Synthetic materials

Materials Science
Synthetic Technology, Lesson 1
What are the properties of materials?
A material is the matter from which a substance is or can be made. Different materials have different properties.  You can use the properties of a material to find out how it can be used.
Material Properties:  Every kind of material can be identified by its physical and chemical properties.  Properties can also be used to describe materials.  For example, a material might be strong and flexible.  It might be soft and absorbent.  It might conduct heat or electricity.
The properties of a material can determine its behavior and its uses.  A material’s properties can also change.  They might change depending on how the material is treated or how it is stored.
What are the differences between natural and synthetic materials?
Some kinds of materials, such as wood and rock, are natural materials.  A natural material is any physical matter that is obtained or made from plants, animals, or the ground.  Natural materials come from the natural environment, and have been changed very little.
Plastics are an example of a synthetic material.  A synthetic material is a material that is obtained from a natural material which has undergone a chemical reaction in a laboratory or factory.  Both natural and synthetic materials are found in products you use every day.

Developing Synthetic Materials:  Materials scientists research and develop new materials.  A materials scientist looks for connections between the structure of a material and its properties.  That information is used to develop ways to change or improve materials.
Ideas for synthetic materials often come from natural materials.  For example, sea cucumbers are an organism that are soft and flexible to hide in crevices, but when danger is near, their skin turns tough like armor.  Materials scientists are trying to make a fabric that will copy this behavior by going from flexible to inflexible for brain implants in patients who are paralyzed.  Current electrodes are made out of metal, which can damage brain tissue in just a few months.  Researchers found that the sea cucumbers skin is made of ultra-fine cellulose fibers that bind together to form a shield when in defense mode. These fibers have been extracted from sea cucumbers and mixed with polymers and plastics to try to create a new material.   Any new synthetic material is a technology – the practical use of scientific knowledge.

Sources of Synthetic Materials:  All matter must come from somewhere.  Scientists use existing kinds of materials to make new synthetic materials.  The materials they use must come from natural resources.  These materials are obtained from plants, animals, or Earth.
How are Synthetic Materials Formed?   You’ve read that synthetic materials come from natural resources.  The ideas for new synthetic materials come from nature.  But how are synthetic materials formed?
New Materials – Throughout history, humans have changed natural materials to improve their properties.  The changes to natural materials result in new materials.   Natural materials undergo chemical reactions.  The atoms of the natural material rearrange and form synthetic material.
From Reactants to Products – Synthetic materials are the result of chemical reactions.  You might recall that in a chemical reaction, the bonds between atoms in the reactants are broken.  The atoms rearrange and make new bonds to form products.

A polymer is a molecule made up of many small organic molecules bonded together, forming a long chain.  A monomer is one of the small organic molecules that makes up the long chain of a polymer.  Polymer chains can be very long.

Characteristics of Synthetic Materials – There are different types of synthetic materials.  They are all made from natural resources that were changed in chemical reactions.  They are all made with specific properties to carry out a specific function. 
Examples of Synthetic Materials – Examples of synthetic materials include synthetic fibers, ceramics, polymers, artificial foods and medicines, and composites.
Synthetic fibers are flexible.  They can be used to make clothing and other objects.  Some examples of synthetic fibers are rayon, polyester, and nylon.  Ceramics are strong but brittle.  They are good insulators.  Some familiar examples of ceramics are cement, tiles, and bone china.
Rayon is made from purified cellulose, harvested primarily from wood pulp, which is chemically converted into a soluble compound. It is then dissolved and forced through a spinneret to produce filaments which are chemically solidified, resulting in fibers of nearly pure cellulose.[3] Unless the chemicals are handled carefully, workers can be seriously harmed by the carbon disulfide used to manufacture most rayon
Polyester fibers are sometimes spun together with natural fibers to produce a cloth with blended properties. Cotton-polyester blends (polycot) can be strong, wrinkle and tear-resistant, and reduce shrinking. Synthetic fibers using polyester have high water, wind and environmental resistance compared to plant-derived fibers. They are less fire resistant and can melt when ignited.[1]
The main difference between bone china and fine china is that bone china mixes cow bone ash into the ceramic material… They don’t do this to make the material stronger; they mix cow bone ash to give it a unique color tone. 

Polymers are strong and flexible.  They can be easily modified to hold different shapes and color.  Examples of polymers include polyester, nylon, and acrylic.  Many common objects are made of synthetic polymers.  You might be familiar with some of them.  Pipes made of polyvinyl chloride (PVC) are used in plumbing.  Some home siding, rainwear, and garden hoses are also made of polyvinyl chloride.  The polymer polytetrafluoroethylene (pah lee the truh flor oh ETH uh leen) is used for the nonstick coating on cookware.  Many types of synthetic ropes are made of polypropylene.

Some food and medicines are synthetic materials.  These are made for a specific function or to mimic, or copy, a natural material.  Some synthetic foods and medicines include vitamin C, red 40, and hydrogenated oils.  Composites are made to emphasize a specific property, like flexibility or strength.  Types of composites include concrete, plywood, and fiberglass.
Hydrogenation is a chemical process that converts liquid vegetable oil into solid fat. Partially hydrogenated oils, such as shortening and soft margarine, are semi-soft. Oils that are fully hydrogenated are firmer, and don't contain any of the dangerous artery-inflaming trans fat found in partiallyhydrogenated oils.  Both trans fats and saturated fats contribute to your risk of heart disease.
The Food and Drug Administration (FDA) has determined that partially hydrogenated vegetable oil is no longer "generally recognized as safe" and should be phased out of the production of food over the next several years. However, naturally-occurring trans fats will still be found in some foods.

