Chapter 14 - Polymers Flashcards
What is a polymer?
A long chain of hydrocarbons bonded together by covalent bonds
What is the difference between saturated and unsaturated polymers?
Saturated only have single bonds
What is a monomer?
Smallest repeating unit of a polymer
What are the 3 steps of polymerization?
Initiation (a monomer with a free radical instead of double bond breaks another monomer’s double bond), propagation (chain reaction), and termination (monomer with free radical connects to and ends the chain)
What does the weight of the polymer molecule depend on?
Viscosity and osmotic pressure
What are the two ways of determining the molecular weight of a polymer
Either by number of chains within same size range, or weight fraction of molecules within same size range
How is the degree of polymerization defined?
The mean number average over the monomer’s molecular weight
What is the average weight of the monomer if there are two different repeating units
the sum of the chain fraction of the monomer times the molecular weight of the monomer
What does the amount of bonds between atoms effect the flexibility of a polymer
Single chain bonds can rotate in 3 dimensions, while double bonds are rotationally rigid
What are branched polymers?
The polymers branch off, and have lower density due to less packing efficiency
What are the factors that go towards polymer properties?
Molecular weight, shape, structure differences, and molecular chains
What are crosslinked polymers?
Adjacent polymer chains are joined together by covalent bonds
What are network polymers?
Heavily crosslinked polymers
What are thermoplastics?
Polymer materials that soften when heated, harden when cooled, and secondary bonding forces are diminished when temperature increases
Which structures do thermoplastics have?
Linear and branched due to the secondary bonding forces being weak at high temps
