polymers : plastics and thermoplastics

POLYMERS:

PLASTICS AND RUBBER

MADE BY

$ahil Nagpal (Coordinator)

B.COM(HONS)

232

Date Of Submission

PLASTICA plastic material is any of a wide range of synthetic or semi-synthetic organic solids that are moldable.

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.

Plastics HistoryFirst Plastic - Parkesine

The first man-made plastic was created by Alexander Parkes who publicly demonstrated it at the 1862 Great International Exhibition in London. The material called Parkesine was an organic material derived from cellulose that once heated could be molded, and retained its shape when cooled.

Snapshots of some Parkesine

Materials (First Plastic)

• Celluloid is derived from cellulose and alcoholizedcamphor.

• John Wesley Hyatt invented celluloid as a substitute for the ivory in billiard balls in 1868. He first tried using collodion a natural substance, after spilling a bottle of it and discovering that the material dried into a tough and flexible film.

• However, the material was not strong enough to be used as a billiard ball, until the addition of camphor, a derivative of the laurel tree. The new celluloid could be molded with heat and pressure into a durable shape.

Snapshot of Billiard Balls Made

After Enhancing Parkesine

Formaldehyde Resins - Bakelite

• After cellulose nitrate, formaldehyde was the next product to advance the technology of plastic. Around 1897, efforts to manufacture white chalkboards led to casein plastics (milk protein mixed with formaldehyde) Galalith and Erinoidare two early tradename examples.

• In 1899, Arthur Smith received British Patent 16,275, for "phenol-formaldehyde resins for use as an ebonite substitute in electrical insulation", the first patent for processing a formaldehyde resin.

• In 1899, Arthur Smith received British Patent 16,275, for "phenol-formaldehyde resins for use as an ebonite substitute in electrical insulation", the first patent for processing a formaldehyde resin. However, in 1907, Leo Hendrik Baekeland improved phenol-formaldehyde reaction techniques and invented the first fully synthetic resin to become commercially successful, tradenamed Bakelite.

Snapshot of Materials made from

Bakelite

Timeline - Precursors

• 1839 - Natural Rubber - method of processing invented by Charles Goodyear

• 1843 - Vulcanite - Thomas Hancock

• 1843 - Gutta-Percha - William Montgomerie

• 1856 - Shellac - Alfred Critchlow, Samuel Peck

• 1856 - Bois Durci - Francois Charles Lepag

Timeline - Beginning of the

Plastic Era with Semi Synthetics• 1839 - Polystyrene or PS discovered - Eduard

Simon

• 1862 - Parkesine - Alexander Parkes

• 1863 - Cellulose Nitrate or Celluloid - John Wesley Hyatt

• 1872 - Polyvinyl Chloride or PVC - first created by Eugen Baumann

• 1894 - Viscose Rayon - Charles Frederick Cross, Edward John Bevan

Timeline - Thermosetting

Plastics and Thermoplastics• 1908 - Cellophane ® - Jacques E. Brandenberger

• 1909 - First true plastic Phenol-Formaldehyde tradenamedBakelite - Leo Hendrik Baekeland

• 1926 - Vinyl or PVC - Walter Semon invented a plasticized PVC.

• 1927 - Cellulose Acetate

• 1933 - Polyvinylidene chloride or Saran also called PVDC -accidentally discovered by Ralph Wiley, a Dow Chemical lab worker.

• 1935 - Low-density polyethylene or LDPE - Reginald Gibson and Eric Fawcett

• 1936 - Acrylic or Polymethyl Methacrylate

• 1937 - Polyurethanes tradenamed Igamid for plastics materials and Perlon for fibers. - Otto Bayer and co-workers discovered and patented the chemistry of polyurethanes

• 1938 - Polystyrene made practical

• 1938 - Polytetrafluoroethylene or PTFE tradenamed Teflon - Roy Plunkett

• 1939 - Nylon and Neoprene considered a replacement for silk and a synthetic rubber respectively Wallace Hume Carothers

• 1941 - Polyethylene Terephthalate or Pet - Whinfield and Dickson

• 1942 - Low Density Polyethylene

• 1942 - Unsaturated Polyester also called PET patented by John Rex Whinfield and James Tennant Dickson

• 1951 - High-density polyethylene or HDPE tradenamed Marlex -Paul Hogan and Robert Banks

• 1951 - Polypropylene or PP - Paul Hogan and Robert Banks

• 1953 - Saran Wrap introduced by Dow Chemicals.

• 1954 - Styrofoam a type of foamed polystyrene foam was invented by Ray McIntire for Dow Chemicals

• 1964 - Polyimide

• 1970 - Thermoplastic Polyester this includes trademarked Dacron, Mylar, Melinex, Teijin, and Tetoron

• 1978 - Linear Low Density Polyethylene

• 1985 - Liquid Crystal Polymers

Plastic Products

1.Plastic Garbage Bags

A bin bag or bin liner or garbage bag, or trash bag (American English) is a disposable bag used to contain rubbish (British English) or trash (American English).

