3 Resistance
The ability of plastics to isolate electrical current, combined with their resistance to mechanical shocks and stress, as well as flexibility and durability, makes them ideal for vital applications such as safe, reliable and efficient power supplies.
3.4.4 Fire Safety
Where a fire can be ignited from electrical sources, flame retardants offer a large range of solutions for inhibiting ignition – required for product safety through legislation and standards.
Plastics will continue to be a key material in communications, driving further miniaturisation, so that products (mobile-phone earpieces, for instance, perhaps combined with hearing aids) will increasingly be ‘one’ with our bodies.
3.5 Agriculture
For years, the growing use of plastics in agriculture has helped farmers increase crop production, improve food quality and reduce the ecological footprint of their activity. Plastics are a key protagonist in the new agricultural scenario. They can be found as roofs for greenhouses and small tunnels, sheets for mulching, shading nets, bags for hydroponics, pipes for drip irrigation, and sheets for making dams waterproof. In short, they play a major role in the evolution and geographical development of intensive agriculture.
Thanks to plastics, water can be saved and crops can even be planted in desert areas. Plastic irrigation pipes prevent the waste of water and nutrients, rain water can be retained in reservoirs built with plastics, and the use of pesticides can be reduced by keeping crops in an enclosed space such as a greenhouse or, for mulching, under a plastic film. Moreover, the emissions of pesticides into the atmosphere will be reduced as they will stay within the plastic cover.
In the future, the plastics industry will develop more specific films for the food and agriculture industry to maximise yields and enable growth in less than favourable conditions. Given the fact that farming often takes place in rural areas that are also an important tourist amenity, the plastics industry will need to take not only functional factors, but also aesthetic factors into account.
3.6 Medical and Health
Modern healthcare would be impossible without plastic medical products: disposable syringes, intravenous blood bags, tubing and heart valves, and so forth. Plastic packaging is particularly suitable for medical applications, thanks to their exceptional barrier properties, light weight, low cost, durability, transparency and compatibility with other materials.
The life expectancy of humans and the quality of life have increased thanks to modern plastics’ medical breakthroughs that were considered unthinkable 50 years ago and are now regarded as commonplace.
3.6.1 Unblocking Blood Vessels
In the latest heart surgery procedures, thin tubes (catheters) are used to unblock blood vessels, while deposits obstructing them can be broken down with a tiny spiral-shaped implant – a vessel support – positioned in the treated artery, which is made of a plastic developed specifically for the medical field and charged with active substances.
3.6.2 Prosthesis
Plastics are now being used as orthopaedic devices, where they align, support or correct deformities. They can even improve the function of movable parts of the body or replace a body part, taking over its main function. Synthetic materials also play a vital role for diseased arteries that cannot be helped via vessel support. An affected section of the aorta is removed and the gap is bridged by a flexible plastic prosthesis. Thanks to this, the body's lifeline becomes fully functional again.
3.6.3 Artificial Corneas
Eye injuries or chronic inflammations, for example corneal erosion, can impair sight, and if a transplant has little chance of success, a prosthesis is the only hope. Artificial corneas made from a special plastic are now available for treatment. Only 0.3–0.5 millimetres thick, highly transparent, flexible and made of a bio-mechanical material similar to a natural cornea, they can restore clear vision again.
3.6.4 Hearing Aids
People with severely impaired hearing can now have a plastic implant that brings sound back into their ears. This implant consists of numerous components – a microphone, a transmission device connected to a micro-computer worn on the body, a stimulator and an electrode carrier with 16 electrodes for 16 different frequency ranges. As it transforms acoustic impulses into electrical ones, it bypasses the damaged cells and stimulates the auditory nerve directly.
