The monomer structure of polystyrene is shown below:
(a) Would you expect polystyrene to be a stiff or a pliable polymer?
1)Stiff
2)Pliable
(b) What kind of synthesis is used in the production of polystyrene from styrene monomers?
1)Addition polymerization
2)Condensation polymerization
3)Anionic polymerization
(c) Calculate the degree of polymerization n of polystyrene with a molecular weight of 3.091×106 g/mol.
A. stiff
B. Addition polymerization
(c) 3.091×10^6 / 104.15 = 29678.34
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(a) To determine whether polystyrene is a stiff or a pliable polymer, we can analyze the monomer structure and consider its characteristics. Polystyrene is a linear polymer made up of repeating units of styrene monomers. Styrene itself is a relatively rigid molecule due to its aromatic structure and the presence of a phenyl group. When these monomers polymerize, they form long chains that are relatively rigid and tight.
Therefore, polystyrene is expected to be a stiff polymer rather than a pliable one.
(b) The synthesis used in the production of polystyrene from styrene monomers is addition polymerization. Addition polymerization involves the joining of monomers without the loss of any small molecules, typically through the breaking of multiple bonds. In the case of polystyrene, the double bond in the styrene monomers is broken, and each styrene unit adds to the growing polymer chain without the release of any byproduct.
Therefore, the correct answer is 1) Addition polymerization.
(c) To calculate the degree of polymerization (n) of polystyrene based on its molecular weight (Mw), we can use the following equation:
Mw = Mn * n
Where Mw is the molecular weight of the polymer, Mn is the molecular weight of the repeating unit (monomer), and n is the degree of polymerization.
Given the molecular weight of polystyrene as 3.091×10^6 g/mol, we need to determine the molecular weight of the repeating unit (styrene monomer) to proceed with the calculation.
The molecular weight of a styrene monomer is approximately 104.14 g/mol.
Now, we can substitute the values into the equation and solve for n:
3.091×10^6 g/mol = 104.14 g/mol * n
n = 3.091×10^6 g/mol / 104.14 g/mol
n ≈ 29,670
Therefore, the degree of polymerization (n) of polystyrene is approximately 29,670.