polymers

Polymers

long, typically carbon-based molecule or groups of molecules consisting of many repeating units called monomers

Macromolecule

any molecule containing a very large number of atoms

Polymer typical molecular weight

5000-2000000 g/mol

Polymer applications

structural, electronics, transportation, clothing

Drawing polymer structure

-ball and stick model

-linear chain representation

-abbreviated linear chain

Polymers of note

-polyethelyne (PE)
-poly(vinyl chloride) (PVC)

-polystyrene (PS)

-polydimethylsiloxane (PDMS)

Addition polymerization

monomers are added one at a time to form a polymer

1. Initiation: a catalyst or initiator reacts with a monomer to form an active center

2. Propagation: polymer chain reacts with additional monomers, grows in the process

3. Termination: active centers react, stopping the reaction

Ways to characterize polymer chain lengths

-number averaged molecular weight

-weight averaged molecular weight

-degree of polymerization (avg # of repeating units in a polymer chain)

Molecular weights importance

the size and shape of a polymer govern its properties, including melting temperature and mechanical properties

Calculating number averaged molecular weight

sum[(# fraction of molecules)(molecular weight)]

Calculating weight averaged molecular weight

sum[(weight fraction of molecules)(molecular weight)]

Calculating degree of polymerization

(# avg molecular weight)/(weight of the monomer)

Determining avg molecular weight using graphs

use middle value of each bar as value for that set