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Life Without Polymers
Transcript of Life Without Polymers
The first synthetic polymer produced was Bakelite in 1909 and was soon followed by the first semi- synthetic fiber, rayon, which was developed in 1911.
After World War II and through the 1950s rapid developments in synthetic polymers were made. Most commercial high-performance elastomers trace their origins to the 1960s and 1970s. History of Polymers Polymers are molecules that consist of a long, repeating chain of smaller units called monomers.
Monomers are molecules typically about 4-10 atoms in size, and are reactive in that they bond readily to other monomers in a process called polymerization
The word is derived from Greek, poly means many and meros means part. Introduction
Proteins, made up of amino acids, and many other molecules that make up life are polymers.
They are the largest and most diverse class of known molecules and even include plastics.
Imagining life without polymers is a challenge. Cells build our bodies, and cells are built of polymers. Plants are built of cellulose, which is a polymer. If polymers would suddenly disappear, life would disappear with it Thermoplastics such as polyethylene, which soften on heating.
Thermosets or resins such as epoxi which harden when two components are heated together.
Elastomers or rubbers
Natural polymers such as cellulose, lignin and protein, which provide the mechanical basis of most plant and animal life Classification of Polymers It as a polymer alloy which could replace metals in many applications.
Thermoplastics are made by adding together (polymerizing) sub-units (“monomers”) to form long chains.
may be hydrogen(polyethylene)orCH3(polypropylene) or -Cl (Polyvinylchloride). Thermoplastics Polymers which show “rubbery” behavior at their operating temperature are called “elastomeric”
Elastomers are linear polymers with occasional-cross links. These cross-link provide a memory so it returns to its original shape on unloading.
The prototype is “natural rubber”. Elastomeric Materials The two types of polymer configurations are cis and trans.
The cis configuration arises when substituent groups are on the same side of a carbon-carbon double bond.
Trans refers to the substituent's on opposite sides of the double bond. Configuration of Polymers Structure of polymers Properties In 1907 Leo Bakeland patented Bakelite, the first fully synthetic polymer.
This hard plastic was used as an electrical insulator and paved the way for the more than 60,000 different synthetic plastics on the market today.
Each year companies manufacture more than 30 million tons of plastics that are used in myriad of applications. Importance of polymers Commercial Importance
-Artificial heart valves
-hemodialysis. Medical Importance Polymers with controlled biomedical degradation characteristics can be used as an important part of tissue engineering and drug delivery therapies.
Many types of natural and synthetic biodegradable polymers have been investigated for medical and pharmaceutical applications. While use of natural polymers, such as cellulose and starches, is still common in biomedical research, synthetic biodegradable polymers are increasingly used in pharmaceutical and tissue-engineering products. Biodegradable Polymers We wear clothes containing polyester and nylon fibers, eat food packaged in polyethylene containers, drink water delivered through polyvinyl chloride pipes, walk on carpets made of polyolefin fibers, and sleep on mattresses made of polyurethane foam.
The variety of applications of synthetic polymers is mind-boggling. Conclusion http://www.allsealsinc.com/allseals/Orings/or01.htm
http://www.sigmaaldrich.com/materials-science/polymer-science/resomer.html References Human DNA is a polymer with over 20 billion constituent atoms. LINEAR BRANCHED NETWORK nylon, polyester, PVC, PAN etc. polythene, glycogen, starch Bakelite