History of Synthetic Polymers

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Questions and Answers

What was the significant outcome of Christian Schoenbein's work with cellulose?

He created guncotton, a smokeless explosive. (correct)

He developed a method for sustainable rubber production.

He discovered natural polymers in tree sap.

He invented celluloid as a substitute for plastic.

Which process is responsible for maintaining the resilience of rubber?

Polymerization

Phosphorylation

Hydrogenation

Vulcanisation (correct)

What combination was used to produce celluloid in 1869?

Crude rubber and camphor

Polyisoprene and sulphur

Camphor and nitrocellulose (correct)

Nitric acid and cellulose

What application was NOT a result of celluloid production?

Styrofoam containers Signup and view all the answers

What is a characteristic of the first artificial polymers?

They included modifications of naturally occurring polymers. Signup and view all the answers

What is the main cause of photochemical smog?

Interaction of sunlight with pollutants Signup and view all the answers

Which of the following is considered a volatile organic compound (VOC)?

Benzene Signup and view all the answers

What type of pollution results from the accumulation of suspended particles in a body of water?

Sedimentary pollution Signup and view all the answers

Which method reduces the volume of solid waste by combustion?

Incineration Signup and view all the answers

What is a characteristic of persistent organic pollutants (POPs)?

They can bioaccumulate in the food chain Signup and view all the answers

What is the definition of eutrophication?

Selective stimulation of plant life over animal life Signup and view all the answers

Which of the following is a potential consequence of DDT in the environment?

Interference with animal reproduction Signup and view all the answers

Which pollution source is primarily associated with municipal solid waste?

Households and businesses Signup and view all the answers

What is a defining feature of addition polymers?

They retain all atoms originally present in the monomer units Signup and view all the answers

Which statement best describes biopolymers?

They are produced by living organisms Signup and view all the answers

Which type of polymerization involves the release of small molecules like water during formation?

Condensation polymerization Signup and view all the answers

What category does polyethylene belong to?

Addition polymer Signup and view all the answers

Which plastic is commonly used for food-storage containers?

Polyethylene Signup and view all the answers

What characteristic do all synthetic polymers share?

They possess high durability and resistance to decomposition Signup and view all the answers

Which of the following is NOT a common use of polystyrene?

Plastic automotive parts Signup and view all the answers

What is the Greek origin of the term 'plastic'?

It means to mold and shape Signup and view all the answers

What type of monomers are used to create copolymers?

Two or more different kinds of monomers Signup and view all the answers

Which of the following statements is true about polyethylene terephthalate (PET)?

It is a clear plastic used for water and soft drink bottles Signup and view all the answers

Which of the following monomers undergoes addition polymerization to form polypropylene?

Propylene Signup and view all the answers

What describes the molecular structure of a typical synthetic polymer molecule?

Contains thousands of linked monomers Signup and view all the answers

Which property makes plastics a popular choice for a variety of applications?

Their range of properties from firm to flexible Signup and view all the answers

Which of the following is a key feature of vinyl chloride?

It is polymerized to form polyvinylchloride (PVC) Signup and view all the answers

What characterizes homopolymers?

They consist of chains produced from a single type of monomer. Signup and view all the answers

Which factor does NOT influence the physical properties of polymers?

The temperature of manufacturing Signup and view all the answers

What is the primary difference between low density polyethylene (LDPE) and high density polyethylene (HDPE)?

LDPE is composed of branched chains while HDPE has linear chains. Signup and view all the answers

Which type of plastic hardens permanently upon heating and cannot be re-shaped?

Thermosetting plastics Signup and view all the answers

What is the main characteristic of neoprene?

It is a homopolymer produced from chloroprene. Signup and view all the answers

Bakelite is classified as which type of polymer?

Condensation polymer Signup and view all the answers

What is polylactic acid (PLA) primarily derived from?

Starch from corn or other plants Signup and view all the answers

Which statement about recycling plastics is NOT true?

All plastics carry the same resin code number. Signup and view all the answers

Which type of pollution is defined as an excess of a substance due to human activity?

Anthropogenic pollution Signup and view all the answers

Primary air pollutants are generated as a result of what?

Direct human activity Signup and view all the answers

What is a major environmental issue related to plastic waste?

Most plastic waste ends up in landfills. Signup and view all the answers

Which of the following statements regarding elastomers is correct?

They can return to their original shape after deformation. Signup and view all the answers

What feature distinguishes thermoplastics from thermosetting plastics?

Thermoplastics can be reheated and reshaped. Signup and view all the answers

Study Notes

UGEB2380 - The Chemistry of Life

Course title: The Chemistry of Life
Academic year: 2024-25
Lecturer: Dr. Sam CK HAU (Department of Chemistry)

Plastics, Pollution, and Sustainability

Subtopic explores plastics, pollution, and sustainability.

Polymer Discovery

First artificial polymers: Semi-synthetic, produced through chemical modification of naturally occurring polymers (e.g., cellulose in cotton).
Guncotton (1845): Swiss chemist Christian Schoenbein invented guncotton by reacting cellulose with nitric acid, converting some hydroxyl groups into nitrate groups. Used as a smokeless explosive.
Celluloid (1869): John Wesley Hyatt created celluloid by combining camphor with a lightly nitrated form of nitrocellulose. A substitute for ivory, used in dentures, photographic film, combs, brush handles, and ping-pong balls.
Vulcanized rubber (1839): American inventor Charles Goodyear accidentally mixed crude rubber with sulphur on a hot stove. This created cross-links between polymer chains, making the rubber more resilient. This process is known as vulcanization.

