Polymers Flashcards
Benefits of off the shelf materials
Accessibility, specialized manufacturing, safety know for materials, FDA approved, time.
What roles does temperature play on a material?
Temperature can sterilize a material, but it can also denature the material.
Disadvantages of off the shelf materials
Materials are too generic, quality control hurdles, limited functionality, without new materials, it is hard to get fresh patents.
What can influence the structure and morphology of a material before and after creation?
Molecular structure and processing—> followed by usage
What are some characteristics that determine properties of a polymer?
Backbone and pendant groups, length of chain, Monomers or copolymer, chain shape (linear, branched etc.) and synthetic strategies.
Explain Chromatography
You can separate components of a mixture based on size of molecules. Small molecules get trapped, and larger molecules elute earlier.
Name 4 types of polymer arrangements
Linear Branched, Loose Network, and Tight Network.
Condensation Polymerization
2 monomers react to form a covalent bond, and water is released.
Addition Polymerization
Stages of Initiation, propagation, and termination.
Polyethylene Grades
LDPE, HDPE, UHMWPE, (Saran Wrap-Milk jug- hip replacement)
Polypropylene PP (classic example, and 3 isoforms)
Tupperware (isotactic, syndiotactic, atactic)
PVC
Different from polyethylene due to the Cl group. Good for tubing, but not under pressure. Sometimes brittle, so plasticizers are added.
PTFE
Polytetrafluoroethylene, very hydrophobic, used in vascular grafts, won’t react much with blood.
PMMA
Polymethyl methacrylate, hydrophobic, glassy, used for hard lenses and bone cement. Low permeability.
2-hydroxyethyl methacrylate p(HEMA)
Synthesized from PMMA, used in soft lenses and dental applications, WATER AND GAS PERMEABLE
What can you do to make something more water permeable?
Add a hydroxyl group!
Polyamides, Nylon (type of reaction, reason for strength, and use)
Condensation reaction, hydrogen bonding, and used for sutures.
How can you control the strength of Nylon (poly amides?)
Change the number of amide bonds available for hydrogen bonding.
Nylon “66” What does the 66 stand for?
The number of carbons on either side of the amide bond. In this case, 6 on each side.
In a polyurethane, which parts are strong, and which are elastic?
The rings are the hard part, and the other parts are elastic.
Degree of Polymerization
(DP) How many monomer units.
Polydispersity Index
Density
Glass Transition Temperature
temperature at which the polymer can become hard with high heat. atactic polymer Tg of 60, crystalline polymer Tg of 40.
