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Home , Monomer, Organic Chemistry, Polymerization

Organic : Reactions

Today’s Objectives:

1) Define, illustrate, and give examples of , , and polymerization in living and non-living systems

STS: 2) Illustrate how science and technology are developed to meet societal needs and expand human capabilities

STS: 3) Illustrate how science and technology have both intended and unintended consequences

Section 10.5 (pg. 445-459) Polymerization

 Polymers are large made of chains of monomers, small molecules that link together.  Polymerization is the formation of polymers from these small units

 Polymers can occur naturally (, ) and can be synthesized (, Teflon, )

 They play an integral part in the function of systems and have revolutionized the way society functions Addition Polymerization

 Many (synthetic polymers) are made by this process

 The polymerization process is initiated with a free (a species with an unpaired electron). The free radical attacks and breaks the forming a new free radical that attacks another  Addition Polymerization always results in one product, the

 Requires unsaturated monomers and bond saturation occurs when the polymer is made

 Common polymers produced by addition polymerization: Things to know about addition polymers…

 The polymer names end in –ene (i.e. , polypropene). Does this mean they have double bonds?  No, the double bonds are saturated by adjacent monomers, as the polymer is made. The name refers to the starting monomer (i.e. polyethene is started by the monomer ethene)

 What properties make Teflon a good product for non-stick materials?  Teflon is made up of C-F bonds which are very strong (not C-H bonds). These very strong bonds make the Teflon highly unreactive (non-sticking), it has a high melting point and it has a slippery surface

Condensation Polymerization

 Monomers combine to form a polymer and a bi-product. Each time a bond forms between monomers, small molecules, such as water, , or HCl are “condensed” out.

 The polymerization of nylon: • For condensation polymerization to occur, monomers must be bifunctional, meaning they have at least two functional groups. • If they only had one , then only one bond would form. Condensation Polymerization

 Condensation polymerization also produces natural polymers, called proteins.

 Amino acids (monomers) polymerize to make (short chains of amino acids) or proteins (long chains of amino acids) Comparison of Addition and Condensation Polymerization

Addition Condensation

 Needs a double or  Needs bifunctional in the monomers (have two monomer functional groups)

 Produces only one  Produces two products: product, the polymer the polymer and the biproduct (water, ammonia or HCl)

 When a reacts with an in an esterification reaction, a water is eliminated and a single molecule is formed.

 This esterification reaction can be repeated so many are joined in a long chain… a polyester  This is created using a dicarboxylic acid (an acid with a carboxyl group at each end) and a (an alcohol with a hydroxyl group at each end)  The ester linkages are formed end to end between alternating acid and alcohol molecules Polyester: Dacron

 Another example of a polyester:

 Note the two carboxyl groups in the dicarboxylic acid and the two hydroxyl groups in the polyalcohol that start the chain reaction Natural Polymer Examples

, wood, silk, DNA Today’s homework

 Pg. 448 #2-4

 Pg. 452 #13

 Pg. 455 #16, 17  Due tomorrow

 What is coming up tomorrow?  Review for Unit Exam

Learning Tip Pg. 441

Unit Exam Chemistry 30 Organic Review