3.6.5 Future of Plastics in Healthcare
There are many areas of healthcare in which plastics could contribute to substantial advances. Magnetic resonance imaging (MRI), for instance, cannot be used in conjunction with metallic surgical tools: as a result, doctors can look at a tumour, but they cannot operate on it under an MRI scanner. This barrier could be overcome by a new plastic robot with no metal or electrical parts. We foresee the use of plastics-based microsystems and nanotechnologies in medicine, with nanopolymers being used as carriers for drugs that directly target damaged cells, and plastic micro-spirals used to combat coronary diseases. Eventually, smart plastics will start to interact directly with our bodies; for instance, scientists are building a new bionic ear coated in smart plastic that boosts the growth of nerve cells in the inner ear when it is charged with electricity. Plastics are also being used in micro-electromechanical systems: these very small plastic devices can be placed on the skin to give instantaneous readings of glucose or lactate levels. Future applications of this technology could include the detection of cancerous cells.
Plastics will play an important role in the development of robotics too. In the healthcare sector, intelligent systems will certainly improve the standards of rehabilitation, they will increase the precision of diagnostics, and they will even provide alternatives to surgery.
3.7 Sport, Leisure and Design
Plastics have revolutionised sports in recent years. From the tracks on which Olympic athletes pursue new records to shoes, clothing, tents and inflatable devices, safety equipment (helmets, kneepads) and stadium construction (water and drainage pipes, seats, roofing), modern sports rely on plastics. Some examples of the applications are detailed below.
3.7.1 Plastics in Ballgames
Plastic materials are used in almost all types of ballgames. Thanks to plastics, football for instance has become faster and more technical than ever before. The newest ball production concept – called thermal bonding and using a high-solid polyurethane layer on a seamless glued surface – results in excellent responsiveness and ball contact sensitivity, a predictable trajectory, substantially reduced water uptake and maximum abrasion resistance.
3.7.2 Plastics in Sports Footwear
Running shoes that weigh just a few grams provide the strength and suppleness that athletes demand. Their power out of the running blocks can make the difference between victory and defeat. Plastics play an important role in today's sports shoe designs, whether the application is running, jumping or hiking.
Take hiking boots for example; the lining and tongue can be made from a loosely woven plastic fabric that repels water and allows moisture to rapidly evaporate from the boot's exterior, keeping the hiker's feet dry in the wet and cool in the heat. For comfort and support, the mid-sole provides lightweight plastic cushioning and the plastic foam padding, on the other hand, provides extra comfort in the insoles.
3.7.3 Plastics in Tennis
Today, sports manufacturers use plastics to make tennis racquets that are light and strong, with excellent shock-absorbing systems. Players now have more powerful racquets with increased ease of manoeuvrability. In some racquet models, the central longitudinal strings lead through a specially developed plastics core that is embedded in a plastics composite, which reduces shock vibration by 45% when the ball hits the racquet. This innovative technology allows tennis enthusiasts at all levels to enjoy the benefits of plastics on their local courts.
3.7.4 Plastics on Water
The mouldability of composite plastics enables sleek dynamic hulls to be produced that are low in weight and high in strength. Power cruisers, sailing yachts and almost every other vessel now has a hull, deck, superstructure and even a mast made of composites.
Today's yachts use advanced carbon fibre compounds that takes yacht racing to a new level. This innovative plastics compound has largely replaced building methods using traditional materials by providing greater flexibility, superior performance and faster production speed.
3.7.5 Plastics and Children
For close to 50 years, the world's toymakers have been using plastics to make some of the best known and most popular toys and products for children. From bicycle helmets and flotation devices to knee guards and other protective sporting gear, plastics help keep children safe, every day. Plastics are one of the most thoroughly tested, well-researched, durable, flexible and cost-efficient materials on today's market.
3.8 Renewable Energies
Plastics play an increasing role in the generation of renewable energy. Examples are the plastic rotor blade of a wind turbine and thin film photovoltaic units, in which semiconductors (metal or organic) are printed on plastic films. More significantly, in wind energy, the GHG emissions savings within the use phase are 140 times higher than the emissions for production, in the event that one third of the GHG savings enabled by the wind power plant are allocated to the rotor. In solar energy, the GHG emission savings during the use phase are 340 times higher than the emissions for production, when one fourth of the GHG savings enabled by the photovoltaic panel are allocated to the plastic film.10
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