Synthetic Materials and Societal Impacts, Lesson 2
What limits the production and use of synthetic materials?    Many of the products we use, such as cell phones, are made up of different synthetic materials.  Not every country has the same natural resources.  Humans depend on Earth’s land, ocean, atmosphere, and biosphere for natural resources.  Many of the resources are limited.  Some are not renewable, meaning they cannot be replaced over human lifetimes. 
Natural Resource Availability – Resources are distributed unevenly around Earth.  For example, some countries have a big supply of iron ore, which is used to make steel.  Other countries have very little iron ore.  Climate plays a role in what resources are available.  The climate in Russia is good for growing trees.  Timber is one of Russia’s resources.

Synthetic Material Production – The production of synthetic materials varies from region to region.  This due to differences in climate and the natural resources that are available.  Economic conditions also determine which synthetic materials are made and used.  Sometimes, effort is spent on synthetic products that provide for basic living needs.  When the economic conditions are better, more effort can be put into synthetic materials for purposes such as entertainment.
What are the impacts of synthetic materials on individuals and societies?      The need for new synthetic materials can come from society.  Technologies are developed based on the needs, wants, and values of the people in an area.  Other technologies are developed based on the needs or wants of individuals.  For example, phones developed so people could communicate over long distances.  Cell phones are used all around the world.  They have many impacts on individuals and society.
Individual and Societal Impacts:  Synthetic materials can have impacts on individuals and societies, depending on how the material is used.  For example, ethanol is a renewable fuel made from plant materials.  It has a variety of impacts on individuals and on society.  Gasoline mixed with ethanol is less expensive than regular petroleum-based gasoline.  Use of ethanol reduces the cost of fuel for individuals.
Ethanol has other impacts at the society level.  When it is used, there is less need for petroleum-based gasoline.  When ethanol burns, fewer pollutants are released.  It reduces the amount of smog and acid rain created by vehicles.
What are the impacts of synthetic materials on the environment?    The natural resources used to make synthetic materials come from the environment.  They are removed from Earth or harvested or farmed from land or water.  As demand for a synthetic material increases, the demand for the natural resources used to make the material also increases.
Sometimes, getting the resources needed to make a synthetic material causes large changes in that biosphere.  For example, draining a wetland can create a lot of land for growing corn, which can be used to make ethanol.  But, draining the wetland and planting a single crop damages the habitat of the organisms that lived in the wetland.  It could cause the extinction of some species.  The long-term functioning and health of any ecosystem is affected by human society.
The methods people use to extract, harvest, transport, and consume natural resources affects natural systems.   For example, palm oil is used to make many synthetic materials.  The oil is often found in products such as bread, ice cream, and other processed foods, as it is trans-fat free, as well as some cosmetics such as makeup and soap.  The biodiversity of an area decreases when rain forests are cleared to grow palm trees.  As the use of a synthetic material increases, so does the use of the natural materials used to make the synthetic material.  This increases the negative impacts to Earth.

The main issue with palm oil is its extremely harmful impact on the planet.  The trees, which were previously found only in Africa, are now grown in Asia, North America and South America - coinciding with the increasing demand for the versatile oil.  To keep up with the incredibly high demand for the cheaply produced oil, acres of rainforest are being cut down - leading to a loss of animal habitat for endangered species.  In the past 16 years, the quest for palm oil has led to the death of an estimated 100,000 orangutans, according to research.
Changes to the biodiversity of an area due to habitat destruction can affect other resources.  For example, if a rainforest is cleared to grow crops, the other resources provided by the rainforest are no longer available.  Changes to an area can affect how the biome cleans the water that humans drink.  The changes also affect how the biome recycles nutrients.  As organisms compete for limited resources, their growth and reproduction can be limited.
By-Products:  To make ethanol from plant materials, the plant materials have to undergo a chemical reaction.  Sometimes when a chemical reaction occurs, a secondary product is also created.  A by-product is a secondary product that results from a manufacturing process or chemical reaction.  The chemical reaction that produces ethanol  is shown in the figure below.  It shows that the reaction also makes carbon dioxide as a by-product.

A by-product can be useful, or it can be considered a waste.  If a by-product is considered waste, it must be disposed.  Disposal of waste by-products can impact society and the environment.
What happens when the synthetic material itself needs to be disposed?  For example, more than 125 million cell phones were thrown away in 2010.  Gold is one of the natural resources used to make cell phones.  That means 10,000 pounds of gold was thrown away with all of those phones.  Even though there are ways to recycle or reuse cell phones, many end up in landfills or incinerators.  Many other synthetic materials and products containing them are disposed of in the same ways.

Some synthetic materials have been designed to help reduce human impact on the environment.  For example, new fertilizers coated in synthetic polymers have been developed.  These fertilizers release nutrients to the soil over time.

Engineering advances have led to scientific discoveries.  These scientific discoveries have led to the development of whole industries and engineered systems, as shown in the pictures below.

Some people might wonder why synthetic materials haven’t been developed to reduce every negative impact humans have on the environment.  Remember that the development of synthetic materials is limited by current scientific research.  Materials cannot be created out of nothing.  That is why humans rely on natural resources to make synthetic materials.  Science is always advancing.  What might not be possible today might be possible tomorrow.