Molecular weight of polymers Flashcards
What are bulk/commodity polymers?
Make up majority of the goods we use in polymers
What commodity polymer is this? PE
Polyethylene
What commodity polymer is this? PVC
Poly(vinyl chloride)
What commodity polymer is this? PTFE
Polytetrafluoroethylene
What commodity polymer is this? PP
Polypropylene
What commodity polymer is this? PS
Polystyrene
What commodity polymer is this? PMMA
Poly (methyl methacrylate)
What commodity polymer is this? Bakelite
Phenol-formaldehyde
What commodity polymer is this? nylon 6,6
Poly(hexamethylene adipamide)
What commodity polymer is this? PET, a polyester
Poly( ethylene terephthalate)
What commodity polymer is this? PC
Polycarbonate
What are five unique features of polymeric materials?
- Synthesis
- Average molecular weight and molecular weight distribution
- Type of bonding
- Semicrystalline morphology
- Viscoelasticity
How much does packaging account for in thermoplastics?
1/3
How much does building and construction account for in thermosets use?
2/3
What is the molecular weight of polymers in g/mol?
> 20,000-3,000,000
Polymer chains within the same sample differ in what?
Molecular weight
What do processing and properties depend on dramatically?
Molecular weight
What is polymer molecular weight characterized by?
- Number average molecular weight
- Weight average molecular weight
- Dispersity
Molecular weight definition?
Mass of a mole of chains
What does molecular weight and distribution depend upon?
Type of polymerization reaction
What are the types of polymerization reactions?
- Step-growth polymerization
- Chain polymerization
What is the degree of polymerization?
average number of repeat units per chain
What are molecular weight characterization techniques?
- SEC
- LALS
-Vapor phase osmometry - Membrane osmometry
- Intrinsic viscosity
What do molecular weight and dispersity influence?
- Melting properties
- Mean squared end-to-end distance
- Viscosity
