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Chapter 2- Polymer Chemistry

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1 Chapter 2- Polymer Chemistry

2 2.1 Introducting Polymers
Monomer: the smallest repeating unit of a polymer (propene in polypropylene). Polymer: a long chain molecule made up of many small identical units (monomers). Polymerization: process of linking monomer units into a polymer. Can be accomplished by addition or condensation reactions. Homopolymer: a polymer made of only a single type of monomer Copolymere: are polymers made of two or more types fo monomers

3 Natural Polymers Nature produces a variety of polymers.
They are built by an organism. Examples are : Silk, natural rubber, starch, chitin, proteins,

4 Synthetic Polymers Usually produced from plant material or petrochemicals Examples include: Nylon, Kevlar, non-stick coating (fluoropolymers), polyester, tires

5 Synthetic Polymers involve 3 stages in the polymerization process
1 Initiation- removes a part of the monomer to make it want to bond with another monomer 2 Propagation- the process keeps going 3 Termination- a chemical is used that causes the monomers to stop joining together

6 2.2 Synthetic Addition Polymers
Addition polymerization: a reaction in which unsaturated monomers combine with each other to form a polymer. A reaction where monomers with double bonds are joined together through multiple addition reactions to form a polymer

7 Properties of a polymer are determined by the properties of its monomers, which may include functional groups such as alkyl groups, halides, aromatic groups and alcohols.

8 Examples of Addition Polymers
Teflon, polypropylene, polyester, polyethylene (pop bottles, grocery bags), polystyrene (packing material), Plexiglas, polyvinyl chloride (vinyl), natural rubber, etc

9 Example Polyvinyl Chloride
Example Polystyrene

10 Plastics A polymer that retains its shape after being heated under pressure and subsequently cooled. Plastics tend to be: Unreactive Flexible in Shape Vary in hardness

11 Polymer Cross-Linking
Cross-linking arises when functional groups on a chain can interact. The softness of a plastic is related to the amount of cross-linking. The greater the level of cross-linking, the more heat resistant a polymer becomes

12 Work Pg. 83 # 1-3 Pg. 87 # 1-3 Pg. 93 # 1-4

13 2.4 Synthetic Condensation Polymer
Condensation polymerization: a reaction in which two different monomers react at the functional group to form a polymer. Generally a reaction where two monomers are joined to form a unit called a dimer. A dimer generally consists of an ester or amide linkage. If a chemical is bi-functional (having two different functional groups) it can form a condensation polymer with itself.

14 Question what types of chemicals do we need to use to get the dimers?
Polyamide A dicarboxylic acid and diamines Polyester A diacarboxylic acid and dialcohols

15 Condensation Reaction
With two different molecules: With one type of molecule:

16 Polyester

17 The Formation of Dacron

18 Formation of Nylon 6,6

19 Work Pg. 98 # 1 Pg. 99 # 1-6


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