Polymer Uses and Structures

Versatile plastics: Exhibit wide range of properties, from firm/rigid to soft/flexible; relatively light and inexpensive.
Limitless shapes and objects: Can be molded into a wide variety of shapes and objects.
Durable and resistant to decomposition: Often quite durable and resistant to breaking down.
Massive production: About 300 million tons of various plastics are produced globally each year.
Polymers: Large molecules (macromolecules). Made up of repeated smaller molecules (monomers).
Polymer structures: Polymer structures can be linear, branched, cross-linked, or networked.

Polymer Uses and Structures (continued)

Synthetic polymers: Produced in laboratories or factories from monomers.
Biopolymers: Produced by living organisms (e.g., starch, cellulose, DNA molecules).

Polymer Formation

Addition polymers: No atoms are lost during polymerization. Monomer units retain their original atoms. Unsaturated monomers (double or triple bonds) link to neighboring monomers via covalent bonds. Examples - Polyethylene; formed by polymerization of ethylene or one of its derivatives.
Condensation polymers: Creation of a new link in the growing polymer chain is accompanied by the release of a small molecule (e.g., water or alcohol). Examples - Polyethylene terephthalate (PET), Nylon,

Polymer Formation (Polymerisation)

List of examples of various types of produced polymers (Ethylene, Polyethylene, Propylene, Polypropylene, Styrene, Polystyrene, Vinyl Chloride, Polyvinyl chloride, Tetrahydrofluoroethylene, Polytetrafluoroethylene).

Copolymers and Homopolymers

Copolymers: Consist of two or more monomers.
Homopolymers: Consist of one type of monomer

Properties of Polymers

Properties depend on: Monomer structure, average polymer chain length, chain architecture (linear or branched), and presence of additives (e.g., plasticizers).
Additives: Can affect flexibility and other properties.

LD and HD Polyethylene

LDPE: Lower density, more flexible, disorganised branched chains, used for plastic wrap and squeeze bottles
HDPE: Higher density, stronger, linear chains, used for beverage bottles and other consumer products

Plastic Category

Thermoplastics: Soften when heated and harden when cooled.
Thermosets: Soft and moldable initially, but become permanently hard and won't soften when heated further (may decompose at high temperatures)
Elastomers: Elastic polymers that return to their original shape after stretching or squeezing.

Synthetic Rubber

Styrene-butadiene copolymer: Common synthetic rubber; used in tires, automotive parts, and other goods
Neoprene: A homopolymer produced from chloroprene; more resistant to heat and organic solvents; used in wetsuits
Bakelite: First synthetic polymer widely used; hard and resistant to heat and electricity. Made from phenol and formaldehyde.

Synthetic Rubber (continued)

In 1935, Wallace Carothers created nylon-6,6 by mixing monomers; used in various applications from clothing, to military supplies.

Plastic and Sustainability

Environmental costs: Significant environmental costs associated with plastic production and disposal from non-renewable resources
Waste disposal: Plastic waste does not decompose readily; significant amounts of waste end up in landfills, causing pollution & generating toxic gases during incineration
Recycling Issues: Only a small percentage of plastic is recycled; confusion about the recycling processes.

Recycling

Resin codes: Numbers assigned to aid in classifying and recycling plastics
Sorting and processing: Plastics are sorted by type, cleaned, and shredded, then melted into granules that can be sold

Bioplastic

PLA (Polylactic Acid): Produced from starch derived from corn or other plants, a thermoplastic; biodegradable in composting facilities.
Substitution for PET: Can potentially replace PET in certain applications.
Biodegradation time: Takes several months to biodegrade; only small amounts directed to composting due to processing costs

Pollution and Wastes

Definition of pollution: An excess of a substance (from human or natural sources) present in the wrong environmental location.

Air Pollution

Primary pollutants: Substances released directly from a specific activity. Examples - CO, CO2, SO2, NO, and NO2 released by burning fossil fuels
Secondary pollutants: Pollutants produced from reactions involving primary pollutants. Example - SO3, HNO3, H2SO4 produced from reactions between water, NO_x, or SO₂, O₃.
Photochemical smog: Complex combination of pollutants resulting from sunlight interacting with nitrogen dioxide (NO₂), ozone (O₃), and volatile organic compounds (VOCs).

Water Pollution

Biological contamination: Presence of disease-causing microorganisms
Thermal pollution: Increased temperature of water bodies harming aquatic life
Sedimentary pollution: Increased accumulation of suspended particles impacting sunlight penetration and carrying chemical and biological pollutants
Chemical pollution: Release of harmful chemicals
Eutrophication: Selective stimulation of plant life in water at the expense of animals

Land Pollution

Municipal solid waste: Solid materials discarded by homes, businesses, and public institutions.
Sanitary landfills: Large waste disposal sites where garbage is compacted and covered.
Incineration: Combustion of waste reducing volume but generating hazardous waste (ash) that needs disposal.
Material composition of MSW: Breakdown of waste into various materials (plastics, metals, paper, food scraps, etc.)

Hazardous Waste

Chemical waste: Waste materials that may endanger public health or wildlife.
Persistent organic pollutants (POPs): Organic compounds resistant to degradation, and can accumulate in the environment, causing issues in bioaccumulation (accumulation in living tissues)
DDT (dichlorodiphenyltrichloroethane): A synthetic insecticide that resists degradation and poses threats to wildlife like birds, fish, and other animals. It is a chlorinated organic compound, and highly soluble in fats.

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Description

Test your knowledge about the significant developments in synthetic polymers, focusing on the contributions of Christian Schoenbein and the creation of celluloid. This quiz covers key applications, characteristics, and the processes that influence polymer resilience. Dive into the fascinating history of material science!