2. SILLY PUTTY

Silly Putty is a toy based on silicone polymers which display unusual physical properties. It bounces, but breaks when given a sharp blow and can also flow like a liquid. It contains a viscoelastic liquid silicone, a type of non-Newtonian fluid, which makes it act as a viscous liquid over a long time period but as an elastic solid over a short time period.

3. VELCRO

Velcro is a company that produces the first commercially marketed fabric hook-and-loop fastener typically, two lineal fabric strips. The first component features tiny hooks; the second features even smaller and "hairier" loops. When the two components are pressed together, the hooks catch in the loops and the two pieces fasten or bind temporarily. When separated, by pulling or peeling the two surfaces apart, the velcro strips make a distinctive "ripping" sound.

Types Of Plastics

• The response of a polymer to mechanical forces at elevated temperature is related to its dominant molecular structure.

• One classification of polymers is according to its behavior and rising temperature. Thermoplasticsand Thermosets are the 2 categories.

• A THERMOPLASIC is a polymer that turns to a liquid when heated and freezes to a very glassy state when cooled sufficiently.

• Most thermoplastics are high-molecular-weight polymers whose chains associate through weak Van der Waals forces (polyethylene); stronger dipole-dipole interactions and hydrogen bonding (nylon).

Snapshots of Thermoplastics

Examples of Thermoplastics

More Examples of

Thermoplastics

The effect of Temperature on the

Structure and Behavior of

Thermoplastics

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• Thermoplastic polymers differ from thermosetting polymers (Bakelite, vulcanized rubber) since thermoplastics can be remelted and remolded.

• Thermosetting plastics when heated, will chemically decompose, so they can not be recycled. Yet, once a thermoset is cured it tends to be stronger than a thermoplastic.

• Typically, linear polymers with minor branched structures (and flexible chains) are thermoplastics. The networked structures are Thermosets.

Snapshots of Thermosetting

Plastics

Thermoset Data

Structure Of Thermoplastics and

Thermosets

Thermoplastic v/s Thermosetting

Plastic

Thermoplastic Thermosetting

PlasticLittle Cross Linking Large Cross Linking

Ductile Hard and Brittle

Soften with Heating Doesn’t Soften with Heating

E.G.-Polyethylene,

Polypropylene,

Polycarbonate, Polystyrene.

E.G.-Vulcanized Rubber,

Epoxies, Polyester Resin,

Phenolic Resin.

Manufacturing Of Plastic1. Acquiring the raw material or monomer.

2. Synthesizing the basic polymer.

3. Compounding the polymer into a material that can be used for fabrication.

4. Molding or shaping the plastic into its final form.

Properties Of Plastics• Lightweight

• Resistance to breakage

• Insulating capacity (electrical, thermal and acoustic)

• Ease of handling and safety

• Versatility

• Recyclability

• Usefulness

• Simple, cheap manufacturing

• Impermeability (water, light, gases)

• Does not conduct electricity (excellent for cables, plugs)

Advantages

• It is cheap and easy to buy.

• Hard plastics can be used in making chairs, toys etc.

• Can be putted in other materials and strengthens them.

• Easy to clean and hard to break, you can use it to store water and food.

• Can be used in all types of season and weather even if its summer or raining.

• Can be recycled into another product.

• Can be used in surgeries.

Disadvantages

• It takes a hundred of years to decompose.

• Hard to dispose properly.

• It is made from nonrenewable resources of Earth.

• Can’t stand up because of its lightness.

• Are not biodegradable.

• Number one flood causing material.

• Recycling is very Expensive.

Recycling Plastic

• Plastic recycling is a process in which old plastics is turned into another more useful products. Since plastics can be considered indestructible or simply does not break down easily. It is also the number one trash of humans in landfills which took a lot of space.

• One way to reduce it is to recycle. From the word recycling itself I know you have already an idea what will they do to it. The plastics are brought back to the factories where they do recycling and turned to another products. Some can be turned into trashcans, pots, papers and many more.

Process of Recycling Plastic

Types Of Recycling Processes

1. Mechanical RecyclingThe recycling in which plastics are grouped, then melted, shredded and molded into new shapes creating a new product.

2. Chemical RecyclingThe recycling in which plastics are melted altering

some chemical properties to create a new product.

Biodegradable Plastics

• This is the another way to solve our environmental problems from plastics, this replaces the non-biodegradable plastics into new breed called bioplastic.

• These breed of plastics are commonly made from plants such as corn starch, cane sugar, potato starch and native wild grasses.

• It also helps reducing the use of nonrenewable resources of Earth by using renewable ones which benefits both humans and nature.

• Disposing it properly is the best way to help in reducing pollution and minimizing the dependence on fossil fuels.

Process of Recycling

Biodegradable Plastic

Plastic Recycling SymbolsIn 1988 the Society of the Plastics Industry

developed a numeric code to provide a uniform convention for different types of plastic containers.

These numbers can be found on the underside of containers.

1. PET; PETE (polyethylene terephthalate): plastic water and

Soda bottles.

