Chapter 11: Polymers

Introductory Activity What is a polymer? Observe some polymer products your teacher shows you.  They are all made of polymers, yet they behave very differently. How can we explain this?  Are you surprised that any of these products are “polymers”?

Polymers This chapter will introduce the chemistry needed to understand how Polymers are used to make products  Section 11.1: Hydrocarbons  Section 11.2: Organic Functional Groups  Section 11.3: Polymers

Polymers Monomers Are made of Organic compounds Which are Structure Properties vary with Bond type Which contains chains of Carbon atoms Can be Functional Group

Section 11.1—Hydrocarbons What type of molecules form the backbone of polymers?

Organic Molecules & Hydrocarbons Organic Molecule – Contains carbon atoms bonded to other carbon atoms Hydrocarbons – Molecule composed of carbon and hydrogen only All carbon atoms need 4 bonds to have a stable valence shell of 8 electrons. It can be any combination of single, double or triple that adds up to 4 total for each carbon. Hydrogen atoms are filled in around the carbon back-bone to give each carbon atom 4 bonds.

Properties of hydrocarbons Non-polar molecules Only intermolecular force is London Dispersion Forces  Most cannot dissolve in water—only the very small may be able to Larger hydrocarbons have larger London Dispersion Forces than smaller hydrocarbons  Larger hydrocarbons have higher melting and boiling points than smaller hydrocarbons

Alkanes Alkanes – Hydrocarbons containing only single bonds

Naming Alkanes The longest chain of carbons is counted and the number is used to determine the prefix (see table) “-ane” is used as the suffix TABLE 11-1—ORGANIC PREFIXES NUMBER OF CARBON ATOMS IN LONGEST CHAIN PREFIX 1Meth- 2Eth- 3Prop- 4But- 5Pent- 6Hex- 7Hept- 8Oct- 9Non- 10Dec-

Example #1 Example: Name the following molecule

Example #1 Example: Name the following molecule Find the longest chain of carbon atoms 4 A chain of 4 carbons = but- All single bonds = -ane butane

Let’s Practice #1 Draw a molecule of hexane

Let’s Practice #1 Draw a molecule of hexane Hex- = 6 carbons in a chain -ane = all single bonds Fill in with hydrogen atoms to give each carbon atom 4 bonds

Alkenes Alkenes – Hydrocarbons containing a double bond

Naming Alkenes Count the longest chain of carbon atoms and choose the appropriate prefix Count which carbon the double bond is on—count from the end CLOSEST to the double bond.  Put this number in front of the prefix Use the suffix “-ene”

Example #2 Example: Name the following molecule

Example #2 Example: Name the following molecule Find the longest chain of carbon atoms A chain of 4 carbons = but- 4

Example #2 Example: Name the following molecule Find the longest chain of carbon atoms A chain of 4 carbons = but- Count where double bond is from the side closest to it 2-butene In this case, when you count from either side, the double bond begins on the 2 nd carbon, so it doesn’t matter what side you count from 4 A double bond = -ene 2 nd carbon

Let’s Practice #2 Name the following molecule

Let’s Practice #2 Name the following molecule Find the longest chain of carbon atoms A chain of 7 carbons = hept- 7

Let’s Practice #2 Name the following molecule Count where double bond is from the side closest to it 3-heptene From right, it’s on the 4 th carbon. From left, it’s on the 3 rd carbon. Pick the lower number A double bond = -ene 4 th carbon 3 rd carbon Find the longest chain of carbon atoms A chain of 7 carbons = hept- 7

Alkynes Alkynes – Hydrocarbons containing a triple bond

Naming Alkynes Count the longest chain of carbon atoms and choose the appropriate prefix Count which carbon the triple bond is on— count from the end CLOSEST to the triple bond.  Put this number in front of the prefix Use the suffix “-yne”

Let’s Practice #3 Draw a molecule of 1-butyne

Let’s Practice #3 Draw a molecule of 1-butyne 1 = triple bond begins on the first carbon Fill in with hydrogen atoms so that each carbon has 4 bonds But- = 4 carbons -yne = triple bond

Isomers Isomers – Molecules with the same chemical formula, but a different molecular structure Often, alkenes and alkynes can be isomers of each other. Both of these have the formula C 3 H 4 but have different structures, as described by their different names. 1, 2—Propadiene1-Propyne

Saturation Saturated hydrocarbon – All single bonds—the molecule is “saturated” with as many hydrogen atoms as it can hold Saturated molecules can pack together tighter and form more intermolecular connections. Saturated molecules therefore have higher melting and boiling points Saturated Unsaturated

Hydrocarbon Side-branches Hydrocarbon side-branches – Some molecules have groups of hydrocarbons branching off the main chain of carbons.

Naming hydrocarbon side-branches Count the longest chain of carbon atoms (even if it’s not in a straight line) and choose the appropriate prefix Count which carbon the side-branch is on— count from the end CLOSEST to the side chain. Count the length of this side-chain and choose the appropriate prefix  Use “carbon #-organic prefix” at the very beginning of the molecule name  If there is more than one side-branch, separate them with commas Use an appropriate suffix.

Example #3 Example: Name the following molecule

Example #3 Example: Name the following molecule Find the longest chain of carbon atoms A chain of 7 carbons = hept- 7 7 carbons 6 carbons 4 carbons

Example #3 Example: Name the following molecule Count where side-chain is from the end closest to it 3-methyl heptane From the closest end, it’s on carbon #3 A double bond = -ene Find the longest chain of carbon atoms A chain of 7 carbons = hept- 7 Side-chain 7 carbons The side-chain has 1 carbon = meth-