2. HDPE (high density polyethylene): laundry/dish detergent

3. V (Vinyl) or PVC: Pipes, shower curtains

4. LDPE (low density polyethylene): grocery bags, sandwich

bags

5. PP (polypropylene): Tupperware®, syrup bottles, yogurt

cups,

6. PS (polystyrene): Coffee cups, disposable cutlery

7. Miscellaneous: any combination of 1-6 plastics

RubberRubber can be described in two ways :-

1. Natural rubber is a substance obtained from the milky juice, called latex, produced by a number of different kinds of plants.

2. Synthetic rubber, made by various chemical manufacturing processes, is similar to natural rubber.

Natural Rubber

Natural rubber, also called India rubber or, as initially produced, consists of suitable polymers of the organic compound isoprene, with minor impurities of other organic compounds plus water.

• Currently, rubber is harvested mainly in the form of the latex from certain trees.

• The latex is a sticky, milky colloid drawn off by making incisions into the bark and collecting the fluid in vessels in a process called "tapping".

• The latex then is refined into rubber ready for commercial processing.

• Natural rubber is used extensively in many applications and products, either alone or in combination with other materials.

• In most of its useful forms, it has a large stretch ratio, high resilience, and is extremely waterproof.

Structure Of Natural Rubber

Process of Making Natural Rubber

1. Latex Is Extracted from Trees.

2. Liquid Latex Extracted Is Poured Into a Tray with Spikes So That after Drying Latex can Be easily taken out.

3.The Tray is then put in a Latex Hardening And Drying Machine (LHDM)

4. After Hardening and Getting Dried The Latex We get a Cuboid Of Natural Rubber.

Synthetic Rubber• Synthetic rubber is created from petroleum and is

classified as an artificial elastomer.

• This means that it is able to be deformed without sustaining damage, and can return to its original shape after being stretched.

• Synthetic rubber has many advantages over natural rubber, and is used in many applications due to its superior performance.

• The use of synthetic rubber is much more prominent than natural rubber in most industrialized nations.

Process of Making Synthetic

Rubber• Crude Oil is Extracted.

• Two gases called butadiene and styrene are produced as byproducts during the petroleum refining process.

• Liquid latex, a basic form of synthetic rubber, is created when butadiene and styrene are properly combined.

• After liquid latex is allowed to dry, it can be formed into different shapes and used by manufacturing facilities in place of natural rubber.

Uses of Rubber

Used as Tyres In Automobiles and Airplanes.

Used as Insulators in Electrical Equipments.

Used In Shoes, Stationery, Other Lifestyle products etc.

Properties of Rubber

1. Physical Properties

• Non reactive

• Chemically Resistant to many fluids including many water, weak acids & alkalis

• Non conductive

• Poor conductor of heat & electric

• Elastic

• Tough

• Electric resistant

• Electric insulator

2. Chemical Properties

• Polymers

• Consists of isoprene molecules fitted together in loosed chains

• Consisting long chains of one or more type of molecules

• Contain long chains of hydrogen and carbon molecules

• Rubber go through vulcanization through adding sulfur which result in a hard, durable material with great mechanical properties.

• This create a chemical links between the chains.

Advantages Of Rubber

• Rubber is not only elastic, but is also waterproof and is a good electrical insulator.

• Natural rubber is resilient and is resistant to tearin.

• Some types of rubber are resistant to oils, solvents, and other chemicals.

• SBR (STYRENE BUTADIENE RUBBER) RUBBER provides good abrasion, wear, and tensile qualities.

• Rubber is resistant to ozone, sunlight, oxidation and many petroleum derivatives.

• It also exhibits excellent resistance to ozone, oxidants, and severe weather conditions, thereby making it an outstanding material for outdoor applications.

• Other characteristics include excellent color stability, heat resistance, and dielectric qualities.

Disadvantages Of Rubber

• Low-cost latex products generally shrink.

• Making molds with latex rubber is slow and time-consuming.

• Latex molds are generally not suitable for casting resins.

• Has offensive odour.

• Silicones are generally high in cost. They are also sensitive to substances, and do not have a long library life.

• Polysulfide rubber costs higher than latex.

• Needed to cleaned it often to be kept clean.

• Detergent & other abrasive cleaning liquid which may discolor surface.

• Grease will have a drastic negative effect if not wiped up.

Recycling RubberWhy reclaim or recycle rubber?

Rubber recovery can be a difficult process. There are many reasons, however why rubber should be reclaimed or recovered;

• Recovered rubber can cost half that of natural or synthetic rubber.

• Recovered rubber has some properties that are better than those of virgin rubber.

• Producing rubber from reclaim requires less energy in the total production process than does virgin material.

• It is an excellent way to dispose of unwanted rubber products, which is often difficult.

• It conserves non-renewable petroleum products, which are used to produce synthetic rubbers.

• Recycling activities can generate work in developing countries.

• Many useful products are derived from reused tyres and other rubber products.

• If tyres are incinerated to reclaim embodied energy then they can yield substantial quantities of useful power. In Australia, some cement factories use waste tyres as a fuel source.